Dependencies

MongoLog itself depends on MongoDB (of course) and the Perl bindings. The scripts to filter and format logs are in Python and thus depend on the Python bindings.

MongoDB (package: mongodb) is in Ubuntu as of Lucid. The Python bindings (python-pymongo) are available as of Maverick. The Perl bindings (libmongodb-perl) will be available starting in Oneiric. If you are running an insufficiently new version of Ubuntu, http://www.mongodb.org/display/DOCS/Ubuntu+and+Debian+packages or http://web.onassar.com/blog/2011/01/19/installing-mongodb-on-ubuntu-10-10/ may be useful if you want packages to install.

Installing

To install the module, you need to symlink the reposity in to ~/.owl/modules/MongoLog/ (so the path to the module source file will be ~/.owl/modules/MongoLog/lib/BarnOwl/Module/MongoLog.pm). You may also want symlink scripts/mongolog into your path. mongolog foo calls the appropriate mongolog-foo command in the scripts directory, similarly to how git operates. To add new mongolog subcommands, you can either add to the scripts directory or place them anywhere in your path.

Configuring

To configure MongoLog in BarnOwl, you can set the mongolog:enable (default: off), mongolog:host (default: localhost:41803), mongolog:database (default: barnowl), mongolog:username (default: none), or mongolog:password (default: none) variables.

Alternatively, if you create a file called ~/.owl/mongolog.json, the BarnOwl module will automatically load any parameters specified there. (In particular, it will copy them to the corresponding BarnOwl variables on startup. You can override them per-session with the :set command as usual.)

For example, one valid ~/.owl/mongolog.json would be:

{
    "mongolog" : {
        "host" : "localhost",
        "database" : "barnowl",
        "username" : "foo",
        "password" : "bar"
    }
}

If you wish to use scripts/mongolog-filter, you will need to create ~/.owl/mongolog.json.

mongolog subcommands

filter

filter retrieves log entries from the database and dumps them as JSON to stdout. It takes various options to limit what gets displayed.

format

format takes JSON documents on stdin, and formats them according to one of two predefined formats --- log, which looks like a normal BarnOwl log entry; and style:default, which looks somewhat similar to the default BarnOwl style. To select which style, either pass it as the first argument on the commandline, or define the default_format key in your ~/.owl/mongolog.json.

latest

latest just pipes filter into format for you. filter is run with --limit 20 and any arguments that you provide on the commandline of latest. format will be run with no arguments. If you prefer style:default, this means you may want to set your default_format.

Tuning

You may find that running mongolog filter is a bit slow. I found adding indices to improve matters substantially:

db.messages.ensureIndex({"time": 1})
db.messages.ensureIndex({"class": 1})

Even after, it was a little on the slow side, but the indices made it better --- times dropped from about two seconds to about 3/4 second in my highly unscientific test.