1 files changed, 36 insertions, 30 deletions
diff --git a/lib/gitlab/prometheus_client.rb b/lib/gitlab/prometheus_client.rb
index aa94614bf18..659021c9ac9 100644
--- a/lib/gitlab/prometheus_client.rb
+++ b/lib/gitlab/prometheus_client.rb
@@ -1,12 +1,13 @@
 module Gitlab
-  PrometheusError = Class.new(StandardError)
-
   # Helper methods to interact with Prometheus network services & resources
   class PrometheusClient
-    attr_reader :api_url
+    Error = Class.new(StandardError)
+    QueryError = Class.new(Gitlab::PrometheusClient::Error)
+
+    attr_reader :rest_client, :headers
 
-    def initialize(api_url:)
-      @api_url = api_url
+    def initialize(rest_client)
+      @rest_client = rest_client
     end
 
     def ping
@@ -22,10 +23,10 @@ module Gitlab
     def query_range(query, start: 8.hours.ago, stop: Time.now)
       get_result('matrix') do
         json_api_get('query_range',
-          query: query,
-          start: start.to_f,
-          end: stop.to_f,
-          step: 1.minute.to_i)
+                     query: query,
+                     start: start.to_f,
+                     end: stop.to_f,
+                     step: 1.minute.to_i)
       end
     end
 
@@ -40,39 +41,44 @@ module Gitlab
     private
 
     def json_api_get(type, args = {})
-      get(join_api_url(type, args))
+      path = ['api', 'v1', type].join('/')
+      get(path, args)
+    rescue JSON::ParserError
+      raise PrometheusClient::Error, 'Parsing response failed'
     rescue Errno::ECONNREFUSED
-      raise PrometheusError, 'Connection refused'
-    end
-
-    def join_api_url(type, args = {})
-      url = URI.parse(api_url)
-    rescue URI::Error
-      raise PrometheusError, "Invalid API URL: #{api_url}"
-    else
-      url.path = [url.path.sub(%r{/+\z}, ''), 'api', 'v1', type].join('/')
-      url.query = args.to_query
-
-      url.to_s
+      raise PrometheusClient::Error, 'Connection refused'
     end
 
-    def get(url)
-      handle_response(HTTParty.get(url))
+    def get(path, args)
+      response = rest_client[path].get(params: args)
+      handle_response(response)
     rescue SocketError
-      raise PrometheusError, "Can't connect to #{url}"
+      raise PrometheusClient::Error, "Can't connect to #{rest_client.url}"
     rescue OpenSSL::SSL::SSLError
-      raise PrometheusError, "#{url} contains invalid SSL data"
-    rescue HTTParty::Error
-      raise PrometheusError, "Network connection error"
+      raise PrometheusClient::Error, "#{rest_client.url} contains invalid SSL data"
+    rescue RestClient::ExceptionWithResponse => ex
+      handle_exception_response(ex.response)
+    rescue RestClient::Exception
+      raise PrometheusClient::Error, "Network connection error"
     end
 
     def handle_response(response)
+      json_data = JSON.parse(response.body)
+      if response.code == 200 && json_data['status'] == 'success'
+        json_data['data'] || {}
+      else
+        raise PrometheusClient::Error, "#{response.code} - #{response.body}"
+      end
+    end
+
+    def handle_exception_response(response)
       if response.code == 200 && response['status'] == 'success'
         response['data'] || {}
       elsif response.code == 400
-        raise PrometheusError, response['error'] || 'Bad data received'
+        json_data = JSON.parse(response.body)
+        raise PrometheusClient::QueryError, json_data['error'] || 'Bad data received'
       else
-        raise PrometheusError, "#{response.code} - #{response.body}"
+        raise PrometheusClient::Error, "#{response.code} - #{response.body}"
       end
     end