Default logging format improvements

[thibaultcha]

The default logging format currently provides:

local message = {
  request = {
    headers = ngx.req.get_headers(),
    size = ngx.var.request_length
  },
  response = {
    headers = ngx.resp.get_headers(),
    size = ngx.var.body_bytes_sent
  },
  authenticated_entity = ngx.ctx.authenticated_entity,
  api = ngx.ctx.api,
  ip = ngx.var.remote_addr,
  status = ngx.status,
  url = ngx.var.uri,
  started_at = ngx.ctx.started_at
}

As mentioned by @jeevanrd in #226, this does not log the query parameters. I could see some improvements to the format, by adding more informations:

local message = {
  request = {
    uri = ngx.var.uri, -- only the path
    request_uri = ngx.var.request_uri, -- full request + parameters
    args = ngx.req.get_uri_args(), -- parameters, as a table
    method = ngx.req.get_method(), -- http method
    headers = ngx.req.get_headers(),
    size = ngx.var.request_length
  },
  response = {
    status = ngx.status, -- moved to response
    headers = ngx.resp.get_headers(),
    size = ngx.var.bytes_sent -- apparently not documented but does work for the APIAnalytics plugin (full size, not just body)
  },
  authenticated_entity = ngx.ctx.authenticated_entity,
  api = ngx.ctx.api,
  client_ip = ngx.var.remote_addr, -- rename the property
  started_at = ngx.req.start_time(), -- native method
  proxy_started_at = ngx.ctx.proxy_started_at,
  proxy_ended_at = ngx.ctx.proxy_ended_at
}

How does that sound? No logging of the bodies tho.

See http://wiki.nginx.org/HttpCoreModule#Variables and http://wiki.nginx.org/HttpLuaModule for details about each property.

[subnetmarco]

@thibaultcha I have implemented the above format, and wrote a small documentation in the logging plugin pages of the getkong.org 0.3.0 branch. Should we close this issue?

[thibaultcha]

Yeah sounds good. It's moved to a serializer in he Analytics PR and I'll probably add some more timing infos. If you wrote some doc for it, check the related box at Kong/docs.konghq.com#86