Using redis_logger for application logging

I just pushed a new project to github, redis_logger. I decided to give this a go and see if it ended up as potentially useful as I thought it might, and I’m pretty pleased with its initial version, limited though it is.

The idea is that by installing the tiny gem you can add logging into Redis to your application, including the ability to group log entries together, and then browse the groups, including intersections between groups.

As an example: let’s say you do like I did, which is to add request logging to your Rails application. I added this to my application_controller.rb:

  before_filter :log_request

  def log_request
    RedisLogger.debug({ "request" => request.url,
                        "remote_ip" => request.remote_ip,
                        "user_id" =>,
                        "username" =>
    }, "requests")

This will create a log entry as a Hash in Redis, containing the key/value pairs that were passed in. A “timestamp” value is also automatically added for you. This entry will be added into two groups, “debug” and “requests” — the “requests” group is passed into the call as the optional second parameter.

I could also add a call in my controller to log a warning if a user tries to access a page and is redirected to the signin page, or an error if an exception is passed up. I could then view all of the log entries in the intersection of “error” and “requests” to see only errors logged in the “requests” group, and not the debug or warn messages.

One of the great things about this is that it was so easy to do using Redis, once I worked out the approach. Using Sets, the code stores the entries and then adds them to the log groups as sets. Using Hashes, each entry is stored with its key/value pairs intact. I’m thinking about things l ike adding some more standard keys, like the current “timestamp” key, and enabling some additional functionality like adding tags for additional searchability within the groups.

Having the log entries in Redis is great, but browsing them is the fun part. So, there’s also redis_logger-web, a simple Sinatra app that lists the groups and lets you view the log entries. You can click on a group name to see its entries, most recent to oldest, or you can select multiple groups and view the intersection of their entries. Right now that’s limited to just the most recent 100 entries, until I work out the best way to save temporary sets and clean them up in a cron. In reality, though, the most recent 100 entries is what’s generally useful. Adding export functionality is first on my list, because that will be extremely handy for analysis.

Scaling, testing, and adding the essential multi-threading are next, of course. Sound interesting? Please, grab it, fork it, enhance it, let me know what you think.


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