TCP Syslog Module

Functions
M_log_error_t	M_log_module_add_tcp_syslog (M_log_t *log, const char *product, M_syslog_facility_t facility, const char *host, M_uint16 port, M_dns_t *dns, size_t max_queue_bytes, M_log_module_t **out_mod)
M_log_error_t	M_log_module_tcp_syslog_set_connect_timeout_ms (M_log_t *log, M_log_module_t *module, M_uint64 timeout_ms)
M_log_error_t	M_log_module_tcp_syslog_set_keepalives (M_log_t *log, M_log_module_t *module, M_uint64 idle_time_s, M_uint64 retry_time_s, M_uint64 retry_count)
M_log_error_t	M_log_module_tcp_syslog_set_tag_priority (M_log_t *log, M_log_module_t *module, M_uint64 tags, M_syslog_priority_t priority)

Detailed Description

Functions to enable logging to a remote syslog server over TCP.

This module formats messages according to the legacy BSD syslog format from RFC 3164, and adds octet-counting framing as described in RFC 6587 for transmission over TCP. This legacy format was chosen to ensure compatibility across a wide range of syslog servers.

Messages are written asynchronously, as part of an existing event loop owned by the caller.

Note: syslog messages are limited to 1024 chars / line. Lines longer than this will be truncated.

Function Documentation

M_log_module_add_tcp_syslog()

M_log_error_t M_log_module_add_tcp_syslog	(	M_log_t *	log,
		const char *	product,
		M_syslog_facility_t	facility,
		const char *	host,
		M_uint16	port,
		M_dns_t *	dns,
		size_t	max_queue_bytes,
		M_log_module_t **	out_mod
	)

Add a module to output to a remote syslog server over TCP.

This module formats messages according to the legacy BSD syslog format from RFC 3164, and adds octet-counting framing as described in RFC 6587 for transmission over TCP. This legacy format was chosen to ensure compatibility across a wide range of syslog servers.

Note: syslog messages are limited to 1024 chars / line. Lines longer than this will be truncated.

Parameters

[in]	log	logger object
[in]	product	short tag string for syslog, usually the name of the program sending log info
[in]	facility	facility type to associate with all log messages, gets passed directly to syslog
[in]	host	hostname of destination syslog server
[in]	port	port of destination syslog server (usually 514)
[in]	dns	external DNS resolver cache to use (not owned by logger)
[in]	max_queue_bytes	max size of queue used to buffer asynchronous writes to syslog
[out]	out_mod	handle for created module, or NULL if there was an error

Returns

error code

M_log_module_tcp_syslog_set_connect_timeout_ms()

M_log_error_t M_log_module_tcp_syslog_set_connect_timeout_ms	(	M_log_t *	log,
		M_log_module_t *	module,
		M_uint64	timeout_ms
	)

Set TCP connection timeout.

Note that, in addition to normal connection parameters, the TCP module will automatically try to reconnect on disconnect or error after a short delay, no matter what you set here.

Parameters

[in]	log	logger object
[in]	module	handle of module to operate on
[in]	timeout_ms	connection timeout, in milliseconds

Returns

error code

M_log_module_tcp_syslog_set_keepalives()

M_log_error_t M_log_module_tcp_syslog_set_keepalives	(	M_log_t *	log,
		M_log_module_t *	module,
		M_uint64	idle_time_s,
		M_uint64	retry_time_s,
		M_uint64	retry_count
	)

Set TCP keep alive parameters for the connection.

If this function isn't called, the following default values are used:

• idle_time_s = 4 seconds
• retry_time_s = 15 seconds
• retry_count = 3

Parameters

[in]	log	logger object
[in]	module	handle of module to operate on
[in]	idle_time_s	tcp idle timeout, in seconds
[in]	retry_time_s	tcp retry time, in seconds
[in]	retry_count	tcp allowed number of retries

Returns

error code

M_log_module_tcp_syslog_set_tag_priority()

M_log_error_t M_log_module_tcp_syslog_set_tag_priority	(	M_log_t *	log,
		M_log_module_t *	module,
		M_uint64	tags,
		M_syslog_priority_t	priority
	)

Associate the given user-defined tag(s) with a syslog priority tag.

If you don't associate a tag with a syslog priority, the default priority of M_SYSLOG_INFO will be used for that tag.

See also

M_LOG_ALL_TAGS

M_log_all_tags_lt

M_log_all_tags_lte

M_log_all_tags_gt

M_log_all_tags_gte

Parameters

[in]	log	logger object
[in]	module	handle of module to operate on
[in]	tags	user-defined power-of-two tag (or multiple power-of-two tags, OR'd together)
[in]	priority	single priority value to associate with the given tags

Returns

error code