[chore] Add Go runtime and host metrics (#4137)

Daenney is a dummy and forgot to add these when he revamped the OTEL stuff.

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4137
Co-authored-by: Daenney <daenney@noreply.codeberg.org>
Co-committed-by: Daenney <daenney@noreply.codeberg.org>

vendor/go.opentelemetry.io/contrib/instrumentation/runtime/options.go

@@ -0,0 +1,99 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package runtime // import "go.opentelemetry.io/contrib/instrumentation/runtime"
+
+import (
+	"time"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/metric"
+)
+
+// config contains optional settings for reporting runtime metrics.
+type config struct {
+	// MinimumReadMemStatsInterval sets the minimum interval
+	// between calls to runtime.ReadMemStats().  Negative values
+	// are ignored.
+	MinimumReadMemStatsInterval time.Duration
+
+	// MeterProvider sets the metric.MeterProvider.  If nil, the global
+	// Provider will be used.
+	MeterProvider metric.MeterProvider
+}
+
+// Option supports configuring optional settings for runtime metrics.
+type Option interface {
+	apply(*config)
+}
+
+// ProducerOption supports configuring optional settings for runtime metrics using a
+// metric producer in addition to standard instrumentation.
+type ProducerOption interface {
+	Option
+	applyProducer(*config)
+}
+
+// DefaultMinimumReadMemStatsInterval is the default minimum interval
+// between calls to runtime.ReadMemStats().  Use the
+// WithMinimumReadMemStatsInterval() option to modify this setting in
+// Start().
+const DefaultMinimumReadMemStatsInterval time.Duration = 15 * time.Second
+
+// WithMinimumReadMemStatsInterval sets a minimum interval between calls to
+// runtime.ReadMemStats(), which is a relatively expensive call to make
+// frequently.  This setting is ignored when `d` is negative.
+func WithMinimumReadMemStatsInterval(d time.Duration) Option {
+	return minimumReadMemStatsIntervalOption(d)
+}
+
+type minimumReadMemStatsIntervalOption time.Duration
+
+func (o minimumReadMemStatsIntervalOption) apply(c *config) {
+	if o >= 0 {
+		c.MinimumReadMemStatsInterval = time.Duration(o)
+	}
+}
+
+func (o minimumReadMemStatsIntervalOption) applyProducer(c *config) { o.apply(c) }
+
+// WithMeterProvider sets the Metric implementation to use for
+// reporting.  If this option is not used, the global metric.MeterProvider
+// will be used.  `provider` must be non-nil.
+func WithMeterProvider(provider metric.MeterProvider) Option {
+	return metricProviderOption{provider}
+}
+
+type metricProviderOption struct{ metric.MeterProvider }
+
+func (o metricProviderOption) apply(c *config) {
+	if o.MeterProvider != nil {
+		c.MeterProvider = o.MeterProvider
+	}
+}
+
+// newConfig computes a config from the supplied Options.
+func newConfig(opts ...Option) config {
+	c := config{
+		MeterProvider: otel.GetMeterProvider(),
+	}
+	for _, opt := range opts {
+		opt.apply(&c)
+	}
+	if c.MinimumReadMemStatsInterval <= 0 {
+		c.MinimumReadMemStatsInterval = DefaultMinimumReadMemStatsInterval
+	}
+	return c
+}
+
+// newConfig computes a config from the supplied ProducerOptions.
+func newProducerConfig(opts ...ProducerOption) config {
+	c := config{}
+	for _, opt := range opts {
+		opt.applyProducer(&c)
+	}
+	if c.MinimumReadMemStatsInterval <= 0 {
+		c.MinimumReadMemStatsInterval = DefaultMinimumReadMemStatsInterval
+	}
+	return c
+}