Highlights

• distributed nodes broadcast log messages to a central disk log
• configure the max size and number of files in your rotating disk log
• filter log messages into partitioned "buckets" based on node names, log types, and regexp matching
• full featured web application for log monitoring and greping
• extendable via event_handler registration for custom log routing

ABOUT

Log_roller is based on a publisher/subscriber model. It integrates seamlessly with existing systems without the need to change code. Nodes designated as publishers (these are your app nodes running the log_roller application) broadcast log messages sent to their error_logger to nodes designated as subscribers (these are nodes running the log_roller_server application that collect log messages and write them to a rotating disk log).

Publishers and subscribers perform an auto-discovery step upon booting. During startup, nodes of either type (publisher or subscriber) will attempt to connect. Make sure to have matching ~/.erlang.cookie files hosted on the servers running log_roller and log_roller_server. The nodes will not be able to see each other otherwise.

Dependencies

mochiweb http://github.com/clones/mochiweb

Installation

Either clone the repository github.com/JacobVorreuter/log_roller or download the tarball from jacobvorreuter.github.com/log_roller and run

make
sudo make install

Integration

To begin logging messages with log_roller, simply start the log_roller application. This can be done either in the app file of your application:

{application, my_app, [
    {description, "my_app"},
    {vsn, "0.4"},
    {modules, []},
    {registered, []},
    {mod, {my_app, []}},
    {applications, [kernel, stdlib, log_roller]}
]}.

-or-

you can just start log_roller from somewhere in your app:

log_roller:start()

Nodes with log_roller enabled will automatically ping visible log_roller_server nodes to establish a connection.

---

To start a subscriber node, you must either use the log_roller_server boot script or start the log_roller_server application.

/etc/init.d/log_roller start server

-or-

erl -name server@hostname -boot log_roller_server

-or-

{application, my_app, [
    {description, "my_app"},
    {vsn, "0.4"},
    {modules, []},
    {registered, []},
    {mod, {my_app, []}},
    {applications, [kernel, stdlib, log_roller_server]}
]}.

-or-

log_roller_server:start()

CONFIGURATION

There is a config file, "log_roller.config" located in the priv directory. This will be installed to the priv directory in the log_roller_server lib directory inside your otp root directory. For instance: /usr/lib/erlang/lib/log_roller_server-0.3/priv/log_roller.config. This contains the path to the log directory as well as max file size and number of rotating log files.

Simple Example

[{log_roller_server, [
	{cache_size, 65536},
	{maxbytes, 10485760},
	{maxfiles, 10}
]}].

Filtering to Multiple Buckets

[{log_roller_server, [
	{logs, [
		{first, [
			{cache_size, 65536},
			{maxbytes, 10485760},
			{maxfiles, 10},
			{filters, [
				{nodes, ['foo@MyDogJesusMac.local', 'ack@MyDogJesusMac.local']}
			]}
		]},
		{second, [
			{cache_size, 65536},
			{maxbytes, 10485760},
			{maxfiles, 10},
			{filters, [
				{nodes, ['bar@MyDogJesusMac.local']},
				{types, [error, warning]}
			]}
		]},
		{third, [
			{cache_size, 65536},
			{maxbytes, 10485760},
			{maxfiles, 10},
			{filters, [
				{nodes, ['baz@MyDogJesusMac.local']},
				{type, [progress, info]},
				{grep, "log_roller"}
			]}
		]}
	]}		
]}].

LICENSE

Copyright (c) 2009 Jacob Vorreuter <jacob.vorreuter@gmail.com>

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.