[milo] Add BuildSummary and common models.

milo/appengine/common/model/build_summary.go

Index: milo/appengine/common/model/build_summary.go
diff --git a/milo/appengine/common/model/build_summary.go b/milo/appengine/common/model/build_summary.go
new file mode 100644
index 0000000000000000000000000000000000000000..849686acbeb24bf47de6fedf2fefed5183d428a2
--- /dev/null
+++ b/milo/appengine/common/model/build_summary.go
@@ -0,0 +1,87 @@
+// Copyright 2017 The LUCI Authors. All rights reserved.
+// Use of this source code is governed under the Apache License, Version 2.0
+// that can be found in the LICENSE file.
+
+package model
+
+import (
+	"time"
+
+	"github.com/luci/gae/service/datastore"
+)
+
+// BuildSummary is a datastore model which is used for storing staandardized
+// summarized build data, and is used for backend-agnostic views (i.e. builders,
+// console). It contains only data that:
+//   * is necessary to render these simplified views
+//   * is present in all implementations (buildbot, buildbucket)
+//
+// This entity will live as a child of the various implementation's
+// representations of a build (e.g. buildbotBuild). It has various 'tag' fields
+// so that it can be queried by the various backend-agnostic views.
+type BuildSummary struct {
+	// _id for a BuildSummary is always 1
+	_ int64 `gae:"$id,1"`
+
+	// BuildKey will always point to the "real" build, i.e. a buildbotBuild or
+	// a buildbucketBuild. It is always the parent key for the BuildSummary.
+	BuildKey *datastore.Key `gae:"$parent"`
+
+	// Global identifier for the builder that this Build belongs to, i.e.:
+	//   "buildbot/<mastername>/<buildername>"
+	//   "buildbucket/<bucketname>/<buildername>"
+	BuilderID string
+
+	// KnownConsoleHash is used for backfilling and must always equal the raw
+	// value of:
+	//
+	//   sha256(sorted(ConsoleEpochs.keys())
+	//
+	// This is used to identify BuildSummaries which haven't yet been included in
+	// some new Console definition (or which have been removed from a Console
+	// definition).
+	KnownConsoleHash []byte
+
+	// ConsoleEpochs is used for backfilling, and is a series of cmpbin tuples:
+	//
+	//   (console_name[str], recorded_epoch[int])
+	//
+	// This maps which epoch (version) of a console definition this BuildSummary
+	// belongs to. Whenever a console definition changes, its epoch increases. The
+	// backfiller will then identify BuildSummary objects which are out of date
+	// and update them.
+	ConsoleEpochs [][]byte
+
+	// ConsoleTags contains query tags for the console view. These are cmpbin
+	// tuples which look like:
+	//
+	//   (console_name[str], sort_criteria[tuple], sort_values[tuple])
+	//
+	// `sort_criteria` are defined by the console definition, and will likely look
+	// like (manifest_name[str], repo_url[str]), but other sort_criteria may be
+	// added later.
+	//
+	// `sort_values` are defined by the selected sort_criteria, and will likely
+	// look like (commit_revision[str],). In any event, this string is opaque and
+	// only to be used by the console itself.
+	ConsoleTags [][]byte
+
+	// Created is the time when the Build was first created. Due to pending
+	// queues, this may be substantially before Summary.Start.
+	Created time.Time
+
+	// Summary summarizes relevant bits about the overall build.
+	Summary Summary
+
+	// CurrentStep summarizes relevant bits about the currently running step (if
+	// any). Only expected to be set if !Summary.Status.Terminal().
+	CurrentStep Summary
+
+	// Manifests is a list of links to source manifests that this build reported.
+	Manifests []ManifestLink
+
+	// Patches is the list of patches which are associated with this build.
+	// We reserve the multi-patch case for advanced (multi-repo) tryjobs...
+	// Typically there will only be one patch associated with a build.
+	Patches []PatchInfo
+}