tcp-logger

tcp-logger

Ships a JSON access-log entry for each request/response to a remote TCP endpoint (Logstash, Fluentd, a raw TCP collector, ...). Entries are buffered in a batch sink and delivered by a background task that opens a fresh TCP connection 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 — it never blocks on the network. Place this node in the response pipeline after the upstream node, so the final status, latency, and body size are available.

Configuration

Key	Type	Default	Description
host	string	— (required)	TCP server hostname or IP.
port	integer	— (required)	TCP server port (0–65535).
timeout	integer (ms)	1000	Connect/send timeout.
tls	bool	false	Not yet supported — true is rejected at config load.
tls_options	string	—	Accepted but ignored (TLS unsupported).
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; 1 flushes every entry immediately.
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 flush.
retry_delay	integer (s)	1	Delay between retries.
max_pending_entries	integer	10000	Queue capacity; entries are dropped (with a warning) when full.

- id: tcp-log
  type: tcp-logger
  config:
    host: 127.0.0.1
    port: 5044
    timeout: 1000
    batch_max_size: 100

Behavior

Builds the shared access-log entry (default structured object, or the flat log_format object when configured), pushes it to the batch sink, and passes the context through unchanged. The node is a pure passthrough: it never modifies the context and never fails, so only its success port is ever taken. A failed TCP flush is retried per the batch keys and otherwise logged and dropped.

Behavior notes

• Entries are always sent as newline-delimited JSON (one object per line). The wire format is stable regardless of batching.
• tls / tls_options are not yet supported; tls: true is rejected. Plain TCP only.