Support metrics report API for plugin and implement runtime metrics report (#66)

Author: mrproliu

Diff for: .github/workflows/plugin-tests.yaml

@@ -80,6 +80,7 @@ jobs:
           - mongo
           - mysql
           - plugin_exclusion
+          - runtime_metrics
     steps:
       - uses: actions/checkout@v2
         with:

Diff for: .golangci.yml

@@ -93,9 +93,10 @@ linters:
     - typecheck
     - unconvert
     - unparam
-    - unused
     - varcheck
     - whitespace
+  disable:
+    - unused
 
 service:
   golangci-lint-version: 1.20.x

Diff for: agent/core/compile.go

@@ -29,6 +29,8 @@ import (
 	_ "reflect"
 	_ "runtime"
 	_ "runtime/debug"
+	_ "runtime/metrics"
+	_ "sort"
 	_ "strconv"
 	_ "strings"
 	_ "sync"

Diff for: docs/en/development-and-contribution/development-guide.md

@@ -452,6 +452,87 @@ Typically, use APIs as following to control or switch the context:
 2. Propagate the snapshot context to any other goroutine in your plugin.
 3. Use `tracing.ContinueContext(snapshot)` to continue the snapshot context in the target goroutine.
 
+### Meter API
+
+The Meter API is used to record the metrics of the target program, and currently supports the following methods:
+
+```go
+// NewCounter creates a new counter metrics.
+// name is the name of the metrics
+// opts is the options for the metrics
+func NewCounter(name string, opts ...Opt) Counter
+
+// NewGauge creates a new gauge metrics.
+// name is the name of the metrics
+// getter is the function to get the value of the gauge meter
+// opts is the options for the metrics
+func NewGauge(name string, getter func() float64, opts ...Opt) Gauge
+
+// NewHistogram creates a new histogram metrics.
+// name is the name of the metrics
+// steps is the buckets of the histogram
+// opts is the options for the metrics
+func NewHistogram(name string, steps []float64, opts ...Opt) Histogram
+
+// NewHistogramWithMinValue creates a new histogram metrics.
+// name is the name of the metrics
+// minVal is the min value of the histogram bucket
+// steps is the buckets of the histogram
+// opts is the options for the metrics
+func NewHistogramWithMinValue(name string, minVal float64, steps []float64, opts ...Opt) Histogram
+
+// RegisterBeforeCollectHook registers a hook function which will be called before metrics collect.
+func RegisterBeforeCollectHook(f func())
+```
+
+#### Meter Option
+
+The Meter Options can be passed when creating a Meter to configure the information in the Meter.
+
+```go
+// WithLabel adds a label to the metrics.
+func WithLabel(key, value string) Opt
+```
+
+#### Meter Type
+
+##### Counter
+
+Counter is a cumulative metric that represents a single monotonically increasing counter whose value can only increase.
+
+```go
+type Counter interface {
+	// Get returns the current value of the counter.
+	Get() float64
+	// Inc increments the counter with value.
+	Inc(val float64)
+}
+```
+
+##### Gauge
+
+Gauge is a metric that represents a single numerical value that can arbitrarily go up and down.
+
+```go
+type Gauge interface {
+    // Get returns the current value of the gauge.
+    Get() float64
+}
+```
+
+##### Histogram
+
+Histogram is a metric that represents the distribution of a set of values.
+
+```go
+type Histogram interface {
+	// Observe find the value associate bucket and add 1.
+	Observe(val float64)
+	// ObserveWithCount find the value associate bucket and add specific count.
+	ObserveWithCount(val float64, count int64)
+}
+```
+
 ## Import Plugin
 
 Once you have finished developing the plugin, you need to import the completed module into the Agent program and [define it in the corresponding file](../../../tools/go-agent/instrument/plugins/register.go). 

Diff for: go.work

@@ -15,6 +15,7 @@ use (
 	./plugins/microv4
 	./plugins/mongo
 	./plugins/sql
+	./plugins/runtimemetrics
 
 	./test/benchmark-codebase/consumer
 	./test/benchmark-codebase/provider
@@ -34,6 +35,7 @@ use (
 	./test/plugins/scenarios/mysql
 
 	./test/plugins/scenarios/plugin_exclusion
+	./test/plugins/scenarios/runtime_metrics
 
 	./tools/go-agent
 

Diff for: plugins/core/context.go

@@ -25,6 +25,7 @@ var (
 	SetGlobalOperator = func(interface{}) {}
 	GetGlobalOperator = func() interface{} { return nil }
 	GetInitNotify     = func() []func() { return nil }
+	MetricsObtain     = func() ([]interface{}, []func()) { return nil, nil }
 )
 
 type ContextSnapshoter interface {

Diff for: plugins/core/instrument/enhance.go

@@ -24,6 +24,7 @@ type EnhanceType int
 var (
 	EnhanceTypeMethod EnhanceType = 1
 	EnhanceTypeStruct EnhanceType = 2
+	EnhanceTypeForce  EnhanceType = 3
 )
 
 type MethodFilterOption func(decl *dst.FuncDecl, files []*dst.File) bool
@@ -35,6 +36,8 @@ type EnhanceMatcher struct {
 	Receiver      string
 	MethodFilters []MethodFilterOption
 	StructFilters []StructFilterOption
+
+	ForceEnhance bool
 }
 
 // NewStaticMethodEnhance creates a new EnhanceMatcher for static method.
@@ -52,6 +55,10 @@ func NewStructEnhance(name string, filters ...StructFilterOption) *EnhanceMatche
 	return &EnhanceMatcher{Type: EnhanceTypeStruct, Name: name, StructFilters: filters}
 }
 
+func NewForceEnhance() *EnhanceMatcher {
+	return &EnhanceMatcher{Type: EnhanceTypeForce, ForceEnhance: true}
+}
+
 func verifyTypeName(exp dst.Expr, val string) bool {
 	data := generateTypeNameByExp(exp)
 	return data == val