allow configuring a per-repo concurrency limit via config

Author: svenfuchs

lib/travis/scheduler/config.rb

@@ -10,7 +10,7 @@ class Config < Travis::Config
              enterprise: false,
              github:     { api_url: 'https://api.github.com', source_host: 'github.com' },
              interval:   2,
-             limit:      { default: 5, by_owner: {}, delegate: {} },
+             limit:      { default: 5, by_owner: {}, by_repo: {}, delegate: {} },
              lock:       { strategy: :redis, ttl: 150 },
              logger:     { time_format: false, process_id: false, thread_id: false },
              log_level:  :info,

lib/travis/scheduler/limit/by_repo.rb

@@ -8,7 +8,7 @@ class ByRepo < Struct.new(:context, :owners, :job, :selected, :state, :config)
         include Helper::Context
 
         def enqueue?
-          unlimited? || by_settings
+          by_config || unlimited? || by_setting
         end
 
         def reports
@@ -17,24 +17,34 @@ def reports
 
         private
 
+          def by_config
+            result = current < max_by_config
+            report :repo_config, max_by_config unless result
+            result
+          end
+
           def unlimited?
-            max == 0
+            max_by_setting == 0
           end
 
-          def by_settings
-            result = current < max
-            report :repo_settings, max unless result
+          def by_setting
+            result = current < max_by_setting
+            report :repo_settings, max_by_setting unless result
             result
           end
 
           def current
             state.running_by_repo(repo.id) + selected.select { |j| j.repository_id == repo.id }.size
           end
 
-          def max
+          def max_by_setting
             repo.settings.maximum_number_of_builds.to_i
           end
 
+          def max_by_config
+            config[:limit][:by_repo][repo.slug].to_i
+          end
+
           def repo
             job.repository
           end

spec/travis/scheduler/limit_spec.rb

@@ -91,6 +91,18 @@ def create_jobs(count, attrs = {})
     it { expect(report).to include('user svenfuchs: total: 3, running: 0, queueable: 1') }
   end
 
+  describe 'with a default limit 5 and a repo keychain/config limit 2' do
+    before { config.limit.default = 5 }
+    before { config.limit.by_repo = { repo.slug => 2 } }
+    before { create_jobs(3) }
+    before { repo.settings.update_attributes!(maximum_number_of_builds: 2) }
+    before { subject }
+
+    it { expect(subject.size).to eq 2 }
+    it { expect(report).to include('max jobs for repo svenfuchs/gem-release by repo_settings: 2') }
+    it { expect(report).to include('user svenfuchs: total: 3, running: 0, queueable: 2') }
+  end
+
   describe 'with a default limit 5 and a repo settings limit 2' do
     before { config.limit.default = 5 }
     before { create_jobs(3) }