build_history.rb in codebuild-notifier-1.0.0

- old
+ new
@@ -13,101 +13,116 @@
 # General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with codebuild-notifier.  If not, see <http://www.gnu.org/licenses/>.
 
-require 'active_support'
-require 'active_support/core_ext'
-require 'aws-sdk-dynamodb'
-require 'hashie'
-
 module CodeBuildNotifier
-  class BuildHistory
-    attr_reader :config, :current_build
-
-    delegate :dynamo_table, to: :config
+  class BuildHistory < DynamoBase
     delegate :branch_name, :launched_by_retry?, to: :current_build
 
-    def initialize(config, current_build)
-      @config = config
-      @current_build = current_build
-    end
-
     def last_entry
+      return @last_entry if defined?(@last_entry)
       # If this build was launched using the Retry command from the console
       # or api we don't have a Pull Request or branch name to use in the
       # primary key, so we query by commit hash and project instead.
-      item = launched_by_retry? ? find_by_commit_and_project : find_by_id
+      item = launched_by_retry? ? find_by_commit : find_by_id
 
       # Provide .dot access to hash values from Dynamo item.
-      item && Hashie::Mash.new(item)
+      @last_entry = item && Hashie::Mash.new(item)
     end
 
     def write_entry(source_id)
       updates = hash_to_dynamo_update(new_entry).merge(
-        key: { source_id: source_id }
+        key: { source_id: source_id, version_key: version_key }
       )
 
       yield updates if block_given?
 
-      dynamo_client.update_item(
-        updates.merge(table_name: dynamo_table)
-      )
+      update_item(updates)
+
+      ProjectSummary.new(config, current_build).update
+      BranchEntry.new(config, current_build).update
     end
 
     # The commit hash and project code are used to find which Pull Request
     # or branch the current build belongs to, and the previous build status
     # for that Pull Request or branch.
-    private def find_by_commit_and_project
-      dynamo_client.query(
-        expression_attribute_values: {
-          ':commit_hash' => current_build.commit_hash,
-          ':project_code' => current_build.project_code
-        },
-        filter_expression: 'project_code = :project_code',
+    private def find_by_commit
+      find_latest_version(
+        expression_attribute_values: commit_values,
+        filter_expression: commit_filter,
         index_name: 'commit_hash_index',
-        key_condition_expression: 'commit_hash = :commit_hash',
-        table_name: dynamo_table
-      ).items.first
+        key_condition_expression: 'commit_hash = :commit_hash'
+      )
     end
 
+    # When searching by commit hash, if the current build source version
+    # is for a PR, only return commits with that PR as the source ref.
+    # If source version is not for a pr, only return source refs beginning
+    # with branch/. This helps protect against the edge case where the same
+    # commit appears in two different PRs, or in a PR and whitelisted branch
+    # besides than the PR head.
+    private def commit_values
+      source_ref_val = if current_build.for_pr?
+                         current_build.source_version
+                       else
+                         'branch/'
+                       end
+      {
+        ':commit_hash' => current_build.commit_hash,
+        ':project_code' => current_build.project_code,
+        ':source_ref' => source_ref_val
+      }
+    end
+
+    private def commit_filter
+      source_ref_condition = if current_build.for_pr?
+                               'source_ref = :source_ref'
+                             else
+                               'begins_with(source_ref, :source_ref)'
+                             end
+      "project_code = :project_code AND #{source_ref_condition}"
+    end
+
     private def find_by_id
-      dynamo_client.get_item(
-        key: { 'source_id' => current_build.source_id },
-        table_name: dynamo_table
-      ).item
+      find_latest_version(
+        expression_attribute_values: {
+          ':source_id' => current_build.source_id
+        },
+        key_condition_expression: 'source_id = :source_id'
+      )
     end
 
+    private def find_latest_version(args)
+      dynamo_client.query(
+        args.merge(
+          scan_index_forward: false, # Reverse sort by range key
+          table_name: dynamo_table
+        )
+      ).items.first
+    end
+
     private def new_entry
-      {
-        commit_hash: current_build.commit_hash,
-        project_code: current_build.project_code,
-        status: current_build.status
-      }.tap do |memo|
+      current_build.history_fields.tap do |memo|
         # If launched via manual re-try instead of via a webhook, we don't
         # want to overwrite the current source_ref value that tells us which
         # branch or pull request originally created the dynamo record.
         unless launched_by_retry?
           memo[:source_ref] = current_build.trigger
           memo[:branch_name] = branch_name unless branch_name.empty?
         end
       end
     end
 
-    private def hash_to_dynamo_update(hash)
-      update = hash.each_with_object(
-        expression_attribute_names: {},
-        expression_attribute_values: {},
-        update_expression: []
-      ) do |(key, value), memo|
-        memo[:expression_attribute_names]["##{key}"] = key.to_s
-        memo[:expression_attribute_values][":#{key}"] = value
-        memo[:update_expression] << "##{key} = :#{key}"
+    # The first component of the version_key is the timestamp for the
+    # first build of the current commit hash. The second component
+    # is the timestamp for the current build. This allows easily finding
+    # either the latest commit, or the latest re-build of a commit.
+    private def version_key
+      if launched_by_retry?
+        "#{last_entry.start_time}_#{current_build.start_time}"
+      else
+        "#{current_build.start_time}_#{current_build.start_time}"
       end
-      update.merge(update_expression: "SET #{update[:update_expression].join(', ')}")
-    end
-
-    private def dynamo_client
-      @dynamo_client || Aws::DynamoDB::Client.new(region: config.region)
     end
   end
 end