ctxzap

Documentation

Overview

`ctxzap` is a ctxlogger that is backed by Zap

It accepts a user-configured `zap.Logger` that will be used for logging. The same `zap.Logger` will be populated into the `context.Context` passed into gRPC handler code.

You can use `ctxzap.Extract` to log into a request-scoped `zap.Logger` instance in your handler code.

As `ctxzap.Extract` will iterate all tags on from `grpc_ctxtags` it is therefore expensive so it is advised that you extract once at the start of the function from the context and reuse it for the remainder of the function (see examples).

Please see examples and tests for examples of use.

Index

• func AddFields(ctx context.Context, fields ...zapcore.Field)
• func Extract(ctx context.Context) *zap.Logger
• func TagsToFields(ctx context.Context) []zapcore.Field
• func ToContext(ctx context.Context, logger *zap.Logger) context.Context

Examples

• Extract (Unary)

Functions

func AddFields

func AddFields(ctx context.Context, fields ...zapcore.Field)

AddFields adds zap fields to the logger.

func Extract

func Extract(ctx context.Context) *zap.Logger

Extract takes the call-scoped Logger from grpc_zap middleware.

It always returns a Logger that has all the grpc_ctxtags updated.

Example (Unary)

Simple unary handler that adds custom fields to the requests's context. These will be used for all log statements.

package main

import (
	"context"

	"github.com/grpc-ecosystem/go-grpc-middleware/logging/zap/ctxzap"
	"github.com/grpc-ecosystem/go-grpc-middleware/tags"
	pb_testproto "github.com/grpc-ecosystem/go-grpc-middleware/testing/testproto"
	"go.uber.org/zap"
)

var zapLogger *zap.Logger

// Simple unary handler that adds custom fields to the requests's context. These will be used for all log statements.
func main() {
	_ = func(ctx context.Context, ping *pb_testproto.PingRequest) (*pb_testproto.PingResponse, error) {
		// Add fields the ctxtags of the request which will be added to all extracted loggers.
		grpc_ctxtags.Extract(ctx).Set("custom_tags.string", "something").Set("custom_tags.int", 1337)

		// Extract a single request-scoped zap.Logger and log messages.
		l := ctxzap.Extract(ctx)
		l.Info("some ping")
		l.Info("another ping")
		return &pb_testproto.PingResponse{Value: ping.Value}, nil
	}
}

func TagsToFields

func TagsToFields(ctx context.Context) []zapcore.Field

TagsToFields transforms the Tags on the supplied context into zap fields.

func ToContext

func ToContext(ctx context.Context, logger *zap.Logger) context.Context

ToContext adds the zap.Logger to the context for extraction later. Returning the new context that has been created.