Rescue from network errors when querying Prometheus in the background

lib/gitlab/prometheus/queries/validate_query.rb

@@ -7,7 +7,7 @@ module Gitlab
         def query(query)
           client_query(query)
           { valid: true }
-        rescue Gitlab::PrometheusClient::QueryError, Gitlab::HTTP::BlockedUrlError => ex
+        rescue Gitlab::PrometheusClient::QueryError, Gitlab::PrometheusClient::ConnectionError => ex
           { valid: false, error: ex.message }
         end
 

lib/gitlab/prometheus_client.rb

@@ -151,12 +151,8 @@ module Gitlab
 
     def get(path, args)
       Gitlab::HTTP.get(path, { query: args }.merge(http_options) )
-    rescue SocketError
-      raise PrometheusClient::ConnectionError, "Can't connect to #{api_url}"
-    rescue OpenSSL::SSL::SSLError
-      raise PrometheusClient::ConnectionError, "#{api_url} contains invalid SSL data"
-    rescue Errno::ECONNREFUSED
-      raise PrometheusClient::ConnectionError, 'Connection refused'
+    rescue *Gitlab::HTTP::HTTP_ERRORS => e
+      raise PrometheusClient::ConnectionError, e.message
     end
 
     def handle_management_api_response(response)

spec/lib/gitlab/prometheus_client_spec.rb

@@ -107,36 +107,14 @@ RSpec.describe Gitlab::PrometheusClient do
     let(:prometheus_url) {"https://prometheus.invalid.example.com/api/v1/query?query=1"}
 
     shared_examples 'exceptions are raised' do
-      it 'raises a Gitlab::PrometheusClient::ConnectionError error when a SocketError is rescued' do
-        req_stub = stub_prometheus_request_with_exception(prometheus_url, SocketError)
+      Gitlab::HTTP::HTTP_ERRORS.each do |error|
+        it "raises a Gitlab::PrometheusClient::ConnectionError when a #{error} is rescued" do
+          req_stub = stub_prometheus_request_with_exception(prometheus_url, error.new)
 
-        expect { subject }
-          .to raise_error(Gitlab::PrometheusClient::ConnectionError, "Can't connect to #{prometheus_url}")
-        expect(req_stub).to have_been_requested
-      end
-
-      it 'raises a Gitlab::PrometheusClient::ConnectionError error when a SSLError is rescued' do
-        req_stub = stub_prometheus_request_with_exception(prometheus_url, OpenSSL::SSL::SSLError)
-
-        expect { subject }
-          .to raise_error(Gitlab::PrometheusClient::ConnectionError, "#{prometheus_url} contains invalid SSL data")
-        expect(req_stub).to have_been_requested
-      end
-
-      it 'raises a Gitlab::PrometheusClient::ConnectionError error when a Gitlab::HTTP::ResponseError is rescued' do
-        req_stub = stub_prometheus_request_with_exception(prometheus_url, Gitlab::HTTP::ResponseError)
-
-        expect { subject }
-          .to raise_error(Gitlab::PrometheusClient::ConnectionError, "Network connection error")
-        expect(req_stub).to have_been_requested
-      end
-
-      it 'raises a Gitlab::PrometheusClient::ConnectionError error when a Gitlab::HTTP::ResponseError with a code is rescued' do
-        req_stub = stub_prometheus_request_with_exception(prometheus_url, Gitlab::HTTP::ResponseError.new(code: 400))
-
-        expect { subject }
-          .to raise_error(Gitlab::PrometheusClient::ConnectionError, "Network connection error")
-        expect(req_stub).to have_been_requested
+          expect { subject }
+            .to raise_error(Gitlab::PrometheusClient::ConnectionError, kind_of(String))
+          expect(req_stub).to have_been_requested
+        end
       end
     end
 

spec/models/concerns/prometheus_adapter_spec.rb

@@ -165,6 +165,14 @@ RSpec.describe PrometheusAdapter, :use_clean_rails_memory_store_caching do
         it { is_expected.to eq(success: false, result: %(#{status} - "QUERY FAILED!")) }
       end
     end
+
+    context "when client raises Gitlab::PrometheusClient::ConnectionError" do
+      before do
+        stub_any_prometheus_request.to_raise(Gitlab::PrometheusClient::ConnectionError)
+      end
+
+      it { is_expected.to include(success: false, result: kind_of(String)) }
+    end
   end
 
   describe '#build_query_args' do