Logio

Logio is a system for publishings log streams to a server and fanning them out to client subscriptions. It consists of a server and simple PUB/SUB client implementations. Configured apps publish logs to a topic via a TCP stream and clients subscribe to one or more topics for a live stream of logs. The result is similar experience to Heroku's log plexing service, only self-hosted.

Usage

Server

Spinning up a Logio server is as simple as the following:

$ docker run --rm -it -p 7701:7701 -p 7702:7702  kevincantwell/logio
Listening for subscribers on tcp :7702
Listening for publishers on tcp :7701

Publisher

A publisher is any app that produces logs. This project includes a Go package that will re-configure the default logger to publish logs to a server. Setting it up is as simple as importing the package and configuring a single connection string:

import _ "github.com/kevin-cantwell/logio"

$ export LOGIO_URL='logio://logio-server.example.com:7701?app=myapp&proc=web&host=foobar'

If you are familiar with Redis the connection string above will makes sense to you:

• logio is the schema and indicates that this is a Logio server we're connecting to
• logio-server.example.com is the domain where the Logio server is hosted.
• 7701 is the default port which handles log publications
• app, proc, and host define the topic to which logs are published. Only app is required. The proc and host values default to the name of the running process and the hostname, respecively. Usually only app and proc are specified.

Subscriber

A subscriber is any client that requests logs on one or more topics. A topic is composed of app, proc, and host. Subscribers may specify regex patterns that match multiple topics, thereby stitching multiple log streams into one (fan-out pattern).

The below subscription matches any apps named myapp with a process named either web or worker:

$ curl -N 'http://logio-server.example.com:7702?app=myapp&proc=web|worker'
2016-12-06T22:14:21.448 myapp[worker] i-10-45-22-14: 2016/12/06 17:14:21 INFO This is a worker log
2016-12-06T22:14:21.567 myapp[web] i-10-34-20-12: 2016/12/06 17:14:21 ERROR This is a web error
2016-12-06T22:14:21.782 myapp[web] i-10-34-20-12: 2016/12/06 17:14:21 INFO This is a web log
2016-12-06T22:14:21.901 myapp[web] i-10-34-20-12: 2016/12/06 17:14:21 INFO This is a web log

The output of a log subscription is formatted like so:

<timestamp> <app>[<proc>] <host>: <log>