feat: add functionality to get values from redis commands (influxdata…

…#8196)

go.mod

@@ -50,7 +50,7 @@ require (
 	github.com/glinton/ping v0.1.4-0.20200311211934-5ac87da8cd96
 	github.com/go-logfmt/logfmt v0.4.0
 	github.com/go-ole/go-ole v1.2.1 // indirect
-	github.com/go-redis/redis v6.12.0+incompatible
+	github.com/go-redis/redis v6.15.9+incompatible
 	github.com/go-sql-driver/mysql v1.5.0
 	github.com/goburrow/modbus v0.1.0
 	github.com/goburrow/serial v0.1.0 // indirect

go.sum

@@ -214,8 +214,8 @@ github.com/go-openapi/jsonpointer v0.0.0-20160704185906-46af16f9f7b1/go.mod h1:+
 github.com/go-openapi/jsonreference v0.0.0-20160704190145-13c6e3589ad9/go.mod h1:W3Z9FmVs9qj+KR4zFKmDPGiLdk1D9Rlm7cyMvf57TTg=
 github.com/go-openapi/spec v0.0.0-20160808142527-6aced65f8501/go.mod h1:J8+jY1nAiCcj+friV/PDoE1/3eeccG9LYBs0tYvLOWc=
 github.com/go-openapi/swag v0.0.0-20160704191624-1d0bd113de87/go.mod h1:DXUve3Dpr1UfpPtxFw+EFuQ41HhCWZfha5jSVRG7C7I=
-github.com/go-redis/redis v6.12.0+incompatible h1:s+64XI+z/RXqGHz2fQSgRJOEwqqSXeX3dliF7iVkMbE=
-github.com/go-redis/redis v6.12.0+incompatible/go.mod h1:NAIEuMOZ/fxfXJIrKDQDz8wamY7mA7PouImQ2Jvg6kA=
+github.com/go-redis/redis v6.15.9+incompatible h1:K0pv1D7EQUjfyoMql+r/jZqCLizCGKFlFgcHWWmHQjg=
+github.com/go-redis/redis v6.15.9+incompatible/go.mod h1:NAIEuMOZ/fxfXJIrKDQDz8wamY7mA7PouImQ2Jvg6kA=
 github.com/go-sql-driver/mysql v1.5.0 h1:ozyZYNQW3x3HtqT1jira07DN2PArx2v7/mN66gGcHOs=
 github.com/go-sql-driver/mysql v1.5.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=

plugins/inputs/redis/README.md

@@ -14,6 +14,11 @@
   ## If no servers are specified, then localhost is used as the host.
   ## If no port is specified, 6379 is used
   servers = ["tcp://localhost:6379"]
+  ## Optional. Specify redis commands to retrieve values
+  # [[inputs.redis.commands]]
+  # command = ["get", "sample-key"]
+  # field = "sample-key-value"
+  # type = "string"
 
   ## specify server password
   # password = "s#cr@t%"

plugins/inputs/redis/redis.go

@@ -17,7 +17,14 @@ import (
 	"github.com/influxdata/telegraf/plugins/inputs"
 )
 
+type RedisCommand struct {
+	Command []interface{}
+	Field   string
+	Type    string
+}
+
 type Redis struct {
+	Commands []*RedisCommand
 	Servers  []string
 	Password string
 	tls.ClientConfig
@@ -29,6 +36,7 @@ type Redis struct {
 }
 
 type Client interface {
+	Do(returnType string, args ...interface{}) (interface{}, error)
 	Info() *redis.StringCmd
 	BaseTags() map[string]string
 }
@@ -38,6 +46,21 @@ type RedisClient struct {
 	tags   map[string]string
 }
 
+func (r *RedisClient) Do(returnType string, args ...interface{}) (interface{}, error) {
+	rawVal := r.client.Do(args...)
+
+	switch returnType {
+	case "integer":
+		return rawVal.Int64()
+	case "string":
+		return rawVal.String()
+	case "float":
+		return rawVal.Float64()
+	default:
+		return rawVal.String()
+	}
+}
+
 func (r *RedisClient) Info() *redis.StringCmd {
 	return r.client.Info("ALL")
 }
@@ -64,6 +87,12 @@ var sampleConfig = `
   ## If no port is specified, 6379 is used
   servers = ["tcp://localhost:6379"]
 
+  ## Optional. Specify redis commands to retrieve values
+  # [[inputs.redis.commands]]
+  # command = ["get", "sample-key"]
+  # field = "sample-key-value"
+  # type = "string"
+
   ## specify server password
   # password = "s#cr@t%"
 
@@ -179,13 +208,30 @@ func (r *Redis) Gather(acc telegraf.Accumulator) error {
 		go func(client Client) {
 			defer wg.Done()
 			acc.AddError(r.gatherServer(client, acc))
+			acc.AddError(r.gatherCommandValues(client, acc))
 		}(client)
 	}
 
 	wg.Wait()
 	return nil
 }
 
+func (r *Redis) gatherCommandValues(client Client, acc telegraf.Accumulator) error {
+	fields := make(map[string]interface{})
+	for _, command := range r.Commands {
+		val, err := client.Do(command.Type, command.Command...)
+		if err != nil {
+			return err
+		}
+
+		fields[command.Field] = val
+	}
+
+	acc.AddFields("redis_commands", fields, client.BaseTags())
+
+	return nil
+}
+
 func (r *Redis) gatherServer(client Client, acc telegraf.Accumulator) error {
 	info, err := client.Info().Result()
 	if err != nil {

plugins/inputs/redis/redis_test.go

@@ -7,11 +7,27 @@ import (
 	"testing"
 	"time"
 
+	"github.com/go-redis/redis"
 	"github.com/influxdata/telegraf/testutil"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
+type testClient struct {
+}
+
+func (t *testClient) BaseTags() map[string]string {
+	return map[string]string{"host": "redis.net"}
+}
+
+func (t *testClient) Info() *redis.StringCmd {
+	return nil
+}
+
+func (t *testClient) Do(returnType string, args ...interface{}) (interface{}, error) {
+	return 2, nil
+}
+
 func TestRedisConnect(t *testing.T) {
 	if testing.Short() {
 		t.Skip("Skipping integration test in short mode")
@@ -30,6 +46,33 @@ func TestRedisConnect(t *testing.T) {
 	require.NoError(t, err)
 }
 
+func TestRedis_Commands(t *testing.T) {
+	const redisListKey = "test-list-length"
+	var acc testutil.Accumulator
+
+	tc := &testClient{}
+
+	rc := &RedisCommand{
+		Command: []interface{}{"llen", "test-list"},
+		Field:   redisListKey,
+		Type:    "integer",
+	}
+
+	r := &Redis{
+		Commands: []*RedisCommand{rc},
+		clients:  []Client{tc},
+	}
+
+	err := r.gatherCommandValues(tc, &acc)
+	require.NoError(t, err)
+
+	fields := map[string]interface{}{
+		redisListKey: 2,
+	}
+
+	acc.AssertContainsFields(t, "redis_commands", fields)
+}
+
 func TestRedis_ParseMetrics(t *testing.T) {
 	var acc testutil.Accumulator
 	tags := map[string]string{"host": "redis.net"}