Files
tasks/common/metrics/defs.go
Michael SnowdenandGitHub c8668436e7 Add a With(Handler) method to all metricDefinition objects (#5187)
## What changed?
<!-- Describe what has changed in this PR -->
I created new structs that embed `metricDefinition` (e.g.
`histogramDefinition`), and I added a `With(Handler)` method to each of
them. I also added an example that migrates the usage of `Handler` to
this new approach, for one of each type of metric definition.

If this lands, I will also create an issue with the "good first issue"
tag to migrate all usage to the new approach. There's no need to do it
right away, though.

## Why?
<!-- Tell your future self why have you made these changes -->
Previously, usage of our `metrics.Handler` could be both redundant and
unsafe:
```
handler.Histogram( myHisto.Name(), myHisto.Unit() ).Record(...)
            │             │               └───┐
            │             │                   │
            └─────┐       └───────────┐       │
                  │                   │       │
   Redundant and Unsafe: 'Histogram'  │       │
   is specified despite knowing       │       │
   'myHisto' is a histogram. There's  │       │
   also a risk if 'myHisto.Name()'    │       │
   refers to a metric definition that │       │
   is not a histogram.                │       │
                                      └─── Redundant information
```

If you use the new `With(Handler)` method, there's no need to specify
redundant information.

## How did you test it?
<!-- How have you verified this change? Tested locally? Added a unit
test? Checked in staging env? -->
I added an `ExampleHandler` which tests all the new methods and also
serves as documentation on how to use the `Handler`, to encourage people
to use the new approach.

## Potential risks
<!-- Assuming the worst case, what can be broken when deploying this
change to production? -->
People can still use the old approach after this PR lands because we are
keeping the `Handler` interface as-is. However, we need to do that
because we can't break existing users / implementors.

## Is hotfix candidate?
<!-- Is this PR a hotfix candidate or does it require a notification to
be sent to the broader community? (Yes/No) -->
No.
2023-12-01 16:40:26 -08:00

107 lines
3.1 KiB
Go

// The MIT License
//
// Copyright (c) 2020 Temporal Technologies Inc. All rights reserved.
//
// Copyright (c) 2020 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package metrics
// types used/defined by the package
type (
MetricUnit string
// metricDefinition contains the definition for a metric
metricDefinition struct {
name string
description string
unit MetricUnit
}
histogramDefinition struct {
metricDefinition
}
counterDefinition struct {
metricDefinition
}
gaugeDefinition struct {
metricDefinition
}
timerDefinition struct {
metricDefinition
}
)
// MetricUnit supported values
// Values are pulled from https://pkg.go.dev/golang.org/x/exp/event#Unit
const (
Dimensionless = "1"
Milliseconds = "ms"
Bytes = "By"
)
func (md metricDefinition) Name() string {
return md.name
}
func (md metricDefinition) Unit() MetricUnit {
return md.unit
}
func NewTimerDef(name string, opts ...Option) timerDefinition {
return timerDefinition{globalRegistry.register(name, append(opts, WithUnit(Milliseconds))...)}
}
func NewBytesHistogramDef(name string, opts ...Option) histogramDefinition {
return histogramDefinition{globalRegistry.register(name, append(opts, WithUnit(Bytes))...)}
}
func NewDimensionlessHistogramDef(name string, opts ...Option) histogramDefinition {
return histogramDefinition{globalRegistry.register(name, append(opts, WithUnit(Dimensionless))...)}
}
func NewCounterDef(name string, opts ...Option) counterDefinition {
return counterDefinition{globalRegistry.register(name, opts...)}
}
func NewGaugeDef(name string, opts ...Option) gaugeDefinition {
return gaugeDefinition{globalRegistry.register(name, opts...)}
}
func (d histogramDefinition) With(handler Handler) HistogramIface {
return handler.Histogram(d.name, d.unit)
}
func (d counterDefinition) With(handler Handler) CounterIface {
return handler.Counter(d.name)
}
func (d gaugeDefinition) With(handler Handler) GaugeIface {
return handler.Gauge(d.name)
}
func (d timerDefinition) With(handler Handler) TimerIface {
return handler.Timer(d.name)
}