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Cribl LogStream Documentation

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Cribl LogStream supports receiving of data over TCP. (See examples and header options below.)


Type: Push | TLS Support: YES | Event Breaker Support: YES

Configuring Cribl LogStream to Receive TCP Data

Select Data > Sources, then select TCP from the DataĀ Sources page's tiles or left menu. Click Add New to open the TCP > New Source modal, which provides the fields outlined below.


LogStream ships with a TCP Source preconfigured to listen on PortĀ 10060. You can clone or directly modify this Source to further configure it, and then enable it.

General Settings

Input ID: Enter a unique name to identify this TCP Source definition.

Address: Enter hostname/IP to listen for raw TCP data. E.g., localhost or

Port: Enter port number.

IP whitelist regex: Regex matching IP addresses that are allowed to establish a connection. Defaults to .* (i.e,. all IPs).

Enable Header: Toggle to Yes to indicate that client will pass a header record with every new connection. TheĀ header can contain an authToken, and an object with a list of fields and values to add to every event. TheseĀ fields can be used to simplify EventĀ Breaker selection, routing, etc. HeaderĀ format:
{ "authToken" : "myToken", "fields": { "field1": "value1", "field2": "value2" }}.

  • Shared secret (authToken): Shared secret to be provided by any client (in authToken header field). ClickĀ Generate to create a new secret. If empty, unauthenticated access will be permitted.

TLS Settings (Server Side)

Enabled defaults to No. When toggled to Yes:

Certificate name: Name of the predefined certificate.

Private key path: Path on server where to find the private key to use in PEM format. Path can reference $ENV_VARS.

Passphrase: Passphrase to use to decrypt private key.

Certificate path: Server path at which to find certificates (in PEM format) to use. PathĀ can reference $ENV_VARS.

CA certificate path: Server path at which to find CA certificates (in PEM format) to use. PathĀ can reference $ENV_VARS.

Authenticate client (mutual auth): Require clients to present their certificates. Used to perform mutual authentication using SSL certs. Defaults to No. When toggled to Yes:

  • Validate client certs: Reject certificates that are not authorized by a CA in the CAĀ certificate path, or by another trusted CA (e.g., the system's CA). Defaults toĀ No.

  • Common name: Regex matching subject common names in peer certificates allowed to connect. DefaultsĀ toĀ .*. Matches on the substring after CN=. AsĀ needed, escape regex tokens to match literal characters. E.g., to match the subject CN=worker.cribl.local, you would enter: worker\.cribl\.local.

Minimum TLS version: Optionally, select the minimum TLS version to accept from connections.

Maximum TLS version: Optionally, select the maximum TLS version to accept from connections.

Processing Settings

Custom Command

In this section, you can pass the data from this input to an external command for processing before the data continues downstream.

Enabled: Defaults to No. When toggled to Yes:

Command: Enter the command that will consume the data (via stdin) and will process its output (via stdout).

Arguments: Click + Add Argument to add each argument for the command. You can drag arguments vertically to resequence them.

Event Breakers

Event Breaker rulesets: A list of event breaking rulesets that will be applied to the input data stream before the data is sent through the Routes. Defaults to System Default Rule.

Event Breaker buffer timeout: The amount of time (in milliseconds) that the event breaker will wait for new data to be sent to a specific channel, before flushing out the data stream, as-is, to the Routes. Defaults to 10000.

Fields (Metadata)

In this section, you can add fields/metadata to each event using Eval-like functionality.

  • Name: Field name.
  • Value: JavaScript expression to compute field's value (can be a constant).


In this section's Pipeline drop-down list, you can select a single existing Pipeline to process data from this input before the data is sent through the Routes.

Advanced Settings

Enable proxy protocol: Defaults to No. Toggle to Yes if the connection is proxied by a device that supports ProxyĀ Protocol V1 or V2.

Internal Fields

Cribl LogStream uses a set of internal fields to assist in handling of data. These "meta" fields are not part of an event, but they are accessible, and functions can use them to make processing decisions.

Fields accessible for this Source:

  • __inputId
  • __srcIpPort
  • __channel

TCP Source Example

Every new TCP connection may contain an optional header line, with an authToken and a list of fields and values to add to every event.

{"authToken":"myToken42", "fields": {"region": "us-east-1", "AZ":"az1"}}

this is event number 1
this is event number 2

Enabling the Example

  1. Configure LogStream to listen on port 7777 for raw TCP. Set authToken to myToken42.
  2. Create a file called test.raw, with the payload above.
  3. Send it over to your Cribl LogStream host, using this command: cat test.raw | nc <myCriblHost> 7777

Updated about a month ago


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