Log Provider

You can write a custom log provider and configure the OpenFaaS Gateway to use it.

A log provider is an HTTP server that provides a /system/logs endpoint that supports a GET request with the following query parameters

• name : the function name and is required
• instance : the optional container name, that allows you to request logs from a specific function instance
• since : the optional datetime value to start the logs from
• tail : sets the maximum number of log messages to return, <=0 means unlimited
• follow : allows the user to request a stream of logs until the timeout

When follow is true, the server must use HTTP chunked-encoding to send a live stream of the logs.

Configure the log provider

The gateway will proxy log requests to the function provider, by default. To use an alternative log provider, simply set the logs_provider_url environment variable in your gateway server. The gateway will then proxy the logs requests to this URL.

Available providers

• faas-netes is the Kubernetes provider and queries logs from the Kubernetes API

• faasd queries the logs from the journal, stored by functions and core services

• openfaas-loki is a community provider which uses Grafana Loki to collection and query the function logs

Create a new log provider

The github.com/openfaas/faas-provider/logs package provides a Go interface and utilities to simplify the creation of a new log provider. Once you hae implemented the Requester interface the other package utilities can be used to create the required http server. A very simple “static” logs example can be found in the faas-provider repo.