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Metricsaslogs Connector

Status Maintainers: @atoulme Source: opentelemetry-collector-contrib

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Overview

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.

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Current Limitations

⚠️ Current implementation discards the following metric features:
  • Metric exemplars
  • Advanced metadata
These features may be added in future iterations.

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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

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Log Body Format

The connector always generates log bodies in the following JSON format: 
{"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)

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Example Usage

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Basic Configuration

connectors:
  metricsaslogs:

service:
  pipelines:
    logs:
      receivers: [metricsaslogs]
      processors: []
      exporters: [debug]
    metrics:
      receivers: [otlp]
      processors: []
      exporters: [metricsaslogs]

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Advanced Configuration

connectors:
  metricsaslogs:
    include_resource_attributes: false
    include_scope_info: false

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Example Metric Conversions

For a gauge metric cpu_usage with value 85.2: 
{
  "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: 
{
  "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"
  }
}

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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)

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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

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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.
Last generated: 2026-04-13