file-logger

file-logger

Appends a JSON access-log entry for each request/response to a local file. Entries are handed to a batch sink; a background task opens the target file in append mode per flush and writes each entry as one newline-delimited JSON object.

Delivery is fire-and-forget: execute builds the entry, hands it to the sink, and returns the context unchanged. Place this node in the response pipeline after the upstream node.

Configuration

Key	Type	Default	Description
path	string	— (required)	Target file path. Opened in append mode; created if absent. Its parent directory must already exist.
log_format	object	—	Custom name -> "$var" entry; replaces the default structured entry.
include_req_body	bool	false	Add the request body to the default entry.
include_resp_body	bool	false	Add the response body to the default entry.
batch_max_size	integer	1000	Entries per batch; set 1 for immediate per-request writes.
inactive_timeout	integer (s)	5	Flush when idle this long.
buffer_duration	integer (s)	60	Flush when the oldest buffered entry is this old.
max_retry_count	integer	0	Retries after a failed write.
retry_delay	integer (s)	1	Delay between retries.
max_pending_entries	integer	10000	Queue capacity; entries are dropped (with a warning) when full.

- id: file-log
  type: file-logger
  config:
    path: /var/log/featherbit/access.log
    batch_max_size: 1

Behavior

Builds the shared access-log entry, pushes it to the batch sink, and passes the context through unchanged. The node is a pure passthrough: only its success port is ever taken. If the file cannot be opened or written (for example, a missing parent directory), the flush fails and is retried/dropped per the batch keys.

Behavior notes

• Writes are routed through the shared batch sink for consistency with the other loggers. Set batch_max_size: 1 to write every entry as it arrives.
• The parent directory is not created: if it is missing the flush fails. The file itself is created if absent.