pyroscope: Add relabel component for modifying and filtering profiles

CHANGELOG.md

@@ -14,6 +14,8 @@ Main (unreleased)
 
 - Add the possibility to export span events as logs in `otelcol.connector.spanlogs`. (@steve-hb)
 
+- Add `pyroscope.relabel` component to modify or filter profiles using Prometheus relabeling rules. (@marcsanmi)
+
 ### Enhancements
 
 - (_Experimental_) Log instance label key in `database_observability.mysql` (@cristiangreco)

docs/sources/reference/compatibility/_index.md

@@ -393,6 +393,7 @@ The following components, grouped by namespace, _export_ Pyroscope `ProfilesRece
 
 {{< collapse title="pyroscope" >}}
 - [pyroscope.write](../components/pyroscope/pyroscope.write)
+- [pyroscope.relabel](../components/pyroscope/pyroscope.relabel)
 {{< /collapse >}}
 
 <!-- END GENERATED SECTION: EXPORTERS OF Pyroscope `ProfilesReceiver` -->
@@ -409,6 +410,7 @@ The following components, grouped by namespace, _consume_ Pyroscope `ProfilesRec
 - [pyroscope.java](../components/pyroscope/pyroscope.java)
 - [pyroscope.receive_http](../components/pyroscope/pyroscope.receive_http)
 - [pyroscope.scrape](../components/pyroscope/pyroscope.scrape)
+- [pyroscope.relabel](../components/pyroscope/pyroscope.relabel)
 {{< /collapse >}}
 
 <!-- END GENERATED SECTION: CONSUMERS OF Pyroscope `ProfilesReceiver` -->

docs/sources/reference/components/pyroscope/pyroscope.relabel.md

@@ -0,0 +1,114 @@
+---
+canonical: https://grafana.com/docs/alloy/latest/reference/components/pyroscope/pyroscope.relabel/
+aliases:
+  - ../pyroscope.relabel/ # /docs/alloy/latest/reference/components/pyroscope.relabel/
+description: Learn about pyroscope.relabel
+title: pyroscope.relabel
+---
+
+# pyroscope.relabel
+
+The `pyroscope.relabel` component rewrites the label set of each profile passed to its receiver by applying one or more relabeling `rule`s and forwards the results to the list of receivers in the component's arguments.
+
+If no rules are defined or applicable to some profiles, then those profiles are forwarded as-is to each receiver passed in the component's arguments. If no labels remain after the relabeling rules are applied, then the profile is dropped.
+
+The most common use of `pyroscope.relabel` is to filter profiles or standardize the label set that is passed to one or more downstream receivers. The `rule` blocks are applied to the label set of each profile in order of their appearance in the configuration file.
+
+## Usage
+
+```alloy
+pyroscope.relabel "process" {
+    forward_to = RECEIVER_LIST
+
+    rule {
+        ...
+    }
+
+    ...
+}
+```
+
+## Arguments
+
+The following arguments are supported:
+
+| Name | Type | Description | Default | Required |
+| ---- | ---- | ----------- | ------- | -------- |
+| `forward_to` | `list(pyroscope.Appendable)` | List of receivers to forward profiles to after relabeling | | yes |
+| `max_cache_size` | `number` | Maximum number of entries in the label cache | 10000 | no |
+
+## Blocks
+
+The following blocks are supported inside the definition of `pyroscope.relabel`:
+
+Hierarchy | Name     | Description                                        | Required
+----------|----------|----------------------------------------------------|---------
+rule      | [rule][] | Relabeling rules to apply to received log entries. | no
+
+[rule]: #rule-block
+
+### rule block
+
+{{< docs/shared lookup="reference/components/rule-block-logs.md" source="alloy" version="<ALLOY_VERSION>" >}}
+
+## Exported fields
+
+The following fields are exported and can be referenced by other components:
+
+Name | Type | Description
+-----|------|------------
+`receiver` | `ProfilesReceiver` | A receiver that accepts profiles for relabeling.
+`rules` | `[]relabel.Config` | The list of relabeling rules.
+
+## Component health
+
+`pyroscope.relabel` is reported as unhealthy if it is given an invalid configuration.
+
+## Debug metrics
+
+* `pyroscope_relabel_profiles_dropped` (counter): Total number of profiles dropped by relabeling rules.
+* `pyroscope_relabel_profiles_processed` (counter): Total number of profiles processed.
+* `pyroscope_relabel_profiles_written` (counter): Total number of profiles forwarded.
+* `pyroscope_relabel_cache_misses` (counter): Total number of cache misses.
+* `pyroscope_relabel_cache_hits` (counter): Total number of cache hits.
+* `pyroscope_relabel_cache_size` (gauge): Total size of relabel cache.
+
+## Example
+
+```alloy
+pyroscope.relabel "process" {
+    forward_to = [pyroscope.write.backend.receiver]
+
+    # Rules are applied in order
+    rule {
+        source_labels = ["env"]
+        target_label = "environment"
+        action = "replace"
+        regex = "(.)"
+        replacement = "$1"
+    }
+
+    rule {
+        action = "labeldrop"
+        regex = "env"
+    }
+}
+```
+
+<!-- START GENERATED COMPATIBLE COMPONENTS -->
+## Compatible components
+
+`pyroscope.relabel` can accept arguments from the following components:
+
+- Components that export [Pyroscope `ProfilesReceiver`](../../../compatibility/#pyroscope-profilesreceiver-exporters)
+
+`pyroscope.relabel` has exports that can be consumed by the following components:
+
+- Components that consume [Pyroscope `ProfilesReceiver`](../../../compatibility/#pyroscope-profilesreceiver-consumers)
+
+{{< admonition type="note" >}}
+Connecting some components may not be sensible or components may require further configuration to make the connection work correctly.
+Refer to the linked documentation for more details.
+{{< /admonition >}}
+
+<!-- END GENERATED COMPATIBLE COMPONENTS -->

internal/component/all/all.go

@@ -146,6 +146,7 @@ import (
 	_ "github.com/grafana/alloy/internal/component/pyroscope/ebpf"                           // Import pyroscope.ebpf
 	_ "github.com/grafana/alloy/internal/component/pyroscope/java"                           // Import pyroscope.java
 	_ "github.com/grafana/alloy/internal/component/pyroscope/receive_http"                   // Import pyroscope.receive_http
+	_ "github.com/grafana/alloy/internal/component/pyroscope/relabel"                        // Import pyroscope.relabel
 	_ "github.com/grafana/alloy/internal/component/pyroscope/scrape"                         // Import pyroscope.scrape
 	_ "github.com/grafana/alloy/internal/component/pyroscope/write"                          // Import pyroscope.write
 	_ "github.com/grafana/alloy/internal/component/remote/http"                              // Import remote.http

internal/component/pyroscope/relabel/metrics.go

@@ -0,0 +1,52 @@
+package relabel
+
+import "github.com/prometheus/client_golang/prometheus"
+
+type metrics struct {
+	profilesProcessed prometheus.Counter
+	profilesOutgoing  prometheus.Counter
+	profilesDropped   prometheus.Counter
+	cacheHits         prometheus.Counter
+	cacheMisses       prometheus.Counter
+	cacheSize         prometheus.Gauge
+}
+
+func newMetrics(reg prometheus.Registerer) *metrics {
+	m := &metrics{
+		profilesProcessed: prometheus.NewCounter(prometheus.CounterOpts{
+			Name: "pyroscope_relabel_profiles_processed",
+			Help: "Total number of profiles processed",
+		}),
+		profilesOutgoing: prometheus.NewCounter(prometheus.CounterOpts{
+			Name: "pyroscope_relabel_profiles_written",
+			Help: "Total number of profiles forwarded",
+		}),
+		profilesDropped: prometheus.NewCounter(prometheus.CounterOpts{
+			Name: "pyroscope_relabel_profiles_dropped",
+			Help: "Total number of profiles dropped by relabeling rules",
+		}),
+		cacheHits: prometheus.NewCounter(prometheus.CounterOpts{
+			Name: "pyroscope_relabel_cache_hits",
+			Help: "Total number of cache hits",
+		}),
+		cacheMisses: prometheus.NewCounter(prometheus.CounterOpts{
+			Name: "pyroscope_relabel_cache_misses",
+			Help: "Total number of cache misses",
+		}),
+		cacheSize: prometheus.NewGauge(prometheus.GaugeOpts{
+			Name: "pyroscope_relabel_cache_size",
+			Help: "Total size of relabel cache",
+		}),
+	}
+
+	reg.MustRegister(
+		m.profilesProcessed,
+		m.profilesOutgoing,
+		m.profilesDropped,
+		m.cacheHits,
+		m.cacheMisses,
+		m.cacheSize,
+	)
+
+	return m
+}