Rspamd logging settings


Rspamd offers various logging options. Firstly, there are three supported types of log output: console logging, which outputs log messages to the console; file logging, which directs log messages to a file; and logging via the syslog daemon. Additionally, it is possible to limit logging to a specific level:

Level Description
error log only critical errors
warning log errors and warnings
notice log only important notices + scan messages results
info log all non-debug messages
silent log at info level on start and then reduce to notice level when forking worker processes
debug log all including debug messages (huge amount of logging)

You have the option to enable debug messages for specific IP addresses, which can be beneficial for testing purposes. Each logging type has specific mandatory parameters: log facility for syslog (refer to the syslog(3) man page for facility details), and log file for file logging. File logging can also be buffered for improved performance. In order to reduce logging noise, Rspamd detects consecutive matching log messages and replaces them with the total number of repeated occurrences.

#81123(fuzzy): May 11 19:41:54 rspamd file_log_function: Last message repeated 155 times
#81123(fuzzy): May 11 19:41:54 rspamd process_write_command: fuzzy hash was successfully added

Unique ID

Starting from version 1.0, Rspamd logs include a unique ID for each logging message, enabling efficient search for relevant messages. Additionally, there is now a module definition that specifies the module associated with the log message, such as task or cfg modules. Here is a brief example to illustrate how it works: let’s consider an incoming task for a specific message. In the logs, you would observe something similar to the following entry:

2015-09-02 16:41:59 #45015(normal) <ed2abb>; task; accept_socket: accepted connection from ::1 port 52895
2015-09-02 16:41:59 #45015(normal) <ed2abb>; task; rspamd_message_parse: loaded message; id: <>; queue-id: <undef>

In this case, the tag ed2abb is assigned to the task, and all subsequent processing related to that task will bear the same tag. This tagging feature is not limited to the task module alone; it is also enabled in other modules like spf or lua. For certain modules like cfg, the tag is generated statically using a specific characteristic, such as the checksum of the configuration file.

Configuration parameters

Here is a summary of the logging parameters, each of which can be redefined or defined in the local.d/ file:

Parameter Description
type Defines logging type (file, console or syslog). For some types mandatory attributes may be required.
filename Path to log file for file logging (required for file type)
facility Logging facility for syslog type (required if this type is used)
level Defines logging level (error, warning, info or debug).
log_buffered Flag that controls whether logging is buffered.
log_buf_size For file and console logging defines buffer size that will be used for logging output.
log_urls Flag that defines whether all URLs in message should be logged. Useful for testing. Default: false.
log_re_cache Output regular expressions statistics after each message. Default: true.
debug_ip List that contains IP addresses for which debugging should be turned on.
color Turn on coloring for log messages. Default: false.
systemd If true timestamps aren’t prepended to log messages. Default: false.
debug_modules A list of modules that are enabled for debugging.
log_usec Log microseconds (e.g. 11:43:16.68071). Default: false.
log_severity (2.8+) Log severity explicitly (e.g. [info] or [error]). Default: false.

Defined debug modules

Here is a list of C debug modules defined in Rspamd (this list is usually incomplete):

Module Description
bayes messages from Bayes classifier
cfg configuration messages
composites debug composite symbols
dkim messages from dkim module
dns messages from DNS resolver
fuzzy_backend messages from fuzzy backend
langdet messages from language detector
logger messages from the logger itself
main messages from the main process
map messages from maps in Rspamd
milter debug milter interface
protocol debug protocol details
proxy messages from proxy
spf messages from spf module
stat_redis messages from redis statistics
symcache messages from symbols cache
task task messages

Any Lua module can also be added to debug_modules as they are using somehow a similar naming semantics. E.g. you can use dkim_signing or multimap or lua_tcp to debug the corresponding modules.

Log format

Rspamd supports a custom log format for writing message information to the log. This feature has been supported since version 1.1. The format string for the custom log format is as follows:

log_format =<<EOD
id: <$mid>,$if_qid{ qid: <$>,}$if_ip{ ip: $,}$if_user{ user: $,}$if_smtp_from{ from: <$>,}
(default: $is_spam ($action): [$scores] [$symbols]),
len: $len, time: $time_real real,
$time_virtual virtual, dns req: $dns_req

Newlines are replaced with spaces in the custom log format. The log format line can include both text and variables. Each variable can have an optional if_ prefix, which will log the variable only if it is triggered. Additionally, each variable can have an optional body value where $ is replaced with the variable’s value. The $ placeholder can be repeated multiple times in the body. For example, $if_var{$$$$} will be replaced with the variable’s name repeated four times.

Log variables

Rspamd supports the following log variables:

Variable Description
action default metric action
digest cryptographic digest of a message’s content (stripped to 16 bytes or 32 hex symbols)
dns_req number of DNS requests
filename (from 1.8.0) name of file if HTTP agent (e.g. rspamc) passes it
forced_action (from 1.8.2) forced action if form <action> "<message>"; score=<score> (set by <module>)
groups (from 2.0) symbols groups list for a task
ip from IP
is_spam a one-letter rating of spammyness: T for spam, F for ham and S for skipped messages
len length of message
lua custom Lua script (see below)
mid message ID
mime_from MIME from
mime_rcpt MIME rcpt - the first recipient
mime_rcpts MIME rcpts - all recipients
public_groups (from 2.0) public groups only (similar to groups but more restricted)
qid queue ID
scores summary of scores
settings_id (from 2.0) settings id for a message
smtp_from envelope from (or MIME from if SMTP from is absent)
smtp_rcpt envelope rcpt (or MIME from if SMTP from is absent) - the first recipient
smtp_rcpts envelope rcpts - all recipients
symbols_params list of all symbols and their options
symbols_scores_params list of all symbols, their scores and options
symbols_scores list of all symbols and their scores
symbols list of all symbols
time_real real time of task processing
time_virtual (till 2.0) CPU time of task processing
user authenticated user

Custom logging scripts could look like the following:

  return function(task) 
    return 'text parts: ' .. tostring(#task:get_text_parts()) 

this script will log number of text part in messages.