cowolg

Access logs for cowboy.

Description

This OTP application provides a onresponse fun for building access logs and sending them using syslog via TCP. The example use case is the following:

+----------------+                      +-------------------+
| Your webserver |   ------ TCP ------> | Rsyslog/Syslog NG |
+----------------+                      +-------------------+

Installation

Add the library to your rebar.config or your Makefile (if you use erlang.mk) and compile it. Then add it to your .app.src like this:

{application, junk, [
    % [...]
    {applications, [
        kernel,
        stdlib,
        cowboy,
        cowolg
    ]},
    % [...]
]}.

In your cowboy router declare a onresponse fun like this:

% [...]

{ok, _} = cowboy:start_http(http, 1, [{port, 8000}], [
    {env, [{dispatch, Routes}]},
    {onresponse, fun cowolg:push/4}
]),

Configuration

Cowolg support the following configuration:

    {filters, [
        {accepted_headers, []},
        {accepted_qs_vals, []}
    ]},

    {worker, [
        {bucket_size, 100}
    ]},

    {flusher, [
        {tcp_host, "localhost"},
        {tcp_port, 1234}
    ]}

Cowolg will filter any request and response headers which are not listed in filters/acccepter_headers before sending logs. The same behaviour is applied for query string arguments, vie filters/accepted_qs_vals. bucket_size control the in memory buffer size the worker process must be before flushing logs. flusher/tcp_host|tcp_port control the tcp host and port flusher process must connect to. The TCP server must be up and running before starting cowolg.