crfa-prometheus-http-gateway.rb

require 'webrick'
require 'faraday'
require 'json'

server = WEBrick::HTTPServer.new(
    :Port => 8082,
    :SSLEnable => false,
    :ServerSoftware => '¯\_(ツ)_/¯'
)

puts "Configured urls:"
ARGV.each { |url| puts url }

def filterMetrics(body)
    obj = { }

    body.each_line { | line | 
        if line.start_with?('node_directory_size_bytes')
            split = line.gsub(/\s+/m, ' ').strip.split(" ")

            obj[:cardanoDbSize] = split[1].strip
        end
        if line.start_with?('cardano_node_metrics_density_real')
            split = line.gsub(/\s+/m, ' ').strip.split(" ")

            obj[:chainDensity] = split[1].strip
        end
        if line.start_with?('cardano_node_metrics_utxoSize_int')
            split = line.gsub(/\s+/m, ' ').strip.split(" ")

            obj[:utxoSize] = split[1].strip
        end
        if line.start_with?('cardano_node_metrics_delegMapSize_int')
            split = line.gsub(/\s+/m, ' ').strip.split(" ")

            obj[:delegMapSize] = split[1].strip
        end
        if line.start_with?('cardano_node_metrics_forks_int')
            split = line.gsub(/\s+/m, ' ').strip.split(" ")

            obj[:chainForks] = split[1].strip
        end
    }

    return obj.to_json
end

server.mount_proc '/' do |req, res|
    res['Content-Type'] = 'application/json; charset=utf-8'

    if req.path == '/cardano-metrics'
        combined = ""
        ARGV.each { |base_url|
            puts base_url
            url = "#{base_url}/metrics"
            response = Faraday.get(url)
            body = response.body

            combined += body + "\n"
        }

        res.status = 200
        res.body = filterMetrics(combined)
    else
        res.status = 404
        res.body = "Not Found!"
    end
end

trap 'INT' do server.shutdown end

server.start