de_dot filter plugin

Rewrites field names that contain . characters so they play nicely with OpenSearch. By default each dot is replaced with an underscore, producing a flat field name. With nested => true the dots are turned into sub-field boundaries instead, producing nested objects.

• Package: logstash-filter-de_dot
• Coverage source: default/bundled
• Official catalog entry: Yes

Plugin overview

de_dot is used in the Logstash filter stage. Removes dots from field names.

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: fields, nested, recursive, separator.

Options

Required

• No required plugin-specific options.

Optional

• fields (type: array; default: none) — Explicit list of field references to de-dot (for example ["process.name", "[foo][bar.suffix]"]). If omitted, every top-level field on the event is checked.
• nested (type: boolean; default: false) — When true, convert each dotted name into a nested sub-field instead of flattening with separator (the separator is forced to ][ internally, so setting both nested => true and separator at the same time is not useful).
• recursive (type: boolean; default: false) — When true, descend into hash-valued fields and de-dot nested keys as well. Expensive; only enable when you know the event can contain dotted keys inside nested objects.
• separator (type: string; default: "_") — Character used to replace each . in a field name when nested is false. Cannot itself contain a ..

Example configuration

filter {
  de_dot {
    fields    => [ "process.name", "container.image.name" ]
    separator => "_"
    recursive => false
  }
}
 
# Alternative: turn dotted names into nested sub-fields.
# filter {
#   de_dot {
#     fields => [ "process.name" ]
#     nested => 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 {
  de_dot {
    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 de_dot 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 de_dot 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-de_dot (opens in a new tab)
• Canonical catalog: /log-management/ingestion-pipeline/logstash-filters-reference