Metricize filter plugin

Splits a complex event that contains several metrics into one smaller event per metric. Useful when downstream tooling indexes one metric per document.

• Package: logstash-filter-metricize
• Coverage source: default/bundled, explicitly installed in the Logit image
• Official catalog entry: Yes

Plugin overview

metricize is used in the Logstash filter stage. Splits complex events into per-metric events.

Typical use cases

• Transform fields before indexing to keep schema and naming consistent.
• Prepare high-quality fields for alerts, dashboards, and downstream pipelines.

Input and output behavior

• Flow: processes matching events and mutates fields/tags within the same event.
• Input: works on events that match your surrounding if conditions.
• Output: updates the current event in place unless configured otherwise.
• Important options: metrics, drop_original_event, metric_field_name, value_field_name.

Options

Required

• metrics (type: array; default: none) — List of field names in the source event that each represent a metric.

Optional

• drop_original_event (type: boolean; default: false) — Drop the original combined event after emitting per-metric events.
• metric_field_name (type: string; default: "metric") — Field on each output event that stores the metric name.
• value_field_name (type: string; default: "value") — Field on each output event that stores the metric value.

Example configuration

filter {
  metricize {
    metrics             => [ "cpu_pct", "mem_pct", "disk_pct" ]
    metric_field_name   => "metric"
    value_field_name    => "value"
    drop_original_event => true
  }
}

Common options configuration

All Logstash filter plugins support these shared options:

• add_field (type: hash; default: {}) — Adds fields when the filter succeeds. Supports dynamic field names and values.
• add_tag (type: array; default: []) — Adds one or more tags when the filter succeeds.
• enable_metric (type: boolean; default: true) — Enables or disables metric collection for this plugin instance.
• id (type: string; default: none) — Sets an explicit plugin instance ID for monitoring and troubleshooting.
• periodic_flush (type: boolean; default: false) — Calls the filter flush method at regular intervals.
• remove_field (type: array; default: []) — Removes fields when the filter succeeds. Supports dynamic field names.
• remove_tag (type: array; default: []) — Removes tags when the filter succeeds.

filter {
  metricize {
    add_field => { "pipeline_stage" => "parsed" }
    add_tag => ["parsed", "logstash_filter"]
    enable_metric => true
    id => "my_filter_instance"
    periodic_flush => false
    remove_field => ["tmp_field"]
    remove_tag => ["temporary"]
  }
}

Apply in Logit.io

1. Open your stack in Logit.io and navigate to Logstash Pipelines.
2. In the filter { ... } section, add a metricize block.
3. Save your pipeline changes, then restart the Logstash pipeline if prompted.
4. Send sample events and verify parsed/enriched fields in OpenSearch Dashboards.

Validation checklist

• Confirm the metricize block compiles without syntax errors.
• Verify expected new/updated fields exist in sample documents.
• Verify unexpected fields are not removed unless explicitly configured.
• Confirm tags added on success/failure align with your alerting and routing rules.

Troubleshooting

• If events are unchanged, verify your filter condition (if ...) matches incoming events.
• If the pipeline fails to start, validate braces/quotes and retry with a minimal filter block.
• If throughput drops, reduce expensive operations and test with representative sample volume.

References

• GitHub package: logstash-filter-metricize (opens in a new tab)
• Canonical catalog: /log-management/ingestion-pipeline/logstash-filters-reference