[milo] Refactor all html knowledge out of backends.

milo/buildsource/buildbot/buildinfo.go

 // Copyright 2017 The LUCI Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //      http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 11 matching lines @@
 
         "github.com/luci/luci-go/common/data/stringset"
         "github.com/luci/luci-go/common/logging"
         miloProto "github.com/luci/luci-go/common/proto/milo"
         "github.com/luci/luci-go/grpc/grpcutil"
         "github.com/luci/luci-go/logdog/client/coordinator"
         "github.com/luci/luci-go/logdog/common/types"
         "github.com/luci/luci-go/luci_config/common/cfgtypes"
         milo "github.com/luci/luci-go/milo/api/proto"
         "github.com/luci/luci-go/milo/buildsource/rawpresentation"
+        "github.com/luci/luci-go/milo/common"
 
         "google.golang.org/grpc/codes"
 
         "golang.org/x/net/context"
 )
 
 // BuildInfoProvider is a configuration that provides build information.
 //
 // In a production system, this will be completely defaults. For testing, the
 // various services and data sources may be substituted for testing stubs.
@@ skipping 23 matching lines @@
 //      3) Fetches the LogDog annotation stream and resolves it into a Step.
 //      4) Merges some operational BuildBot build information into the Step.
 func (p *BuildInfoProvider) GetBuildInfo(c context.Context, req *milo.BuildInfoRequest_BuildBot,
         projectHint cfgtypes.ProjectName) (*milo.BuildInfoResponse, error) {
 
         logging.Infof(c, "Loading build info for master %q, builder %q, build #%d",
                 req.MasterName, req.BuilderName, req.BuildNumber)
 
         // Load the BuildBot build from datastore.
         build, err := getBuild(c, req.MasterName, req.BuilderName, int(req.BuildNumber))
-        switch err {
-        case errBuildNotFound:
-                return nil, grpcutil.Errf(codes.NotFound, "Build #%d for master %q, builder %q was not found",
-                        req.BuildNumber, req.MasterName, req.BuilderName)
-        case errNotAuth:
-                return nil, grpcutil.Unauthenticated
-        case nil:
-                // continue
-        default:
-                logging.WithError(err).Errorf(c, "Failed to load build info.")
-                return nil, grpcutil.Internal
+        if err != nil {
+                switch common.ErrorTag.In(err) {
+                case common.CodeNotFound:
+                        return nil, grpcutil.Errf(codes.NotFound, "Build #%d for master %q, builder %q was not found",
+                                req.BuildNumber, req.MasterName, req.BuilderName)
+
+                case common.CodeUnauthorized:
+                        return nil, grpcutil.Unauthenticated
+
+                default:
+                        logging.WithError(err).Errorf(c, "Failed to load build info.")
+                        return nil, grpcutil.Internal
+                }
         }
 
         // Create a new LogDog client.
         client, err := p.newLogdogClient(c)
         if err != nil {
                 logging.WithError(err).Errorf(c, "Failed to create LogDog client.")
                 return nil, grpcutil.Internal
         }
 
         // Identify the LogDog annotation stream from the build.
@@ skipping 178 matching lines @@
                 allProps.Add(prop.Name)
 
                 step.Property = append(step.Property, &miloProto.Step_Property{
                         Name:  prop.Name,
                         Value: fmt.Sprintf("%v", prop.Value),
                 })
         }
 
         return nil
 }