opentelemetry (This is a community driven project)

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Opentelemetry for Hertz

Feature

Provider

• Out-of-the-box default opentelemetry provider
• Support setting via environment variables

Instrumentation

Tracing

• Support server and client hertz http tracing
• Support automatic transparent transmission of peer service through http headers

Metrics

• Support hertz http metrics [R.E.D]
• Support service topology map metrics [Service Topology Map]
• Support go runtime metrics

Logging

• Extend hertz logger based on logrus
• Implement tracing auto associated logs

Configuration via environment variables

• Exporter
• SDK

Server usage

import (
    // ...
    "github.com/hertz-contrib/obs-opentelemetry/provider"
    hertztracing "github.com/hertz-contrib/obs-opentelemetry/tracing"
)


func main()  {
    serviceName := "echo"

    p := provider.NewOpenTelemetryProvider(
        provider.WithServiceName(serviceName),
        provider.WithExportEndpoint("localhost:4317"),
        provider.WithInsecure(),
    )
    defer p.Shutdown(context.Background())

    tracer, cfg := hertztracing.NewServerTracer()
    h := server.Default(tracer)
    h.Use(hertztracing.ServerMiddleware(cfg))

    // ...

    h.Spin()
}

Client usage

import (
    // ...
    "github.com/hertz-contrib/obs-opentelemetry/provider"
    hertztracing "github.com/hertz-contrib/obs-opentelemetry/tracing"
)

func main(){
    serviceName := "echo-client"

    p := provider.NewOpenTelemetryProvider(
        provider.WithServiceName(serviceName),
        provider.WithExportEndpoint("localhost:4317"),
        provider.WithInsecure(),
    )
    defer p.Shutdown(context.Background())

    c, _ := client.NewClient()
    c.Use(hertztracing.ClientMiddleware())

    // ...

}

Tracing associated Logs

set logger impl

import (
    hertzlogrus "github.com/hertz-contrib/obs-opentelemetry/logging/logrus"
)

func init()  {
    hlog.SetLogger(hertzlogrus.NewLogger())
    hlog.SetLevel(hlog.LevelDebug)

}

You need to configure the tracing middleware in the above example at the same time. If you do not need to report the tracing, you can refer to issue

log with context

h.GET("/ping", func(c context.Context, ctx *app.RequestContext) {
    req := &api.Request{Message: "my request"}
    resp, err := client.Echo(c, req)
    if err != nil {
        hlog.Errorf(err.Error())
    }
    hlog.CtxDebugf(c, "message received successfully: %s", req.Message)
    ctx.JSON(consts.StatusOK, resp)
})

view log

{"level":"debug","msg":"message received successfully: my request","span_id":"445ef16484a171b8","time":"2022-07-04T06:27:35+08:00","trace_flags":"01","trace_id":"e9e579b32c9d6b0598f8f33d65689e06"}

Example

Executable Example

Supported Metrics

HTTP Request Metrics

Hertz Server

Below is a table of HTTP server metric instruments.

Name	Instrument Type	Unit	Unit	Description
http.server.duration	Histogram	milliseconds	ms	measures the duration inbound HTTP requests
http.server.request_count	Counter	count	count	measures the incoming request count total

Hertz Client

Below is a table of HTTP client metric instruments.

Name	Instrument Type (*)	Unit	Unit (UCUM)	Description
http.client.duration	Histogram	milliseconds	ms	measures the duration outbound HTTP requests
http.client.request_count	Counter	count	count	measures the client request count total

R.E.D

The RED Method defines the three key metrics you should measure for every microservice in your architecture. We can calculate RED based on http.server.duration.

Rate

the number of requests, per second, you services are serving.

eg: QPS

sum(rate(http_server_request_count_total{}[5m])) by (service_name, http_method)

Errors

the number of failed requests per second.

eg: Error ratio

sum(rate(http_server_request_count_total{status_code="Error"}[5m])) by (service_name, http_method) / sum(rate(http_server_request_count_total{}[5m])) by (service_name, http_method)

Duration

distributions of the amount of time each request takes

eg: P99 Latency

histogram_quantile(0.99, sum(rate(http_server_duration_bucket{}[5m])) by (le, service_name, http_method))

Service Topology Map

The http.server.duration will record the peer service and the current service dimension. Based on this dimension, we can aggregate the service topology map

sum(rate(http_server_request_count_total{}[5m])) by (service_name, peer_service)

Runtime Metrics

Name	Instrument	Unit	Unit (UCUM))	Description
process.runtime.go.cgo.calls	Sum	-	-	Number of cgo calls made by the current process.
process.runtime.go.gc.count	Sum	-	-	Number of completed garbage collection cycles.
process.runtime.go.gc.pause_ns	Histogram	nanosecond	ns	Amount of nanoseconds in GC stop-the-world pauses.
process.runtime.go.gc.pause_total_ns	Histogram	nanosecond	ns	Cumulative nanoseconds in GC stop-the-world pauses since the program started.
process.runtime.go.goroutines	Gauge	-	-	measures duration of outbound HTTP Request.
process.runtime.go.lookups	Sum	-	-	Number of pointer lookups performed by the runtime.
process.runtime.go.mem.heap_alloc	Gauge	bytes	bytes	Bytes of allocated heap objects.
process.runtime.go.mem.heap_idle	Gauge	bytes	bytes	Bytes in idle (unused) spans.
process.runtime.go.mem.heap_inuse	Gauge	bytes	bytes	Bytes in in-use spans.
process.runtime.go.mem.heap_objects	Gauge	-	-	Number of allocated heap objects.
process.runtime.go.mem.live_objects	Gauge	-	-	Number of live objects is the number of cumulative Mallocs - Frees.
process.runtime.go.mem.heap_released	Gauge	bytes	bytes	Bytes of idle spans whose physical memory has been returned to the OS.
process.runtime.go.mem.heap_sys	Gauge	bytes	bytes	Bytes of idle spans whose physical memory has been returned to the OS.
runtime.uptime	Sum	ms	ms	Milliseconds since application was initialized.

Compatibility

The sdk of OpenTelemetry is fully compatible with 1.X opentelemetry-go. see

maintained by: CoderPoet

Dependencies

Library/Framework	Versions	Notes
go.opentelemetry.io/otel	v1.9.0
go.opentelemetry.io/otel/trace	v1.9.0
go.opentelemetry.io/otel/metric	v0.31.0
go.opentelemetry.io/contrib/instrumentation/runtime	v0.30.0
hertz	v0.4.1