tracing

trace requests using opentracing specification, Download:

go get -u github.com/gin-contrib/opengintracing

See opentracing/opentracing-go for more information.

Usage

For example you have architecture like this

To start requests tracing you have to:

• On "API Gateway": start span, inject headers and pass it to services

package main
import (
    ...
    "github.com/gin-gonic/gin"
    "github.com/gin-contrib/opengintracing"
    "github.com/opentracing/opentracing-go"
    ...
)

var trace = /* setup tracer */

func main() {
    ...
    app := gin.Default()

    app.POST("/service1",
        opengintracing.NewSpan(trace, "forward to service 1"),
        opengintracing.InjectToHeaders(trace, true),
        service1handler)
    app.POST("/service2",
        opengintracing.NewSpan(trace, "forward to service 2"),
        opengintracing.InjectToHeaders(trace, true),
        service2handler)
    ...
}

• On "Service 1", "Service 2" start span inherited from "API Gateway"`s span

package main
import (
    ...
    "github.com/gin-gonic/gin"
    "github.com/gin-contrib/opengintracing"
    "github.com/opentracing/opentracing-go"
    ...
)

var trace = /* setup tracer */

func main() {
    ...
    refFunc := opentracing.FollowsFrom
    app := gin.Default()

    app.POST("",
        opengintracing.SpanFromHeaders(trace, "operation", refFunc, true),
        // don`t forget to inject if you want continue tracing in other service
        opengintracing.InjectToHeaders(trace, true),
        handler)
    ...
}

Also don`t forget to forward headers from "Service 1" to "Service 3"

• On "Service 3" injecting to headers is not required

package main
import (
    ...
    "github.com/gin-gonic/gin"
    "github.com/gin-contrib/opengintracing"
    "github.com/opentracing/opentracing-go"
    ...
)

var trace = /* setup tracer */

func main() {
    ...
    refFunc := opentracing.ChildOf
    app := gin.Default()

    app.POST("",
        opengintracing.SpanFromHeaders(trace, "operation", refFunc, true),
        handler)
    ...
}

TODO

• add code sample
• maybe add sample with SpanFromContext
• add buildable example (needed simple logging tracer)