Add SQLite support, fix un-thread-safe DB caches, small performance f… (#172)

* Add SQLite support, fix un-thread-safe DB caches, small performance fixes

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

* add SQLite licenses to README

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

* appease the linter, and fix my dumbass-ery

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

* make requested changes

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

* add back comment

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

internal/cache/status.go

@@ -0,0 +1,106 @@
+package cache
+
+import (
+	"sync"
+
+	"github.com/ReneKroon/ttlcache"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+)
+
+// statusCache is a wrapper around ttlcache.Cache to provide URL and URI lookups for gtsmodel.Status
+type StatusCache struct {
+	cache *ttlcache.Cache   // map of IDs -> cached statuses
+	urls  map[string]string // map of status URLs -> IDs
+	uris  map[string]string // map of status URIs -> IDs
+	mutex sync.Mutex
+}
+
+// newStatusCache returns a new instantiated statusCache object
+func NewStatusCache() *StatusCache {
+	c := StatusCache{
+		cache: ttlcache.NewCache(),
+		urls:  make(map[string]string, 100),
+		uris:  make(map[string]string, 100),
+		mutex: sync.Mutex{},
+	}
+
+	// Set callback to purge lookup maps on expiration
+	c.cache.SetExpirationCallback(func(key string, value interface{}) {
+		status := value.(*gtsmodel.Status)
+
+		c.mutex.Lock()
+		delete(c.urls, status.URL)
+		delete(c.uris, status.URI)
+		c.mutex.Unlock()
+	})
+
+	return &c
+}
+
+// GetByID attempts to fetch a status from the cache by its ID
+func (c *StatusCache) GetByID(id string) (*gtsmodel.Status, bool) {
+	c.mutex.Lock()
+	status, ok := c.getByID(id)
+	c.mutex.Unlock()
+	return status, ok
+}
+
+// GetByURL attempts to fetch a status from the cache by its URL
+func (c *StatusCache) GetByURL(url string) (*gtsmodel.Status, bool) {
+	// Perform safe ID lookup
+	c.mutex.Lock()
+	id, ok := c.urls[url]
+
+	// Not found, unlock early
+	if !ok {
+		c.mutex.Unlock()
+		return nil, false
+	}
+
+	// Attempt status lookup
+	status, ok := c.getByID(id)
+	c.mutex.Unlock()
+	return status, ok
+}
+
+// GetByURI attempts to fetch a status from the cache by its URI
+func (c *StatusCache) GetByURI(uri string) (*gtsmodel.Status, bool) {
+	// Perform safe ID lookup
+	c.mutex.Lock()
+	id, ok := c.uris[uri]
+
+	// Not found, unlock early
+	if !ok {
+		c.mutex.Unlock()
+		return nil, false
+	}
+
+	// Attempt status lookup
+	status, ok := c.getByID(id)
+	c.mutex.Unlock()
+	return status, ok
+}
+
+// getByID performs an unsafe (no mutex locks) lookup of status by ID
+func (c *StatusCache) getByID(id string) (*gtsmodel.Status, bool) {
+	v, ok := c.cache.Get(id)
+	if !ok {
+		return nil, false
+	}
+	return v.(*gtsmodel.Status), true
+}
+
+// Put places a status in the cache
+func (c *StatusCache) Put(status *gtsmodel.Status) {
+	if status == nil || status.ID == "" ||
+		status.URL == "" ||
+		status.URI == "" {
+		panic("invalid status")
+	}
+
+	c.mutex.Lock()
+	c.cache.Set(status.ID, status)
+	c.urls[status.URL] = status.ID
+	c.uris[status.URI] = status.ID
+	c.mutex.Unlock()
+}

internal/cache/status_test.go

@@ -0,0 +1,41 @@
+package cache_test
+
+import (
+	"testing"
+
+	"github.com/superseriousbusiness/gotosocial/internal/cache"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+)
+
+func TestStatusCache(t *testing.T) {
+	cache := cache.NewStatusCache()
+
+	// Attempt to place a status
+	status := gtsmodel.Status{
+		ID:  "id",
+		URI: "uri",
+		URL: "url",
+	}
+	cache.Put(&status)
+
+	var ok bool
+	var check *gtsmodel.Status
+
+	// Check we can retrieve
+	check, ok = cache.GetByID(status.ID)
+	if !ok || !statusIs(&status, check) {
+		t.Fatal("Could not find expected status")
+	}
+	check, ok = cache.GetByURI(status.URI)
+	if !ok || !statusIs(&status, check) {
+		t.Fatal("Could not find expected status")
+	}
+	check, ok = cache.GetByURL(status.URL)
+	if !ok || !statusIs(&status, check) {
+		t.Fatal("Could not find expected status")
+	}
+}
+
+func statusIs(status1, status2 *gtsmodel.Status) bool {
+	return status1.ID == status2.ID && status1.URI == status2.URI && status1.URL == status2.URL
+}

internal/db/bundb/account.go

@@ -25,7 +25,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/sirupsen/logrus"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
@@ -34,8 +33,7 @@ import (
 
 type accountDB struct {
 	config *config.Config
-	conn   *bun.DB
-	log    *logrus.Logger
+	conn   *DBConn
 }
 
 func (a *accountDB) newAccountQ(account *gtsmodel.Account) *bun.SelectQuery {
@@ -52,9 +50,11 @@ func (a *accountDB) GetAccountByID(ctx context.Context, id string) (*gtsmodel.Ac
 	q := a.newAccountQ(account).
 		Where("account.id = ?", id)
 
-	err := processErrorResponse(q.Scan(ctx))
-
-	return account, err
+	err := q.Scan(ctx)
+	if err != nil {
+		return nil, a.conn.ProcessError(err)
+	}
+	return account, nil
 }
 
 func (a *accountDB) GetAccountByURI(ctx context.Context, uri string) (*gtsmodel.Account, db.Error) {
@@ -63,9 +63,11 @@ func (a *accountDB) GetAccountByURI(ctx context.Context, uri string) (*gtsmodel.
 	q := a.newAccountQ(account).
 		Where("account.uri = ?", uri)
 
-	err := processErrorResponse(q.Scan(ctx))
-
-	return account, err
+	err := q.Scan(ctx)
+	if err != nil {
+		return nil, a.conn.ProcessError(err)
+	}
+	return account, nil
 }
 
 func (a *accountDB) GetAccountByURL(ctx context.Context, uri string) (*gtsmodel.Account, db.Error) {
@@ -74,9 +76,11 @@ func (a *accountDB) GetAccountByURL(ctx context.Context, uri string) (*gtsmodel.
 	q := a.newAccountQ(account).
 		Where("account.url = ?", uri)
 
-	err := processErrorResponse(q.Scan(ctx))
-
-	return account, err
+	err := q.Scan(ctx)
+	if err != nil {
+		return nil, a.conn.ProcessError(err)
+	}
+	return account, nil
 }
 
 func (a *accountDB) UpdateAccount(ctx context.Context, account *gtsmodel.Account) (*gtsmodel.Account, db.Error) {
@@ -92,10 +96,10 @@ func (a *accountDB) UpdateAccount(ctx context.Context, account *gtsmodel.Account
 		WherePK()
 
 	_, err := q.Exec(ctx)
-
-	err = processErrorResponse(err)
-
-	return account, err
+	if err != nil {
+		return nil, a.conn.ProcessError(err)
+	}
+	return account, nil
 }
 
 func (a *accountDB) GetInstanceAccount(ctx context.Context, domain string) (*gtsmodel.Account, db.Error) {
@@ -113,9 +117,11 @@ func (a *accountDB) GetInstanceAccount(ctx context.Context, domain string) (*gts
 			WhereGroup(" AND ", whereEmptyOrNull("domain"))
 	}
 
-	err := processErrorResponse(q.Scan(ctx))
-
-	return account, err
+	err := q.Scan(ctx)
+	if err != nil {
+		return nil, a.conn.ProcessError(err)
+	}
+	return account, nil
 }
 
 func (a *accountDB) GetAccountLastPosted(ctx context.Context, accountID string) (time.Time, db.Error) {
@@ -129,9 +135,11 @@ func (a *accountDB) GetAccountLastPosted(ctx context.Context, accountID string)
 		Where("account_id = ?", accountID).
 		Column("created_at")
 
-	err := processErrorResponse(q.Scan(ctx))
-
-	return status.CreatedAt, err
+	err := q.Scan(ctx)
+	if err != nil {
+		return time.Time{}, a.conn.ProcessError(err)
+	}
+	return status.CreatedAt, nil
 }
 
 func (a *accountDB) SetAccountHeaderOrAvatar(ctx context.Context, mediaAttachment *gtsmodel.MediaAttachment, accountID string) db.Error {
@@ -153,17 +161,17 @@ func (a *accountDB) SetAccountHeaderOrAvatar(ctx context.Context, mediaAttachmen
 		NewInsert().
 		Model(mediaAttachment).
 		Exec(ctx); err != nil {
-		return err
+		return a.conn.ProcessError(err)
 	}
-
 	if _, err := a.conn.
 		NewUpdate().
 		Model(&gtsmodel.Account{}).
 		Set(fmt.Sprintf("%s_media_attachment_id = ?", headerOrAVI), mediaAttachment.ID).
 		Where("id = ?", accountID).
 		Exec(ctx); err != nil {
-		return err
+		return a.conn.ProcessError(err)
 	}
+
 	return nil
 }
 
@@ -174,9 +182,11 @@ func (a *accountDB) GetLocalAccountByUsername(ctx context.Context, username stri
 		Where("username = ?", username).
 		WhereGroup(" AND ", whereEmptyOrNull("domain"))
 
-	err := processErrorResponse(q.Scan(ctx))
-
-	return account, err
+	err := q.Scan(ctx)
+	if err != nil {
+		return nil, a.conn.ProcessError(err)
+	}
+	return account, nil
 }
 
 func (a *accountDB) GetAccountFaves(ctx context.Context, accountID string) ([]*gtsmodel.StatusFave, db.Error) {
@@ -187,8 +197,9 @@ func (a *accountDB) GetAccountFaves(ctx context.Context, accountID string) ([]*g
 		Model(faves).
 		Where("account_id = ?", accountID).
 		Scan(ctx); err != nil {
-		return nil, err
+		return nil, a.conn.ProcessError(err)
 	}
+
 	return *faves, nil
 }
 
@@ -201,7 +212,6 @@ func (a *accountDB) CountAccountStatuses(ctx context.Context, accountID string)
 }
 
 func (a *accountDB) GetAccountStatuses(ctx context.Context, accountID string, limit int, excludeReplies bool, maxID string, pinnedOnly bool, mediaOnly bool) ([]*gtsmodel.Status, db.Error) {
-	a.log.Debugf("getting statuses for account %s", accountID)
 	statuses := []*gtsmodel.Status{}
 
 	q := a.conn.
@@ -238,14 +248,13 @@ func (a *accountDB) GetAccountStatuses(ctx context.Context, accountID string, li
 	}
 
 	if err := q.Scan(ctx); err != nil {
-		return nil, err
+		return nil, a.conn.ProcessError(err)
 	}
 
 	if len(statuses) == 0 {
 		return nil, db.ErrNoEntries
 	}
 
-	a.log.Debugf("returning statuses for account %s", accountID)
 	return statuses, nil
 }
 
@@ -273,7 +282,7 @@ func (a *accountDB) GetAccountBlocks(ctx context.Context, accountID string, maxI
 
 	err := fq.Scan(ctx)
 	if err != nil {
-		return nil, "", "", err
+		return nil, "", "", a.conn.ProcessError(err)
 	}
 
 	if len(blocks) == 0 {

internal/db/bundb/admin.go

@@ -29,20 +29,17 @@ import (
 	"strings"
 	"time"
 
-	"github.com/sirupsen/logrus"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/id"
 	"github.com/superseriousbusiness/gotosocial/internal/util"
-	"github.com/uptrace/bun"
 	"golang.org/x/crypto/bcrypt"
 )
 
 type adminDB struct {
 	config *config.Config
-	conn   *bun.DB
-	log    *logrus.Logger
+	conn   *DBConn
 }
 
 func (a *adminDB) IsUsernameAvailable(ctx context.Context, username string) (bool, db.Error) {
@@ -52,7 +49,7 @@ func (a *adminDB) IsUsernameAvailable(ctx context.Context, username string) (boo
 		Where("username = ?", username).
 		Where("domain = ?", nil)
 
-	return notExists(ctx, q)
+	return a.conn.NotExists(ctx, q)
 }
 
 func (a *adminDB) IsEmailAvailable(ctx context.Context, email string) (bool, db.Error) {
@@ -72,7 +69,7 @@ func (a *adminDB) IsEmailAvailable(ctx context.Context, email string) (bool, db.
 		// fail because we found something
 		return false, fmt.Errorf("email domain %s is blocked", domain)
 	} else if err != sql.ErrNoRows {
-		return false, processErrorResponse(err)
+		return false, a.conn.ProcessError(err)
 	}
 
 	// check if this email is associated with a user already
@@ -82,13 +79,13 @@ func (a *adminDB) IsEmailAvailable(ctx context.Context, email string) (bool, db.
 		Where("email = ?", email).
 		WhereOr("unconfirmed_email = ?", email)
 
-	return notExists(ctx, q)
+	return a.conn.NotExists(ctx, q)
 }
 
 func (a *adminDB) NewSignup(ctx context.Context, username string, reason string, requireApproval bool, email string, password string, signUpIP net.IP, locale string, appID string, emailVerified bool, admin bool) (*gtsmodel.User, db.Error) {
 	key, err := rsa.GenerateKey(rand.Reader, 2048)
 	if err != nil {
-		a.log.Errorf("error creating new rsa key: %s", err)
+		a.conn.log.Errorf("error creating new rsa key: %s", err)
 		return nil, err
 	}
 
@@ -128,7 +125,7 @@ func (a *adminDB) NewSignup(ctx context.Context, username string, reason string,
 			NewInsert().
 			Model(acct).
 			Exec(ctx); err != nil {
-			return nil, err
+			return nil, a.conn.ProcessError(err)
 		}
 	}
 
@@ -167,7 +164,7 @@ func (a *adminDB) NewSignup(ctx context.Context, username string, reason string,
 		NewInsert().
 		Model(u).
 		Exec(ctx); err != nil {
-		return nil, err
+		return nil, a.conn.ProcessError(err)
 	}
 
 	return u, nil
@@ -184,15 +181,15 @@ func (a *adminDB) CreateInstanceAccount(ctx context.Context) db.Error {
 		WhereGroup(" AND ", whereEmptyOrNull("domain"))
 	count, err := existsQ.Count(ctx)
 	if err != nil && count == 1 {
-		a.log.Infof("instance account %s already exists", username)
+		a.conn.log.Infof("instance account %s already exists", username)
 		return nil
 	} else if err != sql.ErrNoRows {
-		return processErrorResponse(err)
+		return a.conn.ProcessError(err)
 	}
 
 	key, err := rsa.GenerateKey(rand.Reader, 2048)
 	if err != nil {
-		a.log.Errorf("error creating new rsa key: %s", err)
+		a.conn.log.Errorf("error creating new rsa key: %s", err)
 		return err
 	}
 
@@ -224,10 +221,10 @@ func (a *adminDB) CreateInstanceAccount(ctx context.Context) db.Error {
 		Model(acct)
 
 	if _, err := insertQ.Exec(ctx); err != nil {
-		return err
+		return a.conn.ProcessError(err)
 	}
 
-	a.log.Infof("instance account %s CREATED with id %s", username, acct.ID)
+	a.conn.log.Infof("instance account %s CREATED with id %s", username, acct.ID)
 	return nil
 }
 
@@ -240,12 +237,12 @@ func (a *adminDB) CreateInstanceInstance(ctx context.Context) db.Error {
 		Model(&gtsmodel.Instance{}).
 		Where("domain = ?", domain)
 
-	exists, err := exists(ctx, q)
+	exists, err := a.conn.Exists(ctx, q)
 	if err != nil {
 		return err
 	}
 	if exists {
-		a.log.Infof("instance entry already exists")
+		a.conn.log.Infof("instance entry already exists")
 		return nil
 	}
 
@@ -266,10 +263,10 @@ func (a *adminDB) CreateInstanceInstance(ctx context.Context) db.Error {
 		Model(i)
 
 	_, err = insertQ.Exec(ctx)
-	err = processErrorResponse(err)
-
-	if err == nil {
-		a.log.Infof("created instance instance %s with id %s", domain, i.ID)
+	if err != nil {
+		return a.conn.ProcessError(err)
 	}
-	return err
+
+	a.conn.log.Infof("created instance instance %s with id %s", domain, i.ID)
+	return nil
 }

internal/db/bundb/basic.go

@@ -21,9 +21,7 @@ package bundb
 import (
 	"context"
 	"errors"
-	"strings"
 
-	"github.com/sirupsen/logrus"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/uptrace/bun"
@@ -31,16 +29,12 @@ import (
 
 type basicDB struct {
 	config *config.Config
-	conn   *bun.DB
-	log    *logrus.Logger
+	conn   *DBConn
 }
 
 func (b *basicDB) Put(ctx context.Context, i interface{}) db.Error {
 	_, err := b.conn.NewInsert().Model(i).Exec(ctx)
-	if err != nil && strings.Contains(err.Error(), "duplicate key value violates unique constraint") {
-		return db.ErrAlreadyExists
-	}
-	return err
+	return b.conn.ProcessError(err)
 }
 
 func (b *basicDB) GetByID(ctx context.Context, id string, i interface{}) db.Error {
@@ -49,7 +43,8 @@ func (b *basicDB) GetByID(ctx context.Context, id string, i interface{}) db.Erro
 		Model(i).
 		Where("id = ?", id)
 
-	return processErrorResponse(q.Scan(ctx))
+	err := q.Scan(ctx)
+	return b.conn.ProcessError(err)
 }
 
 func (b *basicDB) GetWhere(ctx context.Context, where []db.Where, i interface{}) db.Error {
@@ -59,7 +54,6 @@ func (b *basicDB) GetWhere(ctx context.Context, where []db.Where, i interface{})
 
 	q := b.conn.NewSelect().Model(i)
 	for _, w := range where {
-
 		if w.Value == nil {
 			q = q.Where("? IS NULL", bun.Ident(w.Key))
 		} else {
@@ -71,7 +65,8 @@ func (b *basicDB) GetWhere(ctx context.Context, where []db.Where, i interface{})
 		}
 	}
 
-	return processErrorResponse(q.Scan(ctx))
+	err := q.Scan(ctx)
+	return b.conn.ProcessError(err)
 }
 
 func (b *basicDB) GetAll(ctx context.Context, i interface{}) db.Error {
@@ -79,7 +74,8 @@ func (b *basicDB) GetAll(ctx context.Context, i interface{}) db.Error {
 		NewSelect().
 		Model(i)
 
-	return processErrorResponse(q.Scan(ctx))
+	err := q.Scan(ctx)
+	return b.conn.ProcessError(err)
 }
 
 func (b *basicDB) DeleteByID(ctx context.Context, id string, i interface{}) db.Error {
@@ -89,8 +85,7 @@ func (b *basicDB) DeleteByID(ctx context.Context, id string, i interface{}) db.E
 		Where("id = ?", id)
 
 	_, err := q.Exec(ctx)
-
-	return processErrorResponse(err)
+	return b.conn.ProcessError(err)
 }
 
 func (b *basicDB) DeleteWhere(ctx context.Context, where []db.Where, i interface{}) db.Error {
@@ -107,8 +102,7 @@ func (b *basicDB) DeleteWhere(ctx context.Context, where []db.Where, i interface
 	}
 
 	_, err := q.Exec(ctx)
-
-	return processErrorResponse(err)
+	return b.conn.ProcessError(err)
 }
 
 func (b *basicDB) UpdateByID(ctx context.Context, id string, i interface{}) db.Error {
@@ -118,8 +112,7 @@ func (b *basicDB) UpdateByID(ctx context.Context, id string, i interface{}) db.E
 		WherePK()
 
 	_, err := q.Exec(ctx)
-
-	return processErrorResponse(err)
+	return b.conn.ProcessError(err)
 }
 
 func (b *basicDB) UpdateOneByID(ctx context.Context, id string, key string, value interface{}, i interface{}) db.Error {
@@ -129,8 +122,7 @@ func (b *basicDB) UpdateOneByID(ctx context.Context, id string, key string, valu
 		WherePK()
 
 	_, err := q.Exec(ctx)
-
-	return processErrorResponse(err)
+	return b.conn.ProcessError(err)
 }
 
 func (b *basicDB) UpdateWhere(ctx context.Context, where []db.Where, key string, value interface{}, i interface{}) db.Error {
@@ -151,8 +143,7 @@ func (b *basicDB) UpdateWhere(ctx context.Context, where []db.Where, key string,
 	q = q.Set("? = ?", bun.Safe(key), value)
 
 	_, err := q.Exec(ctx)
-
-	return processErrorResponse(err)
+	return b.conn.ProcessError(err)
 }
 
 func (b *basicDB) CreateTable(ctx context.Context, i interface{}) db.Error {
@@ -162,7 +153,7 @@ func (b *basicDB) CreateTable(ctx context.Context, i interface{}) db.Error {
 
 func (b *basicDB) DropTable(ctx context.Context, i interface{}) db.Error {
 	_, err := b.conn.NewDropTable().Model(i).IfExists().Exec(ctx)
-	return processErrorResponse(err)
+	return b.conn.ProcessError(err)
 }
 
 func (b *basicDB) IsHealthy(ctx context.Context) db.Error {
@@ -170,10 +161,6 @@ func (b *basicDB) IsHealthy(ctx context.Context) db.Error {
 }
 
 func (b *basicDB) Stop(ctx context.Context) db.Error {
-	b.log.Info("closing db connection")
-	if err := b.conn.Close(); err != nil {
-		// only cancel if there's a problem closing the db
-		return err
-	}
-	return nil
+	b.conn.log.Info("closing db connection")
+	return b.conn.Close()
 }

internal/db/bundb/bundb.go

@@ -30,15 +30,19 @@ import (
 	"strings"
 	"time"
 
+	"github.com/ReneKroon/ttlcache"
 	"github.com/jackc/pgx/v4"
 	"github.com/jackc/pgx/v4/stdlib"
 	"github.com/sirupsen/logrus"
+	"github.com/superseriousbusiness/gotosocial/internal/cache"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/id"
 	"github.com/uptrace/bun"
 	"github.com/uptrace/bun/dialect/pgdialect"
+	"github.com/uptrace/bun/dialect/sqlitedialect"
+	_ "modernc.org/sqlite"
 )
 
 const (
@@ -66,15 +70,14 @@ type bunDBService struct {
 	db.Status
 	db.Timeline
 	config *config.Config
-	conn   *bun.DB
-	log    *logrus.Logger
+	conn   *DBConn
 }
 
 // NewBunDBService returns a bunDB derived from the provided config, which implements the go-fed DB interface.
 // Under the hood, it uses https://github.com/uptrace/bun to create and maintain a database connection.
 func NewBunDBService(ctx context.Context, c *config.Config, log *logrus.Logger) (db.DB, error) {
 	var sqldb *sql.DB
-	var conn *bun.DB
+	var conn *DBConn
 
 	// depending on the database type we're trying to create, we need to use a different driver...
 	switch strings.ToLower(c.DBConfig.Type) {
@@ -85,10 +88,24 @@ func NewBunDBService(ctx context.Context, c *config.Config, log *logrus.Logger)
 			return nil, fmt.Errorf("could not create bundb postgres options: %s", err)
 		}
 		sqldb = stdlib.OpenDB(*opts)
-		conn = bun.NewDB(sqldb, pgdialect.New())
+		conn = WrapDBConn(bun.NewDB(sqldb, pgdialect.New()), log)
 	case dbTypeSqlite:
 		// SQLITE
-		// TODO: https://bun.uptrace.dev/guide/drivers.html#sqlite
+		var err error
+		sqldb, err = sql.Open("sqlite", c.DBConfig.Address)
+		if err != nil {
+			return nil, fmt.Errorf("could not open sqlite db: %s", err)
+		}
+		conn = WrapDBConn(bun.NewDB(sqldb, sqlitedialect.New()), log)
+
+		if strings.HasPrefix(strings.TrimPrefix(c.DBConfig.Address, "file:"), ":memory:") {
+			log.Warn("sqlite in-memory database should only be used for debugging")
+
+			// don't close connections on disconnect -- otherwise
+			// the SQLite database will be deleted when there
+			// are no active connections
+			sqldb.SetConnMaxLifetime(0)
+		}
 	default:
 		return nil, fmt.Errorf("database type %s not supported for bundb", strings.ToLower(c.DBConfig.Type))
 	}
@@ -108,66 +125,56 @@ func NewBunDBService(ctx context.Context, c *config.Config, log *logrus.Logger)
 		Account: &accountDB{
 			config: c,
 			conn:   conn,
-			log:    log,
 		},
 		Admin: &adminDB{
 			config: c,
 			conn:   conn,
-			log:    log,
 		},
 		Basic: &basicDB{
 			config: c,
 			conn:   conn,
-			log:    log,
 		},
 		Domain: &domainDB{
 			config: c,
 			conn:   conn,
-			log:    log,
 		},
 		Instance: &instanceDB{
 			config: c,
 			conn:   conn,
-			log:    log,
 		},
 		Media: &mediaDB{
 			config: c,
 			conn:   conn,
-			log:    log,
 		},
 		Mention: &mentionDB{
 			config: c,
 			conn:   conn,
-			log:    log,
+			cache:  ttlcache.NewCache(),
 		},
 		Notification: &notificationDB{
 			config: c,
 			conn:   conn,
-			log:    log,
+			cache:  ttlcache.NewCache(),
 		},
 		Relationship: &relationshipDB{
 			config: c,
 			conn:   conn,
-			log:    log,
 		},
 		Session: &sessionDB{
 			config: c,
 			conn:   conn,
-			log:    log,
 		},
 		Status: &statusDB{
 			config: c,
 			conn:   conn,
-			log:    log,
+			cache:  cache.NewStatusCache(),
 		},
 		Timeline: &timelineDB{
 			config: c,
 			conn:   conn,
-			log:    log,
 		},
 		config: c,
 		conn:   conn,
-		log:    log,
 	}
 
 	// we can confidently return this useable service now
@@ -332,7 +339,7 @@ func (ps *bunDBService) MentionStringsToMentions(ctx context.Context, targetAcco
 		if err != nil {
 			if err == sql.ErrNoRows {
 				// no result found for this username/domain so just don't include it as a mencho and carry on about our business
-				ps.log.Debugf("no account found with username '%s' and domain '%s', skipping it", username, domain)
+				ps.conn.log.Debugf("no account found with username '%s' and domain '%s', skipping it", username, domain)
 				continue
 			}
 			// a serious error has happened so bail
@@ -398,7 +405,7 @@ func (ps *bunDBService) EmojiStringsToEmojis(ctx context.Context, emojis []strin
 		if err != nil {
 			if err == sql.ErrNoRows {
 				// no result found for this username/domain so just don't include it as an emoji and carry on about our business
-				ps.log.Debugf("no emoji found with shortcode %s, skipping it", e)
+				ps.conn.log.Debugf("no emoji found with shortcode %s, skipping it", e)
 				continue
 			}
 			// a serious error has happened so bail

internal/db/bundb/conn.go

@@ -0,0 +1,72 @@
+package bundb
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/sirupsen/logrus"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/uptrace/bun"
+	"github.com/uptrace/bun/dialect"
+)
+
+// dbConn wrapps a bun.DB conn to provide SQL-type specific additional functionality
+type DBConn struct {
+	errProc func(error) db.Error // errProc is the SQL-type specific error processor
+	log     *logrus.Logger       // log is the logger passed with this DBConn
+	*bun.DB                      // DB is the underlying bun.DB connection
+}
+
+// WrapDBConn @TODO
+func WrapDBConn(dbConn *bun.DB, log *logrus.Logger) *DBConn {
+	var errProc func(error) db.Error
+	switch dbConn.Dialect().Name() {
+	case dialect.PG:
+		errProc = processPostgresError
+	case dialect.SQLite:
+		errProc = processSQLiteError
+	default:
+		panic("unknown dialect name: " + dbConn.Dialect().Name().String())
+	}
+	return &DBConn{
+		errProc: errProc,
+		log:     log,
+		DB:      dbConn,
+	}
+}
+
+// ProcessError processes an error to replace any known values with our own db.Error types,
+// making it easier to catch specific situations (e.g. no rows, already exists, etc)
+func (conn *DBConn) ProcessError(err error) db.Error {
+	switch {
+	case err == nil:
+		return nil
+	case err == sql.ErrNoRows:
+		return db.ErrNoEntries
+	default:
+		return conn.errProc(err)
+	}
+}
+
+// Exists checks the results of a SelectQuery for the existence of the data in question, masking ErrNoEntries errors
+func (conn *DBConn) Exists(ctx context.Context, query *bun.SelectQuery) (bool, db.Error) {
+	// Get the select query result
+	count, err := query.Count(ctx)
+
+	// Process error as our own and check if it exists
+	switch err := conn.ProcessError(err); err {
+	case nil:
+		return (count != 0), nil
+	case db.ErrNoEntries:
+		return false, nil
+	default:
+		return false, err
+	}
+}
+
+// NotExists is the functional opposite of conn.Exists()
+func (conn *DBConn) NotExists(ctx context.Context, query *bun.SelectQuery) (bool, db.Error) {
+	// Simply inverse of conn.exists()
+	exists, err := conn.Exists(ctx, query)
+	return !exists, err
+}

internal/db/bundb/domain.go

@@ -22,18 +22,15 @@ import (
 	"context"
 	"net/url"
 
-	"github.com/sirupsen/logrus"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/util"
-	"github.com/uptrace/bun"
 )
 
 type domainDB struct {
 	config *config.Config
-	conn   *bun.DB
-	log    *logrus.Logger
+	conn   *DBConn
 }
 
 func (d *domainDB) IsDomainBlocked(ctx context.Context, domain string) (bool, db.Error) {
@@ -47,7 +44,7 @@ func (d *domainDB) IsDomainBlocked(ctx context.Context, domain string) (bool, db
 		Where("LOWER(domain) = LOWER(?)", domain).
 		Limit(1)
 
-	return exists(ctx, q)
+	return d.conn.Exists(ctx, q)
 }
 
 func (d *domainDB) AreDomainsBlocked(ctx context.Context, domains []string) (bool, db.Error) {

internal/db/bundb/errors.go

@@ -0,0 +1,43 @@
+package bundb
+
+import (
+	"github.com/jackc/pgconn"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"modernc.org/sqlite"
+	sqlite3 "modernc.org/sqlite/lib"
+)
+
+// processPostgresError processes an error, replacing any postgres specific errors with our own error type
+func processPostgresError(err error) db.Error {
+	// Attempt to cast as postgres
+	pgErr, ok := err.(*pgconn.PgError)
+	if !ok {
+		return err
+	}
+
+	// Handle supplied error code:
+	// (https://www.postgresql.org/docs/10/errcodes-appendix.html)
+	switch pgErr.Code {
+	case "23505" /* unique_violation */ :
+		return db.ErrAlreadyExists
+	default:
+		return err
+	}
+}
+
+// processSQLiteError processes an error, replacing any sqlite specific errors with our own error type
+func processSQLiteError(err error) db.Error {
+	// Attempt to cast as sqlite
+	sqliteErr, ok := err.(*sqlite.Error)
+	if !ok {
+		return err
+	}
+
+	// Handle supplied error code:
+	switch sqliteErr.Code() {
+	case sqlite3.SQLITE_CONSTRAINT_UNIQUE:
+		return db.ErrAlreadyExists
+	default:
+		return err
+	}
+}

internal/db/bundb/instance.go

@@ -21,7 +21,6 @@ package bundb
 import (
 	"context"
 
-	"github.com/sirupsen/logrus"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
@@ -30,8 +29,7 @@ import (
 
 type instanceDB struct {
 	config *config.Config
-	conn   *bun.DB
-	log    *logrus.Logger
+	conn   *DBConn
 }
 
 func (i *instanceDB) CountInstanceUsers(ctx context.Context, domain string) (int, db.Error) {
@@ -49,8 +47,10 @@ func (i *instanceDB) CountInstanceUsers(ctx context.Context, domain string) (int
 	}
 
 	count, err := q.Count(ctx)
-
-	return count, processErrorResponse(err)
+	if err != nil {
+		return 0, i.conn.ProcessError(err)
+	}
+	return count, nil
 }
 
 func (i *instanceDB) CountInstanceStatuses(ctx context.Context, domain string) (int, db.Error) {
@@ -68,8 +68,10 @@ func (i *instanceDB) CountInstanceStatuses(ctx context.Context, domain string) (
 	}
 
 	count, err := q.Count(ctx)
-
-	return count, processErrorResponse(err)
+	if err != nil {
+		return 0, i.conn.ProcessError(err)
+	}
+	return count, nil
 }
 
 func (i *instanceDB) CountInstanceDomains(ctx context.Context, domain string) (int, db.Error) {
@@ -89,12 +91,14 @@ func (i *instanceDB) CountInstanceDomains(ctx context.Context, domain string) (i
 	}
 
 	count, err := q.Count(ctx)
-
-	return count, processErrorResponse(err)
+	if err != nil {
+		return 0, i.conn.ProcessError(err)
+	}
+	return count, nil
 }
 
 func (i *instanceDB) GetInstanceAccounts(ctx context.Context, domain string, maxID string, limit int) ([]*gtsmodel.Account, db.Error) {
-	i.log.Debug("GetAccountsForInstance")
+	i.conn.log.Debug("GetAccountsForInstance")
 
 	accounts := []*gtsmodel.Account{}
 
@@ -111,7 +115,9 @@ func (i *instanceDB) GetInstanceAccounts(ctx context.Context, domain string, max
 		q = q.Limit(limit)
 	}
 
-	err := processErrorResponse(q.Scan(ctx))
-
-	return accounts, err
+	err := q.Scan(ctx)
+	if err != nil {
+		return nil, i.conn.ProcessError(err)
+	}
+	return accounts, nil
 }

internal/db/bundb/media.go

@@ -21,7 +21,6 @@ package bundb
 import (
 	"context"
 
-	"github.com/sirupsen/logrus"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
@@ -30,8 +29,7 @@ import (
 
 type mediaDB struct {
 	config *config.Config
-	conn   *bun.DB
-	log    *logrus.Logger
+	conn   *DBConn
 }
 
 func (m *mediaDB) newMediaQ(i interface{}) *bun.SelectQuery {
@@ -47,7 +45,9 @@ func (m *mediaDB) GetAttachmentByID(ctx context.Context, id string) (*gtsmodel.M
 	q := m.newMediaQ(attachment).
 		Where("media_attachment.id = ?", id)
 
-	err := processErrorResponse(q.Scan(ctx))
-
-	return attachment, err
+	err := q.Scan(ctx)
+	if err != nil {
+		return nil, m.conn.ProcessError(err)
+	}
+	return attachment, nil
 }

internal/db/bundb/mention.go

@@ -21,8 +21,7 @@ package bundb
 import (
 	"context"
 
-	"github.com/sirupsen/logrus"
-	"github.com/superseriousbusiness/gotosocial/internal/cache"
+	"github.com/ReneKroon/ttlcache"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
@@ -31,38 +30,8 @@ import (
 
 type mentionDB struct {
 	config *config.Config
-	conn   *bun.DB
-	log    *logrus.Logger
-	cache  cache.Cache
-}
-
-func (m *mentionDB) cacheMention(id string, mention *gtsmodel.Mention) {
-	if m.cache == nil {
-		m.cache = cache.New()
-	}
-
-	if err := m.cache.Store(id, mention); err != nil {
-		m.log.Panicf("mentionDB: error storing in cache: %s", err)
-	}
-}
-
-func (m *mentionDB) mentionCached(id string) (*gtsmodel.Mention, bool) {
-	if m.cache == nil {
-		m.cache = cache.New()
-		return nil, false
-	}
-
-	mI, err := m.cache.Fetch(id)
-	if err != nil || mI == nil {
-		return nil, false
-	}
-
-	mention, ok := mI.(*gtsmodel.Mention)
-	if !ok {
-		m.log.Panicf("mentionDB: cached interface with key %s was not a mention", id)
-	}
-
-	return mention, true
+	conn   *DBConn
+	cache  *ttlcache.Cache
 }
 
 func (m *mentionDB) newMentionQ(i interface{}) *bun.SelectQuery {
@@ -74,33 +43,57 @@ func (m *mentionDB) newMentionQ(i interface{}) *bun.SelectQuery {
 		Relation("TargetAccount")
 }
 
-func (m *mentionDB) GetMention(ctx context.Context, id string) (*gtsmodel.Mention, db.Error) {
-	if mention, cached := m.mentionCached(id); cached {
-		return mention, nil
+func (m *mentionDB) getMentionCached(id string) (*gtsmodel.Mention, bool) {
+	v, ok := m.cache.Get(id)
+	if !ok {
+		return nil, false
 	}
+	return v.(*gtsmodel.Mention), true
+}
 
+func (m *mentionDB) putMentionCache(mention *gtsmodel.Mention) {
+	m.cache.Set(mention.ID, mention)
+}
+
+func (m *mentionDB) getMentionDB(ctx context.Context, id string) (*gtsmodel.Mention, db.Error) {
 	mention := &gtsmodel.Mention{}
 
 	q := m.newMentionQ(mention).
 		Where("mention.id = ?", id)
 
-	err := processErrorResponse(q.Scan(ctx))
-
-	if err == nil && mention != nil {
-		m.cacheMention(id, mention)
+	err := q.Scan(ctx)
+	if err != nil {
+		return nil, m.conn.ProcessError(err)
 	}
 
-	return mention, err
+	m.putMentionCache(mention)
+	return mention, nil
+}
+
+func (m *mentionDB) GetMention(ctx context.Context, id string) (*gtsmodel.Mention, db.Error) {
+	if mention, cached := m.getMentionCached(id); cached {
+		return mention, nil
+	}
+	return m.getMentionDB(ctx, id)
 }
 
 func (m *mentionDB) GetMentions(ctx context.Context, ids []string) ([]*gtsmodel.Mention, db.Error) {
-	mentions := []*gtsmodel.Mention{}
+	mentions := make([]*gtsmodel.Mention, 0, len(ids))
 
-	for _, i := range ids {
-		mention, err := m.GetMention(ctx, i)
-		if err != nil {
-			return nil, processErrorResponse(err)
+	for _, id := range ids {
+		// Attempt fetch from cache
+		mention, cached := m.getMentionCached(id)
+		if cached {
+			mentions = append(mentions, mention)
 		}
+
+		// Attempt fetch from DB
+		mention, err := m.getMentionDB(ctx, id)
+		if err != nil {
+			return nil, err
+		}
+
+		// Append mention
 		mentions = append(mentions, mention)
 	}
 

internal/db/bundb/notification.go

@@ -21,8 +21,7 @@ package bundb
 import (
 	"context"
 
-	"github.com/sirupsen/logrus"
-	"github.com/superseriousbusiness/gotosocial/internal/cache"
+	"github.com/ReneKroon/ttlcache"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
@@ -31,38 +30,8 @@ import (
 
 type notificationDB struct {
 	config *config.Config
-	conn   *bun.DB
-	log    *logrus.Logger
-	cache  cache.Cache
-}
-
-func (n *notificationDB) cacheNotification(id string, notification *gtsmodel.Notification) {
-	if n.cache == nil {
-		n.cache = cache.New()
-	}
-
-	if err := n.cache.Store(id, notification); err != nil {
-		n.log.Panicf("notificationDB: error storing in cache: %s", err)
-	}
-}
-
-func (n *notificationDB) notificationCached(id string) (*gtsmodel.Notification, bool) {
-	if n.cache == nil {
-		n.cache = cache.New()
-		return nil, false
-	}
-
-	nI, err := n.cache.Fetch(id)
-	if err != nil || nI == nil {
-		return nil, false
-	}
-
-	notification, ok := nI.(*gtsmodel.Notification)
-	if !ok {
-		n.log.Panicf("notificationDB: cached interface with key %s was not a notification", id)
-	}
-
-	return notification, true
+	conn   *DBConn
+	cache  *ttlcache.Cache
 }
 
 func (n *notificationDB) newNotificationQ(i interface{}) *bun.SelectQuery {
@@ -75,30 +44,30 @@ func (n *notificationDB) newNotificationQ(i interface{}) *bun.SelectQuery {
 }
 
 func (n *notificationDB) GetNotification(ctx context.Context, id string) (*gtsmodel.Notification, db.Error) {
-	if notification, cached := n.notificationCached(id); cached {
+	if notification, cached := n.getNotificationCache(id); cached {
 		return notification, nil
 	}
 
-	notification := &gtsmodel.Notification{}
-
-	q := n.newNotificationQ(notification).
-		Where("notification.id = ?", id)
-
-	err := processErrorResponse(q.Scan(ctx))
-
-	if err == nil && notification != nil {
-		n.cacheNotification(id, notification)
+	notif := &gtsmodel.Notification{}
+	err := n.getNotificationDB(ctx, id, notif)
+	if err != nil {
+		return nil, err
 	}
-
-	return notification, err
+	return notif, nil
 }
 
 func (n *notificationDB) GetNotifications(ctx context.Context, accountID string, limit int, maxID string, sinceID string) ([]*gtsmodel.Notification, db.Error) {
-	// begin by selecting just the IDs
-	notifIDs := []*gtsmodel.Notification{}
+	// Ensure reasonable
+	if limit < 0 {
+		limit = 0
+	}
+
+	// Make a guess for slice size
+	notifications := make([]*gtsmodel.Notification, 0, limit)
+
 	q := n.conn.
 		NewSelect().
-		Model(&notifIDs).
+		Model(&notifications).
 		Column("id").
 		Where("target_account_id = ?", accountID).
 		Order("id DESC")
@@ -115,22 +84,52 @@ func (n *notificationDB) GetNotifications(ctx context.Context, accountID string,
 		q = q.Limit(limit)
 	}
 
-	err := processErrorResponse(q.Scan(ctx))
+	err := q.Scan(ctx)
 	if err != nil {
-		return nil, err
+		return nil, n.conn.ProcessError(err)
 	}
 
 	// now we have the IDs, select the notifs one by one
 	// reason for this is that for each notif, we can instead get it from our cache if it's cached
-	notifications := []*gtsmodel.Notification{}
-	for _, notifID := range notifIDs {
-		notif, err := n.GetNotification(ctx, notifID.ID)
-		errP := processErrorResponse(err)
-		if errP != nil {
-			return nil, errP
+	for i, notif := range notifications {
+		// Check cache for notification
+		nn, cached := n.getNotificationCache(notif.ID)
+		if cached {
+			notifications[i] = nn
+			continue
+		}
+
+		// Check DB for notification
+		err := n.getNotificationDB(ctx, notif.ID, notif)
+		if err != nil {
+			return nil, err
 		}
-		notifications = append(notifications, notif)
 	}
 
 	return notifications, nil
 }
+
+func (n *notificationDB) getNotificationCache(id string) (*gtsmodel.Notification, bool) {
+	v, ok := n.cache.Get(id)
+	if !ok {
+		return nil, false
+	}
+	return v.(*gtsmodel.Notification), true
+}
+
+func (n *notificationDB) putNotificationCache(notif *gtsmodel.Notification) {
+	n.cache.Set(notif.ID, notif)
+}
+
+func (n *notificationDB) getNotificationDB(ctx context.Context, id string, dst *gtsmodel.Notification) error {
+	q := n.newNotificationQ(dst).
+		Where("notification.id = ?", id)
+
+	err := q.Scan(ctx)
+	if err != nil {
+		return n.conn.ProcessError(err)
+	}
+
+	n.putNotificationCache(dst)
+	return nil
+}

internal/db/bundb/relationship.go

@@ -23,7 +23,6 @@ import (
 	"database/sql"
 	"fmt"
 
-	"github.com/sirupsen/logrus"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
@@ -32,8 +31,7 @@ import (
 
 type relationshipDB struct {
 	config *config.Config
-	conn   *bun.DB
-	log    *logrus.Logger
+	conn   *DBConn
 }
 
 func (r *relationshipDB) newBlockQ(block *gtsmodel.Block) *bun.SelectQuery {
@@ -66,7 +64,7 @@ func (r *relationshipDB) IsBlocked(ctx context.Context, account1 string, account
 			Where("account_id = ?", account2)
 	}
 
-	return exists(ctx, q)
+	return r.conn.Exists(ctx, q)
 }
 
 func (r *relationshipDB) GetBlock(ctx context.Context, account1 string, account2 string) (*gtsmodel.Block, db.Error) {
@@ -76,9 +74,11 @@ func (r *relationshipDB) GetBlock(ctx context.Context, account1 string, account2
 		Where("block.account_id = ?", account1).
 		Where("block.target_account_id = ?", account2)
 
-	err := processErrorResponse(q.Scan(ctx))
-
-	return block, err
+	err := q.Scan(ctx)
+	if err != nil {
+		return nil, r.conn.ProcessError(err)
+	}
+	return block, nil
 }
 
 func (r *relationshipDB) GetRelationship(ctx context.Context, requestingAccount string, targetAccount string) (*gtsmodel.Relationship, db.Error) {
@@ -176,7 +176,7 @@ func (r *relationshipDB) IsFollowing(ctx context.Context, sourceAccount *gtsmode
 		Where("target_account_id = ?", targetAccount.ID).
 		Limit(1)
 
-	return exists(ctx, q)
+	return r.conn.Exists(ctx, q)
 }
 
 func (r *relationshipDB) IsFollowRequested(ctx context.Context, sourceAccount *gtsmodel.Account, targetAccount *gtsmodel.Account) (bool, db.Error) {
@@ -190,7 +190,7 @@ func (r *relationshipDB) IsFollowRequested(ctx context.Context, sourceAccount *g
 		Where("account_id = ?", sourceAccount.ID).
 		Where("target_account_id = ?", targetAccount.ID)
 
-	return exists(ctx, q)
+	return r.conn.Exists(ctx, q)
 }
 
 func (r *relationshipDB) IsMutualFollowing(ctx context.Context, account1 *gtsmodel.Account, account2 *gtsmodel.Account) (bool, db.Error) {
@@ -201,13 +201,13 @@ func (r *relationshipDB) IsMutualFollowing(ctx context.Context, account1 *gtsmod
 	// make sure account 1 follows account 2
 	f1, err := r.IsFollowing(ctx, account1, account2)
 	if err != nil {
-		return false, processErrorResponse(err)
+		return false, err
 	}
 
 	// make sure account 2 follows account 1
 	f2, err := r.IsFollowing(ctx, account2, account1)
 	if err != nil {
-		return false, processErrorResponse(err)
+		return false, err
 	}
 
 	return f1 && f2, nil
@@ -222,7 +222,7 @@ func (r *relationshipDB) AcceptFollowRequest(ctx context.Context, originAccountI
 		Where("account_id = ?", originAccountID).
 		Where("target_account_id = ?", targetAccountID).
 		Scan(ctx); err != nil {
-		return nil, processErrorResponse(err)
+		return nil, r.conn.ProcessError(err)
 	}
 
 	// create a new follow to 'replace' the request with
@@ -239,7 +239,7 @@ func (r *relationshipDB) AcceptFollowRequest(ctx context.Context, originAccountI
 		Model(follow).
 		On("CONFLICT ON CONSTRAINT follows_account_id_target_account_id_key DO UPDATE set uri = ?", follow.URI).
 		Exec(ctx); err != nil {
-		return nil, processErrorResponse(err)
+		return nil, r.conn.ProcessError(err)
 	}
 
 	// now remove the follow request
@@ -249,7 +249,7 @@ func (r *relationshipDB) AcceptFollowRequest(ctx context.Context, originAccountI
 		Where("account_id = ?", originAccountID).
 		Where("target_account_id = ?", targetAccountID).
 		Exec(ctx); err != nil {
-		return nil, processErrorResponse(err)
+		return nil, r.conn.ProcessError(err)
 	}
 
 	return follow, nil
@@ -261,9 +261,11 @@ func (r *relationshipDB) GetAccountFollowRequests(ctx context.Context, accountID
 	q := r.newFollowQ(&followRequests).
 		Where("target_account_id = ?", accountID)
 
-	err := processErrorResponse(q.Scan(ctx))
-
-	return followRequests, err
+	err := q.Scan(ctx)
+	if err != nil {
+		return nil, r.conn.ProcessError(err)
+	}
+	return followRequests, nil
 }
 
 func (r *relationshipDB) GetAccountFollows(ctx context.Context, accountID string) ([]*gtsmodel.Follow, db.Error) {
@@ -272,9 +274,11 @@ func (r *relationshipDB) GetAccountFollows(ctx context.Context, accountID string
 	q := r.newFollowQ(&follows).
 		Where("account_id = ?", accountID)
 
-	err := processErrorResponse(q.Scan(ctx))
-
-	return follows, err
+	err := q.Scan(ctx)
+	if err != nil {
+		return nil, r.conn.ProcessError(err)
+	}
+	return follows, nil
 }
 
 func (r *relationshipDB) CountAccountFollows(ctx context.Context, accountID string, localOnly bool) (int, db.Error) {
@@ -286,7 +290,6 @@ func (r *relationshipDB) CountAccountFollows(ctx context.Context, accountID stri
 }
 
 func (r *relationshipDB) GetAccountFollowedBy(ctx context.Context, accountID string, localOnly bool) ([]*gtsmodel.Follow, db.Error) {
-
 	follows := []*gtsmodel.Follow{}
 
 	q := r.conn.
@@ -302,11 +305,9 @@ func (r *relationshipDB) GetAccountFollowedBy(ctx context.Context, accountID str
 		q = q.Where("target_account_id = ?", accountID)
 	}
 
-	if err := q.Scan(ctx); err != nil {
-		if err == sql.ErrNoRows {
-			return follows, nil
-		}
-		return nil, processErrorResponse(err)
+	err := q.Scan(ctx)
+	if err != nil && err != sql.ErrNoRows {
+		return nil, r.conn.ProcessError(err)
 	}
 	return follows, nil
 }

internal/db/bundb/session.go

@@ -23,22 +23,19 @@ import (
 	"crypto/rand"
 	"errors"
 
-	"github.com/sirupsen/logrus"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/id"
-	"github.com/uptrace/bun"
 )
 
 type sessionDB struct {
 	config *config.Config
-	conn   *bun.DB
-	log    *logrus.Logger
+	conn   *DBConn
 }
 
 func (s *sessionDB) GetSession(ctx context.Context) (*gtsmodel.RouterSession, db.Error) {
-	rss := []*gtsmodel.RouterSession{}
+	rss := make([]*gtsmodel.RouterSession, 0, 1)
 
 	_, err := s.conn.
 		NewSelect().
@@ -47,7 +44,7 @@ func (s *sessionDB) GetSession(ctx context.Context) (*gtsmodel.RouterSession, db
 		Order("id DESC").
 		Exec(ctx)
 	if err != nil {
-		return nil, processErrorResponse(err)
+		return nil, s.conn.ProcessError(err)
 	}
 
 	if len(rss) <= 0 {
@@ -92,8 +89,8 @@ func (s *sessionDB) createSession(ctx context.Context) (*gtsmodel.RouterSession,
 		Model(rs)
 
 	_, err = q.Exec(ctx)
-
-	err = processErrorResponse(err)
-
-	return rs, err
+	if err != nil {
+		return nil, s.conn.ProcessError(err)
+	}
+	return rs, nil
 }

internal/db/bundb/status.go

@@ -24,7 +24,6 @@ import (
 	"errors"
 	"time"
 
-	"github.com/sirupsen/logrus"
 	"github.com/superseriousbusiness/gotosocial/internal/cache"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
@@ -34,38 +33,8 @@ import (
 
 type statusDB struct {
 	config *config.Config
-	conn   *bun.DB
-	log    *logrus.Logger
-	cache  cache.Cache
-}
-
-func (s *statusDB) cacheStatus(id string, status *gtsmodel.Status) {
-	if s.cache == nil {
-		s.cache = cache.New()
-	}
-
-	if err := s.cache.Store(id, status); err != nil {
-		s.log.Panicf("statusDB: error storing in cache: %s", err)
-	}
-}
-
-func (s *statusDB) statusCached(id string) (*gtsmodel.Status, bool) {
-	if s.cache == nil {
-		s.cache = cache.New()
-		return nil, false
-	}
-
-	sI, err := s.cache.Fetch(id)
-	if err != nil || sI == nil {
-		return nil, false
-	}
-
-	status, ok := sI.(*gtsmodel.Status)
-	if !ok {
-		s.log.Panicf("statusDB: cached interface with key %s was not a status", id)
-	}
-
-	return status, true
+	conn   *DBConn
+	cache  *cache.StatusCache
 }
 
 func (s *statusDB) newStatusQ(status interface{}) *bun.SelectQuery {
@@ -84,7 +53,9 @@ func (s *statusDB) newStatusQ(status interface{}) *bun.SelectQuery {
 
 func (s *statusDB) getAttachedStatuses(ctx context.Context, status *gtsmodel.Status) *gtsmodel.Status {
 	if status.InReplyToID != "" && status.InReplyTo == nil {
-		if inReplyTo, cached := s.statusCached(status.InReplyToID); cached {
+		// TODO: do we want to keep this possibly recursive strategy?
+
+		if inReplyTo, cached := s.cache.GetByID(status.InReplyToID); cached {
 			status.InReplyTo = inReplyTo
 		} else if inReplyTo, err := s.GetStatusByID(ctx, status.InReplyToID); err == nil {
 			status.InReplyTo = inReplyTo
@@ -92,7 +63,9 @@ func (s *statusDB) getAttachedStatuses(ctx context.Context, status *gtsmodel.Sta
 	}
 
 	if status.BoostOfID != "" && status.BoostOf == nil {
-		if boostOf, cached := s.statusCached(status.BoostOfID); cached {
+		// TODO: do we want to keep this possibly recursive strategy?
+
+		if boostOf, cached := s.cache.GetByID(status.BoostOfID); cached {
 			status.BoostOf = boostOf
 		} else if boostOf, err := s.GetStatusByID(ctx, status.BoostOfID); err == nil {
 			status.BoostOf = boostOf
@@ -112,29 +85,26 @@ func (s *statusDB) newFaveQ(faves interface{}) *bun.SelectQuery {
 }
 
 func (s *statusDB) GetStatusByID(ctx context.Context, id string) (*gtsmodel.Status, db.Error) {
-	if status, cached := s.statusCached(id); cached {
+	if status, cached := s.cache.GetByID(id); cached {
 		return status, nil
 	}
 
-	status := new(gtsmodel.Status)
+	status := &gtsmodel.Status{}
 
 	q := s.newStatusQ(status).
 		Where("status.id = ?", id)
 
-	err := processErrorResponse(q.Scan(ctx))
+	err := q.Scan(ctx)
 	if err != nil {
-		return nil, err
+		return nil, s.conn.ProcessError(err)
 	}
 
-	if status != nil {
-		s.cacheStatus(id, status)
-	}
-
-	return s.getAttachedStatuses(ctx, status), err
+	s.cache.Put(status)
+	return s.getAttachedStatuses(ctx, status), nil
 }
 
 func (s *statusDB) GetStatusByURI(ctx context.Context, uri string) (*gtsmodel.Status, db.Error) {
-	if status, cached := s.statusCached(uri); cached {
+	if status, cached := s.cache.GetByURI(uri); cached {
 		return status, nil
 	}
 
@@ -143,38 +113,32 @@ func (s *statusDB) GetStatusByURI(ctx context.Context, uri string) (*gtsmodel.St
 	q := s.newStatusQ(status).
 		Where("LOWER(status.uri) = LOWER(?)", uri)
 
-	err := processErrorResponse(q.Scan(ctx))
+	err := q.Scan(ctx)
 	if err != nil {
-		return nil, err
+		return nil, s.conn.ProcessError(err)
 	}
 
-	if status != nil {
-		s.cacheStatus(uri, status)
-	}
-
-	return s.getAttachedStatuses(ctx, status), err
+	s.cache.Put(status)
+	return s.getAttachedStatuses(ctx, status), nil
 }
 
-func (s *statusDB) GetStatusByURL(ctx context.Context, uri string) (*gtsmodel.Status, db.Error) {
-	if status, cached := s.statusCached(uri); cached {
+func (s *statusDB) GetStatusByURL(ctx context.Context, url string) (*gtsmodel.Status, db.Error) {
+	if status, cached := s.cache.GetByURL(url); cached {
 		return status, nil
 	}
 
 	status := &gtsmodel.Status{}
 
 	q := s.newStatusQ(status).
-		Where("LOWER(status.url) = LOWER(?)", uri)
+		Where("LOWER(status.url) = LOWER(?)", url)
 
-	err := processErrorResponse(q.Scan(ctx))
+	err := q.Scan(ctx)
 	if err != nil {
-		return nil, err
+		return nil, s.conn.ProcessError(err)
 	}
 
-	if status != nil {
-		s.cacheStatus(uri, status)
-	}
-
-	return s.getAttachedStatuses(ctx, status), err
+	s.cache.Put(status)
+	return s.getAttachedStatuses(ctx, status), nil
 }
 
 func (s *statusDB) PutStatus(ctx context.Context, status *gtsmodel.Status) db.Error {
@@ -213,14 +177,12 @@ func (s *statusDB) PutStatus(ctx context.Context, status *gtsmodel.Status) db.Er
 		_, err := tx.NewInsert().Model(status).Exec(ctx)
 		return err
 	}
-
-	return processErrorResponse(s.conn.RunInTx(ctx, nil, transaction))
+	return s.conn.ProcessError(s.conn.RunInTx(ctx, nil, transaction))
 }
 
 func (s *statusDB) GetStatusParents(ctx context.Context, status *gtsmodel.Status, onlyDirect bool) ([]*gtsmodel.Status, db.Error) {
 	parents := []*gtsmodel.Status{}
 	s.statusParent(ctx, status, &parents, onlyDirect)
-
 	return parents, nil
 }
 
@@ -318,7 +280,7 @@ func (s *statusDB) IsStatusFavedBy(ctx context.Context, status *gtsmodel.Status,
 		Where("status_id = ?", status.ID).
 		Where("account_id = ?", accountID)
 
-	return exists(ctx, q)
+	return s.conn.Exists(ctx, q)
 }
 
 func (s *statusDB) IsStatusRebloggedBy(ctx context.Context, status *gtsmodel.Status, accountID string) (bool, db.Error) {
@@ -328,7 +290,7 @@ func (s *statusDB) IsStatusRebloggedBy(ctx context.Context, status *gtsmodel.Sta
 		Where("boost_of_id = ?", status.ID).
 		Where("account_id = ?", accountID)
 
-	return exists(ctx, q)
+	return s.conn.Exists(ctx, q)
 }
 
 func (s *statusDB) IsStatusMutedBy(ctx context.Context, status *gtsmodel.Status, accountID string) (bool, db.Error) {
@@ -338,7 +300,7 @@ func (s *statusDB) IsStatusMutedBy(ctx context.Context, status *gtsmodel.Status,
 		Where("status_id = ?", status.ID).
 		Where("account_id = ?", accountID)
 
-	return exists(ctx, q)
+	return s.conn.Exists(ctx, q)
 }
 
 func (s *statusDB) IsStatusBookmarkedBy(ctx context.Context, status *gtsmodel.Status, accountID string) (bool, db.Error) {
@@ -348,7 +310,7 @@ func (s *statusDB) IsStatusBookmarkedBy(ctx context.Context, status *gtsmodel.St
 		Where("status_id = ?", status.ID).
 		Where("account_id = ?", accountID)
 
-	return exists(ctx, q)
+	return s.conn.Exists(ctx, q)
 }
 
 func (s *statusDB) GetStatusFaves(ctx context.Context, status *gtsmodel.Status) ([]*gtsmodel.StatusFave, db.Error) {
@@ -357,8 +319,11 @@ func (s *statusDB) GetStatusFaves(ctx context.Context, status *gtsmodel.Status)
 	q := s.newFaveQ(&faves).
 		Where("status_id = ?", status.ID)
 
-	err := processErrorResponse(q.Scan(ctx))
-	return faves, err
+	err := q.Scan(ctx)
+	if err != nil {
+		return nil, s.conn.ProcessError(err)
+	}
+	return faves, nil
 }
 
 func (s *statusDB) GetStatusReblogs(ctx context.Context, status *gtsmodel.Status) ([]*gtsmodel.Status, db.Error) {
@@ -367,6 +332,9 @@ func (s *statusDB) GetStatusReblogs(ctx context.Context, status *gtsmodel.Status
 	q := s.newStatusQ(&reblogs).
 		Where("boost_of_id = ?", status.ID)
 
-	err := processErrorResponse(q.Scan(ctx))
-	return reblogs, err
+	err := q.Scan(ctx)
+	if err != nil {
+		return nil, s.conn.ProcessError(err)
+	}
+	return reblogs, nil
 }

internal/db/bundb/status_test.go

@@ -59,7 +59,6 @@ func (suite *StatusTestSuite) TearDownTest() {
 func (suite *StatusTestSuite) TestGetStatusByID() {
 	status, err := suite.db.GetStatusByID(context.Background(), suite.testStatuses["local_account_1_status_1"].ID)
 	if err != nil {
-		fmt.Println(err.Error())
 		suite.FailNow(err.Error())
 	}
 	suite.NotNil(status)

internal/db/bundb/timeline.go

@@ -23,7 +23,6 @@ import (
 	"database/sql"
 	"sort"
 
-	"github.com/sirupsen/logrus"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
@@ -32,12 +31,18 @@ import (
 
 type timelineDB struct {
 	config *config.Config
-	conn   *bun.DB
-	log    *logrus.Logger
+	conn   *DBConn
 }
 
 func (t *timelineDB) GetHomeTimeline(ctx context.Context, accountID string, maxID string, sinceID string, minID string, limit int, local bool) ([]*gtsmodel.Status, db.Error) {
-	statuses := []*gtsmodel.Status{}
+	// Ensure reasonable
+	if limit < 0 {
+		limit = 0
+	}
+
+	// Make educated guess for slice size
+	statuses := make([]*gtsmodel.Status, 0, limit)
+
 	q := t.conn.
 		NewSelect().
 		Model(&statuses)
@@ -86,11 +91,21 @@ func (t *timelineDB) GetHomeTimeline(ctx context.Context, accountID string, maxI
 
 	q = q.WhereGroup(" AND ", whereGroup)
 
-	return statuses, processErrorResponse(q.Scan(ctx))
+	err := q.Scan(ctx)
+	if err != nil {
+		return nil, t.conn.ProcessError(err)
+	}
+	return statuses, nil
 }
 
 func (t *timelineDB) GetPublicTimeline(ctx context.Context, accountID string, maxID string, sinceID string, minID string, limit int, local bool) ([]*gtsmodel.Status, db.Error) {
-	statuses := []*gtsmodel.Status{}
+	// Ensure reasonable
+	if limit < 0 {
+		limit = 0
+	}
+
+	// Make educated guess for slice size
+	statuses := make([]*gtsmodel.Status, 0, limit)
 
 	q := t.conn.
 		NewSelect().
@@ -121,14 +136,23 @@ func (t *timelineDB) GetPublicTimeline(ctx context.Context, accountID string, ma
 		q = q.Limit(limit)
 	}
 
-	return statuses, processErrorResponse(q.Scan(ctx))
+	err := q.Scan(ctx)
+	if err != nil {
+		return nil, t.conn.ProcessError(err)
+	}
+	return statuses, nil
 }
 
 // TODO optimize this query and the logic here, because it's slow as balls -- it takes like a literal second to return with a limit of 20!
 // It might be worth serving it through a timeline instead of raw DB queries, like we do for Home feeds.
 func (t *timelineDB) GetFavedTimeline(ctx context.Context, accountID string, maxID string, minID string, limit int) ([]*gtsmodel.Status, string, string, db.Error) {
+	// Ensure reasonable
+	if limit < 0 {
+		limit = 0
+	}
 
-	faves := []*gtsmodel.StatusFave{}
+	// Make educated guess for slice size
+	faves := make([]*gtsmodel.StatusFave, 0, limit)
 
 	fq := t.conn.
 		NewSelect().
@@ -160,26 +184,23 @@ func (t *timelineDB) GetFavedTimeline(ctx context.Context, accountID string, max
 		return nil, "", "", db.ErrNoEntries
 	}
 
-	// map[statusID]faveID -- we need this to sort statuses by fave ID rather than their own ID
-	statusesFavesMap := map[string]string{}
-
-	in := []string{}
+	// map[statusID]faveID -- we need this to sort statuses by fave ID rather than status ID
+	statusesFavesMap := make(map[string]string, len(faves))
+	statusIDs := make([]string, 0, len(faves))
 	for _, f := range faves {
 		statusesFavesMap[f.StatusID] = f.ID
-		in = append(in, f.StatusID)
+		statusIDs = append(statusIDs, f.StatusID)
 	}
 
-	statuses := []*gtsmodel.Status{}
+	statuses := make([]*gtsmodel.Status, 0, len(statusIDs))
+
 	err = t.conn.
 		NewSelect().
 		Model(&statuses).
-		Where("id IN (?)", bun.In(in)).
+		Where("id IN (?)", bun.In(statusIDs)).
 		Scan(ctx)
 	if err != nil {
-		if err == sql.ErrNoRows {
-			return nil, "", "", db.ErrNoEntries
-		}
-		return nil, "", "", err
+		return nil, "", "", t.conn.ProcessError(err)
 	}
 
 	if len(statuses) == 0 {

internal/db/bundb/util.go

@@ -19,64 +19,9 @@
 package bundb
 
 import (
-	"context"
-	"strings"
-
-	"database/sql"
-
-	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/uptrace/bun"
 )
 
-// processErrorResponse parses the given error and returns an appropriate DBError.
-func processErrorResponse(err error) db.Error {
-	switch err {
-	case nil:
-		return nil
-	case sql.ErrNoRows:
-		return db.ErrNoEntries
-	default:
-		if strings.Contains(err.Error(), "duplicate key value violates unique constraint") {
-			return db.ErrAlreadyExists
-		}
-		return err
-	}
-}
-
-func exists(ctx context.Context, q *bun.SelectQuery) (bool, db.Error) {
-	count, err := q.Count(ctx)
-
-	exists := count != 0
-
-	err = processErrorResponse(err)
-
-	if err != nil {
-		if err == db.ErrNoEntries {
-			return false, nil
-		}
-		return false, err
-	}
-
-	return exists, nil
-}
-
-func notExists(ctx context.Context, q *bun.SelectQuery) (bool, db.Error) {
-	count, err := q.Count(ctx)
-
-	notExists := count == 0
-
-	err = processErrorResponse(err)
-
-	if err != nil {
-		if err == db.ErrNoEntries {
-			return true, nil
-		}
-		return false, err
-	}
-
-	return notExists, nil
-}
-
 // whereEmptyOrNull is a convenience function to return a bun WhereGroup that specifies
 // that the given column should be EITHER an empty string OR null.
 //