From ad96d1969e343aad69154d1baba1107480f2afbf Mon Sep 17 00:00:00 2001
From: Vladimir Mihailenco <vladimir.webdev@gmail.com>
Date: Sat, 5 Sep 2020 12:36:22 +0300
Subject: [PATCH] Extract redisext to separate Go module

---
 README.md        |   1 +
 redisext/otel.go | 120 -----------------------------------------------
 2 files changed, 1 insertion(+), 120 deletions(-)
 delete mode 100644 redisext/otel.go

diff --git a/README.md b/README.md
index 77313f9..2eace5d 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,7 @@
 
 ## Ecosystem
 
+- [redisext](https://github.com/go-redis/redisext) - tracing using OpenTelemetryHook.
 - [Redis Cache](https://github.com/go-redis/cache).
 - [Rate limiting](https://github.com/go-redis/redis_rate).
 - [Distributed Locks](https://github.com/bsm/redislock).
diff --git a/redisext/otel.go b/redisext/otel.go
deleted file mode 100644
index d956a0f..0000000
--- a/redisext/otel.go
+++ /dev/null
@@ -1,120 +0,0 @@
-package redisext
-
-import (
-	"context"
-	"strings"
-
-	"github.com/go-redis/redis/v8"
-	"github.com/go-redis/redis/v8/internal"
-	"go.opentelemetry.io/otel/api/global"
-	"go.opentelemetry.io/otel/api/trace"
-	"go.opentelemetry.io/otel/label"
-)
-
-type OpenTelemetryHook struct{}
-
-var _ redis.Hook = OpenTelemetryHook{}
-
-func (OpenTelemetryHook) BeforeProcess(ctx context.Context, cmd redis.Cmder) (context.Context, error) {
-	if !trace.SpanFromContext(ctx).IsRecording() {
-		return ctx, nil
-	}
-
-	b := make([]byte, 32)
-	b = appendCmd(b, cmd)
-
-	tracer := global.Tracer("github.com/go-redis/redis")
-	ctx, span := tracer.Start(ctx, cmd.FullName())
-	span.SetAttributes(
-		label.String("db.system", "redis"),
-		label.String("redis.cmd", internal.String(b)),
-	)
-
-	return ctx, nil
-}
-
-func (OpenTelemetryHook) AfterProcess(ctx context.Context, cmd redis.Cmder) error {
-	span := trace.SpanFromContext(ctx)
-	if err := cmd.Err(); err != nil {
-		_ = internal.RecordError(ctx, err)
-	}
-	span.End()
-	return nil
-}
-
-func (OpenTelemetryHook) BeforeProcessPipeline(ctx context.Context, cmds []redis.Cmder) (context.Context, error) {
-	if !trace.SpanFromContext(ctx).IsRecording() {
-		return ctx, nil
-	}
-
-	const numCmdLimit = 100
-	const numNameLimit = 10
-
-	seen := make(map[string]struct{}, len(cmds))
-	unqNames := make([]string, 0, len(cmds))
-
-	b := make([]byte, 0, 32*len(cmds))
-
-	for i, cmd := range cmds {
-		if i > numCmdLimit {
-			break
-		}
-
-		if i > 0 {
-			b = append(b, '\n')
-		}
-		b = appendCmd(b, cmd)
-
-		if len(unqNames) >= numNameLimit {
-			continue
-		}
-
-		name := cmd.FullName()
-		if _, ok := seen[name]; !ok {
-			seen[name] = struct{}{}
-			unqNames = append(unqNames, name)
-		}
-	}
-
-	tracer := global.Tracer("github.com/go-redis/redis")
-	ctx, span := tracer.Start(ctx, "pipeline "+strings.Join(unqNames, " "))
-	span.SetAttributes(
-		label.String("db.system", "redis"),
-		label.Int("redis.num_cmd", len(cmds)),
-		label.String("redis.cmds", internal.String(b)),
-	)
-
-	return ctx, nil
-}
-
-func (OpenTelemetryHook) AfterProcessPipeline(ctx context.Context, cmds []redis.Cmder) error {
-	span := trace.SpanFromContext(ctx)
-	if err := cmds[0].Err(); err != nil {
-		_ = internal.RecordError(ctx, err)
-	}
-	span.End()
-	return nil
-}
-
-func appendCmd(b []byte, cmd redis.Cmder) []byte {
-	const lenLimit = 64
-
-	for i, arg := range cmd.Args() {
-		if i > 0 {
-			b = append(b, ' ')
-		}
-
-		start := len(b)
-		b = internal.AppendArg(b, arg)
-		if len(b)-start > lenLimit {
-			b = append(b[:start+lenLimit], "..."...)
-		}
-	}
-
-	if err := cmd.Err(); err != nil {
-		b = append(b, ": "...)
-		b = append(b, err.Error()...)
-	}
-
-	return b
-}