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otelcol.processor.groupbyattrs

otelcol.processor.groupbyattrs accepts spans, metrics, and traces from other otelcol components and groups them under the same resource.

Note

otelcol.processor.groupbyattrs is a wrapper over the upstream OpenTelemetry Collector groupbyattrs processor. If necessary, bug reports or feature requests will be redirected to the upstream repository.

We recommend you use the groupbyattrs processor together with otelcol.processor.batch, as a consecutive step. This will reduce the fragmentation of data by grouping records together under the matching Resource/Instrumentation Library.

You can specify multiple otelcol.processor.groupbyattrs components by giving them different labels.

Usage

alloy
otelcol.processor.groupbyattrs "LABEL" {
  output {
    metrics = [...]
    logs    = [...]
    traces  = [...]
  }
}

Arguments

The following arguments are supported:

NameTypeDescriptionDefaultRequired
keyslist(string)Keys that will be used to group the spans, log records, or metric data points together.[]no

keys is a string array that is used for grouping the data. If it is empty, the processor performs compaction and reassociates all spans with matching Resource and InstrumentationLibrary.

Blocks

The following blocks are supported inside the definition of otelcol.processor.groupbyattrs:

HierarchyBlockDescriptionRequired
outputoutputConfigures where to send received telemetry data.yes
debug_metricsdebug_metricsConfigures the metrics that this component generates to monitor its state.no

output block

The output block configures a set of components to forward resulting telemetry data to.

The following arguments are supported:

NameTypeDescriptionDefaultRequired
logslist(otelcol.Consumer)List of consumers to send logs to.[]no
metricslist(otelcol.Consumer)List of consumers to send metrics to.[]no
traceslist(otelcol.Consumer)List of consumers to send traces to.[]no

You must specify the output block, but all its arguments are optional. By default, telemetry data is dropped. Configure the metrics, logs, and traces arguments accordingly to send telemetry data to other components.

debug_metrics block

The debug_metrics block configures the metrics that this component generates to monitor its state.

The following arguments are supported:

NameTypeDescriptionDefaultRequired
disable_high_cardinality_metricsbooleanWhether to disable certain high cardinality metrics.trueno
levelstringControls the level of detail for metrics emitted by the wrapped collector."detailed"no

disable_high_cardinality_metrics is the Grafana Alloy equivalent to the telemetry.disableHighCardinalityMetrics feature gate in the OpenTelemetry Collector. It removes attributes that could cause high cardinality metrics. For example, attributes with IP addresses and port numbers in metrics about HTTP and gRPC connections are removed.

Note

If configured, disable_high_cardinality_metrics only applies to otelcol.exporter.* and otelcol.receiver.* components.

level is the Alloy equivalent to the telemetry.metrics.level feature gate in the OpenTelemetry Collector. Possible values are "none", "basic", "normal" and "detailed".

Exported fields

The following fields are exported and can be referenced by other components:

NameTypeDescription
inputotelcol.ConsumerAccepts otelcol.Consumer data for metrics, logs, or traces.

input accepts otelcol.Consumer data for any telemetry signal (metrics, logs, or traces).

Component health

otelcol.processor.groupbyattrs is only reported as unhealthy if given an invalid configuration.

Debug information

otelcol.processor.groupbyattrs doesn’t expose any component-specific debug information.

Debug metrics

otelcol.processor.groupbyattrs doesn’t expose any component-specific debug metrics.

Examples

Grouping metrics

Consider the following metrics, all originally associated to the same Resource:

Resource {host.name="localhost",source="prom"}
  Metric "gauge-1" (GAUGE)
    DataPoint {host.name="host-A",id="eth0"}
    DataPoint {host.name="host-A",id="eth0"}
    DataPoint {host.name="host-B",id="eth0"}
  Metric "gauge-1" (GAUGE) // Identical to previous Metric
    DataPoint {host.name="host-A",id="eth0"}
    DataPoint {host.name="host-A",id="eth0"}
    DataPoint {host.name="host-B",id="eth0"}
  Metric "mixed-type" (GAUGE)
    DataPoint {host.name="host-A",id="eth0"}
    DataPoint {host.name="host-A",id="eth0"}
    DataPoint {host.name="host-B",id="eth0"}
  Metric "mixed-type" (SUM)
    DataPoint {host.name="host-A",id="eth0"}
    DataPoint {host.name="host-A",id="eth0"}
  Metric "dont-move" (Gauge)
    DataPoint {id="eth0"}

With the following configuration, the groupbyattrs will re-associate the metrics with either host-A or host-B, based on the value of the host.name attribute.

alloy
otelcol.processor.groupbyattrs "default" {
  keys = [ "host.name" ]
  output {
    metrics = [otelcol.exporter.otlp.default.input]
  }
}

The output of the processor will therefore be:

Resource {host.name="localhost",source="prom"}
  Metric "dont-move" (Gauge)
    DataPoint {id="eth0"}
Resource {host.name="host-A",source="prom"}
  Metric "gauge-1"
    DataPoint {id="eth0"}
    DataPoint {id="eth0"}
    DataPoint {id="eth0"}
    DataPoint {id="eth0"}
  Metric "mixed-type" (GAUGE)
    DataPoint {id="eth0"}
    DataPoint {id="eth0"}
  Metric "mixed-type" (SUM)
    DataPoint {id="eth0"}
    DataPoint {id="eth0"}
Resource {host.name="host-B",source="prom"}
  Metric "gauge-1"
    DataPoint {id="eth0"}
    DataPoint {id="eth0"}
  Metric "mixed-type" (GAUGE)
    DataPoint {id="eth0"}

This output demonstrates how otelcol.processor.groupbyattrs works in various situations:

  • The DataPoints for the gauge-1 (GAUGE) metric were originally split under 2 Metric instances and have been merged in the output.
  • The DataPoints of the mixed-type (GAUGE) and mixed-type (SUM) metrics have not been merged under the same Metric, because their DataType is different.
  • The dont-move metric DataPoints don’t have a host.name attribute and therefore remained under the original Resource.
  • The new Resources inherited the attributes from the original Resource (source="prom"), plus the specified attributes from the processed metrics (host.name="host-A" or host.name="host-B").
  • The specified “grouping” attributes that are set on the new Resources are also removed from the metric DataPoints.
  • While not shown in the above example, the processor also merges collections of records under matching InstrumentationLibrary.

Compaction

Sometimes telemetry data can become fragmented due to multiple duplicated ResourceSpans/ResourceLogs/ResourceMetrics objects. This leads to additional memory consumption, increased processing costs, inefficient serialization and increase of the export requests. In such situations, otelcol.processor.groupbyattrs can be used to compact the data with matching Resource and InstrumentationLibrary properties.

For example, consider this input data:

Resource {host.name="localhost"}
  InstrumentationLibrary {name="MyLibrary"}
  Spans
    Span {span_id=1, ...}
  InstrumentationLibrary {name="OtherLibrary"}
  Spans
    Span {span_id=2, ...}
    
Resource {host.name="localhost"}
  InstrumentationLibrary {name="MyLibrary"}
  Spans
    Span {span_id=3, ...}
    
Resource {host.name="localhost"}
  InstrumentationLibrary {name="MyLibrary"}
  Spans
    Span {span_id=4, ...}
    
Resource {host.name="otherhost"}
  InstrumentationLibrary {name="MyLibrary"}
  Spans
    Span {span_id=5, ...}

You can use otelcol.processor.groupbyattrs with its default configuration to compact the data:

alloy
otelcol.processor.groupbyattrs "default" {
  output {
    metrics = [otelcol.exporter.otlp.default.input]
  }
}

The output will be:

Resource {host.name="localhost"}
  InstrumentationLibrary {name="MyLibrary"}
  Spans
    Span {span_id=1, ...}
    Span {span_id=3, ...}
    Span {span_id=4, ...}
  InstrumentationLibrary {name="OtherLibrary"}
  Spans
    Span {span_id=2, ...}

Resource {host.name="otherhost"}
  InstrumentationLibrary {name="MyLibrary"}
  Spans
    Span {span_id=5, ...}

Compatible components

otelcol.processor.groupbyattrs can accept arguments from the following components:

otelcol.processor.groupbyattrs has exports that can be consumed by the following components:

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.