[connector/metricsaslogsconnector] first version of metricsaslogs connector

.chloggen/metricsaslogsconnector.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: new_component
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: metricsaslogsconnector
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add connector to convert metrics to logs
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [40938]
+
+# (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]

.github/CODEOWNERS

@@ -33,6 +33,7 @@ connector/datadogconnector/                                      @open-telemetry
 connector/exceptionsconnector/                                   @open-telemetry/collector-contrib-approvers @marctc
 connector/failoverconnector/                                     @open-telemetry/collector-contrib-approvers @akats7 @fatsheep9146
 connector/grafanacloudconnector/                                 @open-telemetry/collector-contrib-approvers @rlankfo @jcreixell
+connector/metricsaslogsconnector/                                @open-telemetry/collector-contrib-approvers @atoulme
 connector/otlpjsonconnector/                                     @open-telemetry/collector-contrib-approvers @ChrsMark
 connector/roundrobinconnector/                                   @open-telemetry/collector-contrib-approvers @bogdandrutu
 connector/routingconnector/                                      @open-telemetry/collector-contrib-approvers @mwear @TylerHelmuth @evan-bradley @edmocosta

.github/ISSUE_TEMPLATE/beta_stability.yaml

@@ -30,6 +30,7 @@ body:
       - connector/exceptions
       - connector/failover
       - connector/grafanacloud
+      - connector/metricsaslogs
       - connector/otlpjson
       - connector/roundrobin
       - connector/routing

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -33,6 +33,7 @@ body:
       - connector/exceptions
       - connector/failover
       - connector/grafanacloud
+      - connector/metricsaslogs
       - connector/otlpjson
       - connector/roundrobin
       - connector/routing

.github/ISSUE_TEMPLATE/feature_request.yaml

@@ -27,6 +27,7 @@ body:
       - connector/exceptions
       - connector/failover
       - connector/grafanacloud
+      - connector/metricsaslogs
       - connector/otlpjson
       - connector/roundrobin
       - connector/routing

.github/ISSUE_TEMPLATE/other.yaml

@@ -27,6 +27,7 @@ body:
       - connector/exceptions
       - connector/failover
       - connector/grafanacloud
+      - connector/metricsaslogs
       - connector/otlpjson
       - connector/roundrobin
       - connector/routing

.github/ISSUE_TEMPLATE/unmaintained.yaml

@@ -32,6 +32,7 @@ body:
       - connector/exceptions
       - connector/failover
       - connector/grafanacloud
+      - connector/metricsaslogs
       - connector/otlpjson
       - connector/roundrobin
       - connector/routing

.github/component_labels.txt

@@ -14,6 +14,7 @@ connector/datadogconnector connector/datadog
 connector/exceptionsconnector connector/exceptions
 connector/failoverconnector connector/failover
 connector/grafanacloudconnector connector/grafanacloud
+connector/metricsaslogsconnector connector/metricsaslogs
 connector/otlpjsonconnector connector/otlpjson
 connector/roundrobinconnector connector/roundrobin
 connector/routingconnector connector/routing

connector/metricsaslogsconnector/Makefile

@@ -0,0 +1 @@
+include ../../Makefile.Common

connector/metricsaslogsconnector/README.md

@@ -0,0 +1,150 @@
+# metricsaslogsconnector
+
+<!-- status autogenerated section -->
+| Status        |           |
+| ------------- |-----------|
+| Distributions | [] |
+| Issues        | [![Open issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aopen%20label%3Aconnector%2Fmetricsaslogs%20&label=open&color=orange&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aopen+is%3Aissue+label%3Aconnector%2Fmetricsaslogs) [![Closed issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aclosed%20label%3Aconnector%2Fmetricsaslogs%20&label=closed&color=blue&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aclosed+is%3Aissue+label%3Aconnector%2Fmetricsaslogs) |
+| Code coverage | [![codecov](https://codecov.io/github/open-telemetry/opentelemetry-collector-contrib/graph/main/badge.svg?component=connector_metricsaslogs)](https://app.codecov.io/gh/open-telemetry/opentelemetry-collector-contrib/tree/main/?components%5B0%5D=connector_metricsaslogs&displayType=list) |
+| [Code Owners](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/CONTRIBUTING.md#becoming-a-code-owner)    | [@atoulme](https://www.github.com/atoulme) |
+
+[development]: https://github.com/open-telemetry/opentelemetry-collector/blob/main/docs/component-stability.md#development
+
+## Supported Pipeline Types
+
+| [Exporter Pipeline Type] | [Receiver Pipeline Type] | [Stability Level] |
+| ------------------------ | ------------------------ | ----------------- |
+| metrics | logs | [development] |
+
+[Exporter Pipeline Type]: https://github.com/open-telemetry/opentelemetry-collector/blob/main/connector/README.md#exporter-pipeline-type
+[Receiver Pipeline Type]: https://github.com/open-telemetry/opentelemetry-collector/blob/main/connector/README.md#receiver-pipeline-type
+[Stability Level]: https://github.com/open-telemetry/opentelemetry-collector/blob/main/docs/component-stability.md#stability-levels
+<!-- end autogenerated section -->
+
+This connector converts OpenTelemetry metrics into logs, creating one log entry per metric data point. Each metric data point is transformed into a structured log record with configurable JSON body format.
+
+## Current Limitations
+
+⚠️ **Current implementation discards the following metric features:**
+- Metric exemplars
+- Advanced metadata
+
+These features may be added in future iterations.
+
+## Configuration
+
+The following settings can be optionally configured:
+
+- `include_resource_attributes` (default = `true`): Whether to include resource attributes in the generated logs
+- `include_scope_info` (default = `true`): Whether to include instrumentation scope information in the generated logs
+
+## Log Body Format
+
+The connector always generates log bodies in the following JSON format:
+```json
+{"metric_name": "$NAME", "value": "$VALUE"}
+```
+
+Where:
+- `$NAME` is the actual metric name
+- `$VALUE` is the metric value (simple values for gauge/sum, complex JSON for histogram/summary)
+
+## Example Usage
+
+### Basic Configuration
+
+```yaml
+connectors:
+  metricsaslogs:
+
+service:
+  pipelines:
+    logs:
+      receivers: [metricsaslogs]
+      processors: []
+      exporters: [logging]
+    metrics:
+      receivers: [otlp]
+      processors: []
+      exporters: [metricsaslogs]
+```
+
+### Advanced Configuration
+
+```yaml
+connectors:
+  metricsaslogs:
+    include_resource_attributes: false
+    include_scope_info: false
+```
+
+
+### Example Metric Conversions
+
+For a gauge metric `cpu_usage` with value `85.2`:
+```json
+{
+  "body": {"metric_name": "cpu_usage", "value": "85.2"},
+  "attributes": {
+    "metric.name": "cpu_usage",
+    "metric.type": "Gauge",
+    "metric.description": "CPU usage percentage",
+    "metric.unit": "%"
+  }
+}
+```
+
+For a histogram metric `request_duration`:
+```json
+{
+  "body": {
+    "metric_name": "request_duration", 
+    "value": "{\"count\":100,\"sum\":1.5,\"bucket_counts\":[10,50,40],\"explicit_bounds\":[0.1,0.5,1.0]}"
+  },
+  "attributes": {
+    "metric.name": "request_duration",
+    "metric.type": "Histogram",
+    "metric.description": "Request duration in seconds",
+    "metric.unit": "s",
+    "metric.aggregation_temporality": "Delta"
+  }
+}
+```
+
+## Output Structure
+
+Each metric data point is converted to a log record with:
+
+- **Body**: Fixed JSON format: `{"metric_name": "$NAME", "value": "$VALUE"}`
+- **Timestamp**: Metric data point timestamp
+- **Observed Timestamp**: Metric data point start timestamp (if available)
+- **Attributes**: 
+  - Original metric data point attributes (labels)
+  - `metric.name`: The metric name
+  - `metric.type`: The metric type (Gauge, Sum, Histogram, etc.)
+  - `metric.description`: Metric description (if available)
+  - `metric.unit`: Metric unit (if available)
+  - Additional type-specific attributes:
+    - For Sum metrics: `metric.is_monotonic`, `metric.aggregation_temporality`
+    - For Histogram/ExponentialHistogram: `metric.aggregation_temporality`
+  - Resource attributes (if `include_resource_attributes` is true)
+  - Instrumentation scope information (if `include_scope_info` is true)
+
+## Supported Metric Types
+
+All OpenTelemetry metric types are supported:
+
+- **Gauge**: Point-in-time measurements
+- **Sum**: Cumulative or delta measurements  
+- **Histogram**: Distribution of measurements with buckets
+- **Exponential Histogram**: Distribution with exponentially sized buckets
+- **Summary**: Distribution with quantile values
+
+## Value Encoding
+
+The `value` field in the JSON body contains:
+
+- For simple metrics (Gauge, Sum): numeric value as string
+- For complex metrics (Histogram, etc.): JSON-encoded object as string
+
+All JSON special characters in metric names and values are properly escaped.

connector/metricsaslogsconnector/config.go

@@ -0,0 +1,27 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package metricsaslogsconnector // import "github.com/open-telemetry/opentelemetry-collector-contrib/connector/metricsaslogsconnector"
+
+import (
+	"go.opentelemetry.io/collector/component"
+)
+
+type Config struct {
+	IncludeResourceAttributes bool `mapstructure:"include_resource_attributes"`
+
+	IncludeScopeInfo bool `mapstructure:"include_scope_info"`
+
+	_ struct{}
+}
+
+func (*Config) Validate() error {
+	return nil
+}
+
+func createDefaultConfig() component.Config {
+	return &Config{
+		IncludeResourceAttributes: true,
+		IncludeScopeInfo:          true,
+	}
+}