Does my Sinatra API application need a class declaration? - ruby

Question

Someone developed an API application for me that works well. Unfortunately, it doesn't log anywhere and there are no logs at all. The app runs with the "rackup" command and sits behind an nginx web server. The Sinatra errors are not logged to the nginx logs.
The app.rb file looks something like this:
require './libs'
require 'sinatra'
require 'sinatra/namespace'
set :bind, '::1'
before do
content_type :json
headers 'Access-Control-Allow-Origin' => '*', 'Access-Control-Allow-Methods' => ['OPTIONS', 'GET', 'POST']
end
namespace '/api/v1' do
namespace '/getit/:thingtoget' do
helpers do
def myhelper1
<stuff>
end
def myhelper1
<stuff>
end
end
before do
myhelper1
myhelper2
end
get '/info' do
WidgetDomain::get_info(#va1, #var2).to_json
end
<more API paths here>
end
Now this is working fine. But now I want to introduce logging. So I looked at the Sinatra README and it said I could enable logging like so:
class MyApp < Sinatra::Base
configure :production, :development do
enable :logging
end
end
Do I put that above the namespace stuff? If I declare an app like that, does my namespace stuff need to be inside that app code somehow? I don't have a grasp of how this works at all.
It almost looks like it's trying to log in the nginx log, but here's what an error line looks like there:
2018/12/30 19:53:15 [error] 6615#0: *21522 connect() failed (111: Connection refused) while connecting to upstream, client: <someip>, server: api.example.com, request: "GET /api/v1/getit/thingtoget1/stuff/var1/var2/var3 HTTP/1.1", upstream: "http://[::1]:9292/api/v1/getit/thingtoget/stuff/var1/var2/var3", host: "api.example.com", referrer: "an HTML page from the nginx server"
It's almost like it's trying to connect back to the server to retrieve a message or something. But in case the logging has something to do with the way I've declared the server in the nginx configuration, here it is:
server {
listen 443;
listen [::]:443;
server_name api.myapp.com;
ssl on;
ssl_certificate /etc/nginx/ssl/myapp_com.pem;
ssl_certificate_key /etc/nginx/ssl/star_myapp_com.key;
location / {
proxy_pass http://localhost:9292;
}
}

Answer 1

Have a look at Sinatra's README in the Logging section but I tend to set up a logger outside of the Sinatra app in case other bits get bolted on or several apps are used together and I can use the same logger for all of them. Simplest way is a global variable (one of the few places they're acceptable, but it's not the only way) :
require 'mono_logger' # because it's thread safe
require 'pathname' # because paths aren't strings :)
log_path = Pathname(__dir__).join("logs/app.log")
$logger = MonoLogger.new(log_path)
$logger.level = MonoLogger::INFO
Then in a route or wherever:
get '/' do
$logger.info "here"
In my terminal:
$ cat logs/app.log
I, [2019-01-07T13:03:52.989415 #64378] INFO -- : here
As to configuration blocks, you don't need to worry about putting them within a class declaration unless you're using a modular app (see Modular vs. Classic Style in the README) and yours is in the classic style.
Configuration blocks aren't namespaced (Sinatra::Namespace handles things that take a route as an argument, like get and before) so follow convention and stick it near the top of the file.
Hope that helps.