9045b79bc2
This PR modifies how the metrics library handles `Enabled`: previously, the package `init` decided whether to serve real metrics or just dummy-types. This has several drawbacks: - During pkg init, we need to determine whether metrics are enabled or not. So we first hacked in a check if certain geth-specific commandline-flags were enabled. Then we added a similar check for geth-env-vars. Then we almost added a very elaborate check for toml-config-file, plus toml parsing. - Using "real" types and dummy types interchangeably means that everything is hidden behind interfaces. This has a performance penalty, and also it just adds a lot of code. This PR removes the interface stuff, uses concrete types, and allows for the setting of Enabled to happen later. It is still assumed that `metrics.Enable()` is invoked early on. The somewhat 'heavy' operations, such as ticking meters and exp-decay, now checks the enable-flag to prevent resource leak. The change may be large, but it's mostly pretty trivial, and from the last time I gutted the metrics, I ensured that we have fairly good test coverage. --------- Co-authored-by: Felix Lange <fjl@twurst.com>
51 lines
1.3 KiB
Go
51 lines
1.3 KiB
Go
package metrics
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import (
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"math"
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"sync/atomic"
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)
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// GetOrRegisterGaugeFloat64 returns an existing GaugeFloat64 or constructs and registers a
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// new GaugeFloat64.
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func GetOrRegisterGaugeFloat64(name string, r Registry) *GaugeFloat64 {
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if nil == r {
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r = DefaultRegistry
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}
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return r.GetOrRegister(name, NewGaugeFloat64()).(*GaugeFloat64)
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}
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// GaugeFloat64Snapshot is a read-only copy of a GaugeFloat64.
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type GaugeFloat64Snapshot float64
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// Value returns the value at the time the snapshot was taken.
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func (g GaugeFloat64Snapshot) Value() float64 { return float64(g) }
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// NewGaugeFloat64 constructs a new GaugeFloat64.
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func NewGaugeFloat64() *GaugeFloat64 {
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return new(GaugeFloat64)
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}
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// NewRegisteredGaugeFloat64 constructs and registers a new GaugeFloat64.
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func NewRegisteredGaugeFloat64(name string, r Registry) *GaugeFloat64 {
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c := NewGaugeFloat64()
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if nil == r {
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r = DefaultRegistry
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}
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r.Register(name, c)
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return c
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}
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// GaugeFloat64 hold a float64 value that can be set arbitrarily.
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type GaugeFloat64 atomic.Uint64
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// Snapshot returns a read-only copy of the gauge.
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func (g *GaugeFloat64) Snapshot() GaugeFloat64Snapshot {
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v := math.Float64frombits((*atomic.Uint64)(g).Load())
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return GaugeFloat64Snapshot(v)
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}
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// Update updates the gauge's value.
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func (g *GaugeFloat64) Update(v float64) {
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(*atomic.Uint64)(g).Store(math.Float64bits(v))
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}
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