LMOtelFY

Let Me OTel(Open Telemetry) For You

What this program does?

It will look for two situations:

• Exported functions that have context.Context as a parameter.
• HTTP handlers

And create:

• Start() new span made by "package.function name".
• defer the span End()
• call span.RecordError(err) when error is handled in the function.
• Add the imports needed

Examples

This code:

pakage samples

import (
	"context"
	"errors"
	"log"
	"net/http"
)

func H(w http.ResponseWriter, r *http.Request) {
	 ...
	if err != nil {
		log.Println(err.Error())
		w.WriteHeader(http.StatusUnauthorized)
		return
	}
 ...
}

func C(ctx context.Context) error {
	...
	if err != nil {
		return err
	}
	...
}

will turn into this:

pakage samples

import (
	"context"
	"errors"
	"github.com/example/extensions/telemetry" // New import needed
	"log"
	"net/http"
)

func H(w http.ResponseWriter, r *http.Request) {
	ctx, span := telemetry.FromContext(ctx).Start(ctx, "samples.H")
	defer span.End()
	...
	if err != nil {
		span.RecordError(err)
		log.Println(err.Error())
		w.WriteHeader(http.StatusUnauthorized)
		return
	}
  ...
}

func C(ctx context.Context) error {
	ctx, span := telemetry.FromContext(ctx).Start(ctx, "samples.C")
	defer span.End()
	...
	if err != nil {
		span.RecordError(err)
		return err
	}
  ...
}

Params

• --dry-run
  • when dry run is true the program will modify the files found
  • default: true
• --path
  • What path to read?
  • default: "."
• --import
  • Where is your telemetry functions?
  • default: "github.com/example/extensions/telemetry"
• --allowed-dirs
  • The list of dir fragments allowed
  • default: "samples"
• --disallowed-dirs
  • The list of dir fragments disallowed
  • default: "."