Add more logging framework documentation.

This commit is contained in:
Jon Siwek 2011-12-09 14:30:21 -06:00
parent 6d3b29b0ec
commit 1f57827e54
6 changed files with 272 additions and 59 deletions

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@ -1,16 +1,16 @@
##! The Bro logging interface.
##!
##! See XXX for a introduction to Bro's logging framework.
##! See :doc:`/logging` for a introduction to Bro's logging framework.
module Log;
# Log::ID and Log::Writer are defined in bro.init due to circular dependencies.
# Log::ID and Log::Writer are defined in types.bif due to circular dependencies.
export {
## If true, is local logging is by default enabled for all filters.
## If true, local logging is by default enabled for all filters.
const enable_local_logging = T &redef;
## If true, is remote logging is by default enabled for all filters.
## If true, remote logging is by default enabled for all filters.
const enable_remote_logging = T &redef;
## Default writer to use if a filter does not specify
@ -23,21 +23,24 @@ export {
columns: any;
## Event that will be raised once for each log entry.
## The event receives a single same parameter, an instance of type ``columns``.
## The event receives a single same parameter, an instance of type
## ``columns``.
ev: any &optional;
};
## Default function for building the path values for log filters if not
## speficied otherwise by a filter. The default implementation uses ``id``
## Builds the default path values for log filters if not otherwise
## specified by a filter. The default implementation uses *id*
## to derive a name.
##
## id: The log stream.
## id: The ID associated with the log stream.
##
## path: A suggested path value, which may be either the filter's
## ``path`` if defined, else a previous result from the function.
## If no ``path`` is defined for the filter, then the first call
## to the function will contain an empty string.
##
## rec: An instance of the streams's ``columns`` type with its
## fields set to the values to logged.
## fields set to the values to be logged.
##
## Returns: The path to be used for the filter.
global default_path_func: function(id: ID, path: string, rec: any) : string &redef;
@ -46,7 +49,7 @@ export {
## Information passed into rotation callback functions.
type RotationInfo: record {
writer: Writer; ##< Writer.
writer: Writer; ##< The :bro:type:`Log::Writer` being used.
fname: string; ##< Full name of the rotated file.
path: string; ##< Original path value.
open: time; ##< Time when opened.
@ -57,25 +60,26 @@ export {
## Default rotation interval. Zero disables rotation.
const default_rotation_interval = 0secs &redef;
## Default naming format for timestamps embedded into filenames. Uses a strftime() style.
## Default naming format for timestamps embedded into filenames.
## Uses a ``strftime()`` style.
const default_rotation_date_format = "%Y-%m-%d-%H-%M-%S" &redef;
## Default shell command to run on rotated files. Empty for none.
const default_rotation_postprocessor_cmd = "" &redef;
## Specifies the default postprocessor function per writer type. Entries in this
## table are initialized by each writer type.
## Specifies the default postprocessor function per writer type.
## Entries in this table are initialized by each writer type.
const default_rotation_postprocessors: table[Writer] of function(info: RotationInfo) : bool &redef;
## Filter customizing logging.
## A filter type describes how to customize logging streams.
type Filter: record {
## Descriptive name to reference this filter.
name: string;
## The writer to use.
## The logging writer implementation to use.
writer: Writer &default=default_writer;
## Predicate indicating whether a log entry should be recorded.
## Indicates whether a log entry should be recorded.
## If not given, all entries are recorded.
##
## rec: An instance of the streams's ``columns`` type with its
@ -101,13 +105,15 @@ export {
## easy to flood the disk by returning a new string for each
## connection ...
##
## id: The log stream.
## id: The ID associated with the log stream.
##
## path: A suggested path value, which may be either the filter's
## ``path`` if defined, else a previous result from the function.
## If no ``path`` is defined for the filter, then the first call
## to the function will contain an empty string.
##
## rec: An instance of the streams's ``columns`` type with its
## fields set to the values to logged.
## fields set to the values to be logged.
##
## Returns: The path to be used for the filter.
path_func: function(id: ID, path: string, rec: any): string &optional;
@ -129,27 +135,183 @@ export {
## Rotation interval.
interv: interval &default=default_rotation_interval;
## Callback function to trigger for rotated files. If not set,
## the default comes out of default_rotation_postprocessors.
## Callback function to trigger for rotated files. If not set, the
## default comes out of :bro:id:`Log::default_rotation_postprocessors`.
postprocessor: function(info: RotationInfo) : bool &optional;
};
## Sentinel value for indicating that a filter was not found when looked up.
const no_filter: Filter = [$name="<not found>"]; # Sentinel.
const no_filter: Filter = [$name="<not found>"];
# TODO: Document.
## Creates a new logging stream with the default filter.
##
## id: The ID enum to be associated with the new logging stream.
##
## stream: A record defining the content that the new stream will log.
##
## Returns: True if a new logging stream was successfully created and
## a default filter added to it.
##
## .. bro:see:: Log::add_default_filter Log::remove_default_filter
global create_stream: function(id: ID, stream: Stream) : bool;
## Enables a previously disabled logging stream. Disabled streams
## will not be written to until they are enabled again. New streams
## are enabled by default.
##
## id: The ID associated with the logging stream to enable.
##
## Returns: True if the stream is re-enabled or was not previously disabled.
##
## .. bro:see:: Log::disable_stream
global enable_stream: function(id: ID) : bool;
## Disables a currently enabled logging stream. Disabled streams
## will not be written to until they are enabled again. New streams
## are enabled by default.
##
## id: The ID associated with the logging stream to disable.
##
## Returns: True if the stream is now disabled or was already disabled.
##
## .. bro:see:: Log::enable_stream
global disable_stream: function(id: ID) : bool;
## Adds a custom filter to an existing logging stream. If a filter
## with a matching ``name`` field already exists for the stream, it
## is removed when the new filter is successfully added.
##
## id: The ID associated with the logging stream to filter.
##
## filter: A record describing the desired logging parameters.
##
## Returns: True if the filter was sucessfully added, false if
## the filter was not added or the *filter* argument was not
## the correct type.
##
## .. bro:see:: Log::remove_filter Log::add_default_filter
## Log::remove_default_filter
global add_filter: function(id: ID, filter: Filter) : bool;
## Removes a filter from an existing logging stream.
##
## id: The ID associated with the logging stream from which to
## remove a filter.
##
## name: A string to match against the ``name`` field of a
## :bro:type:`Log::Filter` for identification purposes.
##
## Returns: True if the logging stream's filter was removed or
## if no filter associated with *name* was found.
##
## .. bro:see:: Log::remove_filter Log::add_default_filter
## Log::remove_default_filter
global remove_filter: function(id: ID, name: string) : bool;
global get_filter: function(id: ID, name: string) : Filter; # Returns no_filter if not found.
## Gets a filter associated with an existing logging stream.
##
## id: The ID associated with a logging stream from which to
## obtain one of its filters.
##
## name: A string to match against the ``name`` field of a
## :bro:type:`Log::Filter` for identification purposes.
##
## Returns: A filter attached to the logging stream *id* matching
## *name* or, if no matches are found returns the
## :bro:id:`Log::no_filter` sentinel value.
##
## .. bro:see:: Log::add_filter Log::remove_filter Log::add_default_filter
## Log::remove_default_filter
global get_filter: function(id: ID, name: string) : Filter;
## Writes a new log line/entry to a logging stream.
##
## id: The ID associated with a logging stream to be written to.
##
## columns: A record value describing the values of each field/column
## to write to the log stream.
##
## Returns: True if the stream was found and no error occurred in writing
## to it or if the stream was disabled and nothing was written.
## False if the stream was was not found, or the *columns*
## argument did not match what the stream was initially defined
## to handle, or one of the stream's filters has an invalid
## ``path_func``.
##
## .. bro:see: Log::enable_stream Log::disable_stream
global write: function(id: ID, columns: any) : bool;
## Sets the buffering status for all the writers of a given logging stream.
## A given writer implementation may or may not support buffering and if it
## doesn't then toggling buffering with this function has no effect.
##
## id: The ID associated with a logging stream for which to
## enable/disable buffering.
##
## buffered: Whether to enable or disable log buffering.
##
## Returns: True if buffering status was set, false if the logging stream
## does not exist.
##
## .. bro:see:: Log::flush
global set_buf: function(id: ID, buffered: bool): bool;
## Flushes any currently buffered output for all the writers of a given
## logging stream.
##
## id: The ID associated with a logging stream for which to flush buffered
## data.
##
## Returns: True if all writers of a log stream were signalled to flush
## buffered data or if the logging stream is disabled,
## false if the logging stream does not exist.
##
## .. bro:see:: Log::set_buf Log::enable_stream Log::disable_stream
global flush: function(id: ID): bool;
## Adds a default :bro:type:`Log::Filter` record with ``name`` field
## set as "default" to a given logging stream.
##
## id: The ID associated with a logging stream for which to add a default
## filter.
##
## Returns: The status of a call to :bro:id:`Log::add_filter` using a
## default :bro:type:`Log::Filter` argument with ``name`` field
## set to "default".
##
## .. bro:see:: Log::add_filter Log::remove_filter
## Log::remove_default_filter
global add_default_filter: function(id: ID) : bool;
## Removes the :bro:type:`Log::Filter` with ``name`` field equal to
## "default".
##
## id: The ID associated with a logging stream from which to remove the
## default filter.
##
## Returns: The status of a call to :bro:id:`Log::remove_filter` using
## "default" as the argument.
##
## .. bro:see:: Log::add_filter Log::remove_filter Log::add_default_filter
global remove_default_filter: function(id: ID) : bool;
## Runs a command given by :bro:id:`Log::default_rotation_postprocessor_cmd`
## on a rotated file. Meant to be called from postprocessor functions
## that are added to :bro:id:`Log::default_rotation_postprocessors`.
##
## info: A record holding meta-information about the log being rotated.
##
## npath: The new path of the file (after already being rotated/processed
## by writer-specific postprocessor as defined in
## :bro:id:`Log::default_rotation_postprocessors`.
##
## Returns: True when :bro:id:`Log::default_rotation_postprocessor_cmd`
## is empty or the system command given by it has been invoked
## to postprocess a rotated log file.
##
## .. bro:see:: Log::default_rotation_date_format
## Log::default_rotation_postprocessor_cmd
## Log::default_rotation_postprocessors
global run_rotation_postprocessor_cmd: function(info: RotationInfo, npath: string) : bool;
}

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@ -1,29 +1,51 @@
##! This script defines a postprocessing function that can be applied
##! to a logging filter in order to automatically SCP (secure copy)
##! a log stream (or a subset of it) to a remote host at configurable
##! rotation time intervals.
##! rotation time intervals. Generally, to use this functionality
##! you must handle the :bro:id:`bro_init` event and do the following
##! in your handler:
##!
##! 1) Create a new :bro:type:`Log::Filter` record that defines a name/path,
##! rotation interval, and set the ``postprocessor`` to
##! :bro:id:`Log::scp_postprocessor`.
##! 2) Add the filter to a logging stream using :bro:id:`Log::add_filter`.
##! 3) Add a table entry to :bro:id:`Log::scp_destinations` for the filter's
##! writer/path pair which defines a set of :bro:type:`Log::SCPDestination`
##! records.
module Log;
export {
## This postprocessor SCP's the rotated-log to all the remote hosts
## Secure-copies the rotated-log to all the remote hosts
## defined in :bro:id:`Log::scp_destinations` and then deletes
## the local copy of the rotated-log. It's not active when
## reading from trace files.
##
## info: A record holding meta-information about the log file to be
## postprocessed.
##
## Returns: True if secure-copy system command was initiated or
## if no destination was configured for the log as described
## by *info*.
global scp_postprocessor: function(info: Log::RotationInfo): bool;
## A container that describes the remote destination for the SCP command
## argument as ``user@host:path``.
type SCPDestination: record {
## The remote user to log in as. A trust mechanism should be
## pre-established.
user: string;
## The remote host to which to transfer logs.
host: string;
## The path/directory on the remote host to send logs.
path: string;
};
## A table indexed by a particular log writer and filter path, that yields
## a set remote destinations. The :bro:id:`Log::scp_postprocessor`
## function queries this table upon log rotation and performs a secure
## copy of the rotated-log to each destination in the set.
## copy of the rotated-log to each destination in the set. This
## table can be modified at run-time.
global scp_destinations: table[Writer, string] of set[SCPDestination];
}

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@ -1,4 +1,5 @@
##! Interface for the ascii log writer.
##! Interface for the ASCII log writer. Redefinable options are available
##! to tweak the output format of ASCII logs.
module LogAscii;
@ -7,7 +8,8 @@ export {
## into files. This is primarily for debugging purposes.
const output_to_stdout = F &redef;
## If true, include a header line with column names.
## If true, include a header line with column names and description
## of the other ASCII logging options that were used.
const include_header = T &redef;
## Prefix for the header line if included.