Dedupe events

Deduplicate events passing through a topology, i.e. eliminate any events with duplicated content within a specified time window

status: stable egress: stream state: stateful

Configuration

Example configurations 

{
  "transforms": {
    "my_transform_id": {
      "type": "dedupe",
      "inputs": "my-source-or-transform-id"
    }
  }
}
[transforms.my_transform_id]
type = "dedupe"
inputs = "my-source-or-transform-id"

---
transforms:
  my_transform_id:
    type: dedupe
    inputs: my-source-or-transform-id
    fields: null

{
  "transforms": {
    "my_transform_id": {
      "type": "dedupe",
      "inputs": "my-source-or-transform-id"
    }
  }
}
[transforms.my_transform_id]
type = "dedupe"
inputs = "my-source-or-transform-id"

---
transforms:
  my_transform_id:
    type: dedupe
    inputs: my-source-or-transform-id
    cache: null
    fields: null

cache

optional object
Options controlling how we cache recent Events for future duplicate checking.

cache.num_events

optional uint
The number of recent Events to cache and compare new incoming Events against.
default: 5000

fields

required object
Options controlling what fields to match against.

fields.ignore

optional array
The field names to ignore when deciding if an Event is a duplicate. Incompatible with the fields.match option.

fields.match

optional array
The field names considered when deciding if an Event is a duplicate. This can also be globally set via the global log_schema options. Incompatible with the fields.ignore option.
default: [timestamp host message]

inputs

required [string]

A list of upstream source or transform IDs. Wildcards (*) are supported but must be the last character in the ID.

See configuration for more info.

Array string literal
Examples 
[
  "my-source-or-transform-id",
  "prefix-*"
]

Telemetry

Metrics

link

events_discarded_total

counter
The total number of events discarded by this component.

events_in_total

counter
The number of events accepted by this component either from tagged origin like file and uri, or cumulatively from other origins.
component_kind required
The Vector component kind.
component_name required
The Vector component name.
component_type required
The Vector component type.
container_name optional
The name of the container from which the event originates.
file optional
The file from which the event originates.
mode optional
The connection mode used by the component.
peer_addr optional
The IP from which the event originates.
peer_path optional
The pathname from which the event originates.
pod_name optional
The name of the pod from which the event originates.
uri optional
The sanitized URI from which the event originates.

events_out_total

counter
The total number of events emitted by this component.
component_kind required
The Vector component kind.
component_name required
The Vector component name.
component_type required
The Vector component type.

processed_bytes_total

counter
The number of bytes processed by the component.
component_kind required
The Vector component kind.
component_name required
The Vector component name.
component_type required
The Vector component type.
container_name optional
The name of the container from which the bytes originate.
file optional
The file from which the bytes originate.
mode optional
The connection mode used by the component.
peer_addr optional
The IP from which the bytes originate.
peer_path optional
The pathname from which the bytes originate.
pod_name optional
The name of the pod from which the bytes originate.
uri optional
The sanitized URI from which the bytes originate.

processed_events_total

counter
The total number of events processed by this component. This metric is deprecated in place of using events_in_total and events_out_total metrics.
component_kind required
The Vector component kind.
component_name required
The Vector component name.
component_type required
The Vector component type.

How it works

Cache Behavior

This transform is backed by an LRU cache of size cache.num_events. That means that this transform will cache information in memory for the last cache.num_events Events that it has processed. Entries will be removed from the cache in the order they were inserted. If an Event is received that is considered a duplicate of an Event already in the cache that will put that event back to the head of the cache and reset its place in line, making it once again last entry in line to be evicted.

Memory Usage Details

Each entry in the cache corresponds to an incoming Event and contains a copy of the ‘value’ data for all fields in the Event being considered for matching. When using fields.match this will be the list of fields specified in that configuration option. When using fields.ignore that will include all fields present in the incoming event except those specified in fields.ignore. Each entry also uses a single byte per field to store the type information of that field. When using fields.ignore each cache entry additionally stores a copy of each field name being considered for matching. When using fields.match storing the field names is not necessary.

Memory Utilization Estimation

If you want to estimate the memory requirements of this transform for your dataset, you can do so with these formulas:

When using fields.match:

Sum(the average size of the *data* (but not including the field name) for each field in `fields.match`) * `cache.num_events`

When using fields.ignore:

(Sum(the average size of each incoming Event) - (the average size of the field name *and* value for each field in `fields.ignore`)) * `cache.num_events`

Missing Fields

Fields with explicit null values will always be considered different than if that field was omitted entirely. For example, if you run this transform with fields.match = ["a"], the event “{a: null, b:5}” will be considered different to the event “{b:5}”.

State

This component is stateful, meaning its behavior changes based on previous inputs (events). State is not preserved across restarts, therefore state-dependent behavior will reset between restarts and depend on the inputs (events) received since the most recent restart.
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