Go guide

Connect your Go application to a Redis database

Install Redis and the Redis client, then connect your Go application to a Redis database.

go-redis

go-redis provides Go clients for various flavors of Redis and a type-safe API for each Redis command.

Install

go-redis supports last two Go versions and only works with Go modules. So, first, you need to initialize a Go module:

go mod init github.com/my/repo

To install go-redis/v9:

go get github.com/redis/go-redis/v9

Connect

To connect to a Redis server:

import (
	"context"
	"fmt"
	"github.com/redis/go-redis/v9"
)

func main() {
    client := redis.NewClient(&redis.Options{
        Addr:	  "localhost:6379",
        Password: "", // no password set
        DB:		  0,  // use default DB
    })
}

Another way to connect is using a connection string.

opt, err := redis.ParseURL("redis://<user>:<pass>@localhost:6379/<db>")
if err != nil {
	panic(err)
}

client := redis.NewClient(opt)

Store and retrieve a simple string.

ctx := context.Background()

err := client.Set(ctx, "foo", "bar", 0).Err()
if err != nil {
    panic(err)
}

val, err := client.Get(ctx, "foo").Result()
if err != nil {
    panic(err)
}
fmt.Println("foo", val)

Store and retrieve a map.

session := map[string]string{"name": "John", "surname": "Smith", "company": "Redis", "age": "29"}
for k, v := range session {
    err := client.HSet(ctx, "user-session:123", k, v).Err()
    if err != nil {
        panic(err)
    }
}

userSession := client.HGetAll(ctx, "user-session:123").Val()
fmt.Println(userSession)

Connect to a Redis cluster

To connect to a Redis cluster, use NewClusterClient.

client := redis.NewClusterClient(&redis.ClusterOptions{
    Addrs: []string{":16379", ":16380", ":16381", ":16382", ":16383", ":16384"},

    // To route commands by latency or randomly, enable one of the following.
    //RouteByLatency: true,
    //RouteRandomly: true,
})

Connect to your production Redis with TLS

When you deploy your application, use TLS and follow the Redis security guidelines.

Establish a secure connection with your Redis database using this snippet.

// Load client cert
cert, err := tls.LoadX509KeyPair("redis_user.crt", "redis_user_private.key")
if err != nil {
    log.Fatal(err)
}

// Load CA cert
caCert, err := os.ReadFile("redis_ca.pem")
if err != nil {
    log.Fatal(err)
}
caCertPool := x509.NewCertPool()
caCertPool.AppendCertsFromPEM(caCert)

client := redis.NewClient(&redis.Options{
    Addr:     "my-redis.cloud.redislabs.com:6379",
    Username: "default", // use your Redis user. More info https://redis.io/docs/latest/operate/oss_and_stack/management/security/acl/
    Password: "secret", // use your Redis password
    TLSConfig: &tls.Config{
        MinVersion:   tls.VersionTLS12,
        Certificates: []tls.Certificate{cert},
        RootCAs:      caCertPool,
    },
})

//send SET command
err = client.Set(ctx, "foo", "bar", 0).Err()
if err != nil {
    panic(err)
}

//send GET command and print the value
val, err := client.Get(ctx, "foo").Result()
if err != nil {
    panic(err)
}
fmt.Println("foo", val)

dial tcp: i/o timeout

You get a dial tcp: i/o timeout error when go-redis can't connect to the Redis Server, for example, when the server is down or the port is protected by a firewall. To check if Redis Server is listening on the port, run telnet command on the host where the go-redis client is running.

telnet localhost 6379
Trying 127.0.0.1...
telnet: Unable to connect to remote host: Connection refused

If you use Docker, Istio, or any other service mesh/sidecar, make sure the app starts after the container is fully available, for example, by configuring healthchecks with Docker and holdApplicationUntilProxyStarts with Istio. For more information, see Healthcheck.

Observability

To monitor go-redis performance and trace the execution of Redis commands, you can install OpenTelemetry instrumentation:

import (
    "github.com/redis/go-redis/v9"
    "github.com/redis/go-redis/extra/redisotel/v9"
)

rdb := redis.NewClient(&redis.Options{...})

// Enable tracing instrumentation.
if err := redisotel.InstrumentTracing(rdb); err != nil {
	panic(err)
}

// Enable metrics instrumentation.
if err := redisotel.InstrumentMetrics(rdb); err != nil {
	panic(err)
}

The code above instruments Redis commands to collect traces, logs, and metrics. You can find the full example on GitHub.

OpenTelemetry is a vendor-agnostic observability framework that allows you to export data to Prometheus, Jaeger, Uptrace, and more. OpenTelemetry supports distributed tracing, metrics, and logs.

You can also use OpenTelemetry for monitoring Redis Server performance metrics, which works by periodically executing the Redis INFO command and turning results into OpenTelemetry metrics.

Learn more

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