♲ Refactor configuration to use viper with context propagation

- Replace global ConfigPath and Overrides with viper-based configuration
- Add viper.New() to create configurable viper instances
- Store viper and unmarshaled Config struct in context for testability
- Add RetrieveFromContext and AddToContext helper functions
- Update files.Append to accept context and retrieve config from it
- Update formatters.Preferred and formatters.New to accept context
- Add PersistentPreRunE in CLI to create and configure viper instance
- Support -c flag for custom config file path
- Support -v flag for config value overrides
- Update all test files to create viper and add to context
- Remove unused config types and load functions
- Add viper as dependency with automatic env var support (MYLOG_*)

formatters/new_test.go

@@ -1,13 +1,13 @@
 package formatters
 
 import (
-	"fmt"
-	"os"
+	"context"
 	"slices"
 	"testing"
 
 	"codeberg.org/danjones000/my-log/config"
 	"github.com/nalgeon/be"
+	"github.com/spf13/viper"
 )
 
 func TestKinds(t *testing.T) {
@@ -17,33 +17,25 @@ func TestKinds(t *testing.T) {
 	}
 }
 
+func setupNewTest(t *testing.T) context.Context {
+	t.Helper()
+	v := viper.New()
+	v.SetConfigType("toml")
+	v.Set("output.stdout.config.format", "plain")
+	v.Set("formatters.json.pretty_print", false)
+	return config.AddToContext(t.Context(), v)
+}
+
 func TestNewUnsupported(t *testing.T) {
-	f, err := New("nope")
+	ctx := setupNewTest(t)
+	f, err := New(ctx, "nope")
 	be.Equal(t, f, nil)
 	be.Err(t, err)
 }
 
-func TestNewCantGetConfig(t *testing.T) {
-	f, _ := os.CreateTemp("", "test")
-	oldConf := config.ConfigPath
-	config.ConfigPath = f.Name()
-	defer f.Close()
-	defer func() {
-		config.ConfigPath = oldConf
-	}()
-
-	fmt.Fprint(f, `{"not":"toml"}`)
-	form, err := New("plain")
-	be.Equal(t, form, nil)
-	be.Err(t, err)
-
-	form, err = Preferred()
-	be.Equal(t, form, nil)
-	be.Err(t, err)
-}
-
 func TestPreferred(t *testing.T) {
-	form, err := Preferred()
+	ctx := setupNewTest(t)
+	form, err := Preferred(ctx)
 	be.Err(t, err, nil)
 	be.True(t, form != nil)
 }