[receiver/redisreceiver] Add support for Redis sentinel information (#42401)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description

Add support for exposing Redis sentinel and mode metrics.

Redis Sentinel metrics with Redis mode:

```sh
# HELP redis_mode Redis server mode
# TYPE redis_mode gauge
redis_mode{mode="sentinel",otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 1
# HELP redis_sentinel_masters Number of masters monitored by Sentinel.
# TYPE redis_sentinel_masters gauge
redis_sentinel_masters{otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 1
# HELP redis_sentinel_running_scripts Number of running Sentinel scripts.
# TYPE redis_sentinel_running_scripts gauge
redis_sentinel_running_scripts{otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 0
# HELP redis_sentinel_scripts_queue_length Length of Sentinel scripts queue.
# TYPE redis_sentinel_scripts_queue_length gauge
redis_sentinel_scripts_queue_length{otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 0
# HELP redis_sentinel_simulate_failure_flags Simulated failure flags bitmask.
# TYPE redis_sentinel_simulate_failure_flags gauge
redis_sentinel_simulate_failure_flags{otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 0
# HELP redis_sentinel_tilt Whether Sentinel is in TILT mode (1 = tilt, 0 = normal).
# TYPE redis_sentinel_tilt gauge
redis_sentinel_tilt{otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 0
# HELP redis_sentinel_tilt_since_seconds Duration in seconds of current TILT, or -1 if not in TILT mode.
# TYPE redis_sentinel_tilt_since_seconds gauge
redis_sentinel_tilt_since_seconds{otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} -1
# HELP redis_sentinel_tilt_total Total TILT occurrences since start.
# TYPE redis_sentinel_tilt_total counter
redis_sentinel_tilt_total{otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 0
```

Redis mode (standalone):

```sh
# HELP redis_mode Redis server mode
# TYPE redis_mode gauge
redis_mode{mode="standalone",otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 1
```

Redis mode (cluster):

```sh
# HELP redis_mode Redis server mode
# TYPE redis_mode gauge
redis_mode{mode="cluster",otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 1
```

<!-- Issue number (e.g. #1234) or full URL to issue, if applicable. -->
#### Link to tracking issue
Fixes #42365 

<!--Describe what testing was performed and which tests were added.-->
#### Testing

I tested this against all the possible modes (sentinel, standalone, and
cluster). The sentinel metrics are only evaluated and exposed when
`redis_mode:sentinel`.

I also added integration tests `TestIntegrationV8Sentinel` for the
`sentinel` mode.

<!--Describe the documentation added.-->
#### Documentation

Updated the documentation using `mdatagen`

<!--Please delete paragraphs that you did not use before submitting.-->

---------

Signed-off-by: Paulo Dias <[email protected]>

Author: paulojmdias

.chloggen/feat_42365.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: "enhancement"
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: "receiver/redis"
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: "Add support for redis.mode and redis.sentinel.* metrics"
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [42365]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

receiver/redisreceiver/documentation.md

@@ -455,6 +455,20 @@ Initial amount of memory consumed by Redis at startup in bytes
 | ---- | ----------- | ---------- | ----------------------- | --------- | --------- |
 | By | Sum | Int | Cumulative | false | Development |
 
+### redis.mode
+
+Redis server mode
+
+| Unit | Metric Type | Value Type | Stability |
+| ---- | ----------- | ---------- | --------- |
+| {mode} | Gauge | Int | Development |
+
+#### Attributes
+
+| Name | Description | Values | Requirement Level |
+| ---- | ----------- | ------ | -------- |
+| mode | Redis server mode | Str: ``cluster``, ``sentinel``, ``standalone`` | Recommended |
+
 ### redis.replication.replica_offset
 
 Offset for redis replica
@@ -477,6 +491,54 @@ Redis node's role
 | ---- | ----------- | ------ | -------- |
 | role | Redis node's role | Str: ``replica``, ``primary`` | Recommended |
 
+### redis.sentinel.masters
+
+Number of masters monitored by Sentinel.
+
+| Unit | Metric Type | Value Type | Stability |
+| ---- | ----------- | ---------- | --------- |
+| {master} | Gauge | Int | Development |
+
+### redis.sentinel.running_scripts
+
+Number of running Sentinel scripts.
+
+| Unit | Metric Type | Value Type | Stability |
+| ---- | ----------- | ---------- | --------- |
+| {script} | Gauge | Int | Development |
+
+### redis.sentinel.scripts_queue_length
+
+Length of Sentinel scripts queue.
+
+| Unit | Metric Type | Value Type | Stability |
+| ---- | ----------- | ---------- | --------- |
+| {script} | Gauge | Int | Development |
+
+### redis.sentinel.simulate_failure_flags
+
+Simulated failure flags bitmask.
+
+| Unit | Metric Type | Value Type | Stability |
+| ---- | ----------- | ---------- | --------- |
+| {flag} | Gauge | Int | Development |
+
+### redis.sentinel.tilt_since_seconds
+
+Duration in seconds of current TILT, or -1 if not in TILT mode.
+
+| Unit | Metric Type | Value Type | Stability |
+| ---- | ----------- | ---------- | --------- |
+| s | Gauge | Int | Development |
+
+### redis.sentinel.total_tilt
+
+Total TILT occurrences since start.
+
+| Unit | Metric Type | Value Type | Aggregation Temporality | Monotonic | Stability |
+| ---- | ----------- | ---------- | ----------------------- | --------- | --------- |
+| {event} | Sum | Int | Cumulative | true | Development |
+
 ### redis.tracking_total_keys
 
 Number of keys being tracked by the server

receiver/redisreceiver/integration_test.go

@@ -19,7 +19,10 @@ import (
 	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/pdatatest/pmetrictest"
 )
 
-const redisPort = "6379"
+const (
+	redisPort    = "6379"
+	sentinelPort = "26379"
+)
 
 func TestIntegrationV6(t *testing.T) {
 	scraperinttest.NewIntegrationTest(
@@ -38,6 +41,8 @@ func TestIntegrationV6(t *testing.T) {
 		scraperinttest.WithCompareOptions(
 			pmetrictest.IgnoreMetricValues(),
 			pmetrictest.IgnoreMetricDataPointsOrder(),
+			pmetrictest.IgnoreMetricsOrder(),
+			pmetrictest.IgnoreResourceMetricsOrder(),
 			pmetrictest.IgnoreStartTimestamp(),
 			pmetrictest.IgnoreTimestamp(),
 			pmetrictest.ChangeResourceAttributeValue("server.address", func(_ string) string {
@@ -83,6 +88,8 @@ func TestIntegrationV7Cluster(t *testing.T) {
 		scraperinttest.WithCompareOptions(
 			pmetrictest.IgnoreMetricValues(),
 			pmetrictest.IgnoreMetricDataPointsOrder(),
+			pmetrictest.IgnoreMetricsOrder(),
+			pmetrictest.IgnoreResourceMetricsOrder(),
 			pmetrictest.IgnoreStartTimestamp(),
 			pmetrictest.IgnoreTimestamp(),
 		),
@@ -91,3 +98,48 @@ func TestIntegrationV7Cluster(t *testing.T) {
 		scraperinttest.WithCompareTimeout(time.Minute),
 	).Run(t)
 }
+
+func TestIntegrationV8Sentinel(t *testing.T) {
+	scraperinttest.NewIntegrationTest(
+		NewFactory(),
+		scraperinttest.WithContainerRequest(
+			testcontainers.ContainerRequest{
+				Image:        "redis:8.2.1",
+				ExposedPorts: []string{sentinelPort},
+				Cmd: []string{
+					"redis-sentinel",
+					"/etc/redis/sentinel.conf",
+				},
+				Files: []testcontainers.ContainerFile{
+					{
+						HostFilePath:      filepath.Join("testdata", "integration", "redis-sentinel.conf"),
+						ContainerFilePath: "/etc/redis/sentinel.conf",
+						FileMode:          0o644,
+					},
+				},
+				WaitingFor: wait.ForListeningPort(sentinelPort),
+			}),
+		scraperinttest.WithCustomConfig(
+			func(t *testing.T, cfg component.Config, ci *scraperinttest.ContainerInfo) {
+				rCfg := cfg.(*Config)
+				rCfg.Endpoint = fmt.Sprintf("%s:%s", ci.Host(t), ci.MappedPort(t, sentinelPort))
+				rCfg.MetricsBuilderConfig.Metrics.RedisMode.Enabled = true
+				rCfg.MetricsBuilderConfig.Metrics.RedisSentinelMasters.Enabled = true
+				rCfg.MetricsBuilderConfig.Metrics.RedisSentinelRunningScripts.Enabled = true
+				rCfg.MetricsBuilderConfig.Metrics.RedisSentinelScriptsQueueLength.Enabled = true
+				rCfg.MetricsBuilderConfig.Metrics.RedisSentinelSimulateFailureFlags.Enabled = true
+				rCfg.MetricsBuilderConfig.Metrics.RedisSentinelTiltSinceSeconds.Enabled = true
+				rCfg.MetricsBuilderConfig.Metrics.RedisSentinelTotalTilt.Enabled = true
+			}),
+		scraperinttest.WithCompareOptions(
+			pmetrictest.IgnoreMetricValues(),
+			pmetrictest.IgnoreMetricDataPointsOrder(),
+			pmetrictest.IgnoreMetricsOrder(),
+			pmetrictest.IgnoreResourceMetricsOrder(),
+			pmetrictest.IgnoreStartTimestamp(),
+			pmetrictest.IgnoreTimestamp(),
+		),
+		scraperinttest.WithExpectedFile(filepath.Join("testdata", "integration", "expected-sentinel.yaml")),
+		scraperinttest.WithCreateContainerTimeout(time.Minute),
+	).Run(t)
+}