Merge branch 'fix/ci-builds-exception' into 'master'

Return a correct result structure in case of an exception in CiBuildsCollector#get_builds

See merge request !50

Gemfile.lock

 PATH
   remote: .
   specs:
-    gitlab-monitor (1.5.0)
+    gitlab-monitor (1.6.0)
       pg (~> 0.18.4)
       quantile (~> 0.2.0)
       redis-namespace (~> 1.5.2)

lib/gitlab_monitor/database/ci_builds.rb

@@ -103,7 +103,7 @@ module GitLab
           results
         rescue PG::UndefinedTable, PG::UndefinedColumn
-          {}
+          results
         end
       end

lib/gitlab_monitor/version.rb

 module GitLab
   module Monitor
-    VERSION = "1.5.0".freeze
+    VERSION = "1.6.0".freeze
   end
 end

spec/database/ci_builds_spec.rb

@@ -71,25 +71,48 @@ describe GitLab::Monitor::Database do
       allow_any_instance_of(GitLab::Monitor::Database::CiBuildsCollector).to receive(:connected?).and_return(true)
     end
-    it "responds with Prometheus metrics" do
-      prober.probe_db
-      prober.write_to(writer)
-      output = <<-OUTPUT
-        ci_pending_builds{namespace="1",shared_runners="yes"} 30
-        ci_pending_builds{namespace="2",shared_runners="yes"} 50
-        ci_pending_builds{namespace="",shared_runners="yes"} 3
-        ci_pending_builds{namespace="",shared_runners="no"} 0
-        ci_created_builds{namespace="1",shared_runners="no"} 10
-        ci_created_builds{namespace="2",shared_runners="no"} 20
-        ci_created_builds{namespace="",shared_runners="yes"} 0
-        ci_created_builds{namespace="",shared_runners="no"} 0
-        ci_stale_builds 2
-        ci_running_builds{runner="1",shared_runner="yes",mirror="no",pending_delete="no",mirror_trigger_builds="no"} 15
-        ci_running_builds{runner="2",shared_runner="no",mirror="yes",pending_delete="no",mirror_trigger_builds="yes"} 5
+    context "when no PG exceptions are raised" do
+      it "responds with Prometheus metrics" do
+        prober.probe_db
+        prober.write_to(writer)
+        output = <<-OUTPUT
+          ci_pending_builds{namespace="1",shared_runners="yes"} 30
+          ci_pending_builds{namespace="2",shared_runners="yes"} 50
+          ci_pending_builds{namespace="",shared_runners="yes"} 3
+          ci_pending_builds{namespace="",shared_runners="no"} 0
+          ci_created_builds{namespace="1",shared_runners="no"} 10
+          ci_created_builds{namespace="2",shared_runners="no"} 20
+          ci_created_builds{namespace="",shared_runners="yes"} 0
+          ci_created_builds{namespace="",shared_runners="no"} 0
+          ci_stale_builds 2
+          ci_running_builds{runner="1",shared_runner="yes",mirror="no",pending_delete="no",mirror_trigger_builds="no"} 15
+          ci_running_builds{runner="2",shared_runner="no",mirror="yes",pending_delete="no",mirror_trigger_builds="yes"} 5
         OUTPUT
-      expect(writer.string).to eq(output.gsub(/^ {8}/, ""))
+        expect(writer.string).to eq(output.strip_heredoc)
+      end
+    end
+
+    context "when PG exceptions are raised" do
+      before do
+        allow(connection).to receive(:exec).and_raise(PG::UndefinedColumn)
+      end
+
+      it "responds with Prometheus metrics" do
+        prober.probe_db
+        prober.write_to(writer)
+
+        output = <<-OUTPUT
+          ci_pending_builds{namespace="",shared_runners="yes"} 0
+          ci_pending_builds{namespace="",shared_runners="no"} 0
+          ci_created_builds{namespace="",shared_runners="yes"} 0
+          ci_created_builds{namespace="",shared_runners="no"} 0
+          ci_stale_builds 0
+        OUTPUT
+
+        expect(writer.string).to eq(output.strip_heredoc)
+      end
     end
   end
 end

spec/spec_helper.rb

@@ -4,6 +4,9 @@ require "gitlab_monitor"
 require "open3"
 require "tmpdir"
+$LOAD_PATH.unshift File.expand_path(".")
+Dir["spec/support/**/*.rb"].each do |f| require f end
+
 class GitRepoBuilder
   def origin
     @origin ||= create_origin

spec/support/string.rb

+class String
+  # Copied from activesupport gem
+  def strip_heredoc
+    gsub(/^#{scan(/^[ \t]*(?=\S)/).min}/, "".freeze)
+  end
+end