Milo: Grpc endpoint for multiple builds on a builder

milo/appengine/buildbot/grpc.go

 // Copyright 2016 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 buildbot
 
 import (
         "bytes"
         "compress/gzip"
         "encoding/json"
@@ skipping 35 matching lines @@
 
         bs, err := json.Marshal(b)
         if err != nil {
                 return nil, err
         }
 
         // Marshal the build back into JSON format.
         return &milo.BuildbotBuildJSON{Data: bs}, nil
 }
 
+func (s *Service) GetBuildbotBuildsJSON(

[martiniss, 2016/10/06 21:18:56]

Can you add a basic smoke test or two for this?

[hinoka, 2016/10/07 01:44:54]

Done.

+        c context.Context, req *milo.BuildbotBuildsRequest) (
+        *milo.BuildbotBuildsJSON, error) {
+
+        if req.Master == "" {
+                return nil, grpc.Errorf(codes.InvalidArgument, "No master specified")
+        }
+        if req.Builder == "" {
+                return nil, grpc.Errorf(codes.InvalidArgument, "No builder specified")
+        }
+
+        // Perform an ACL check by fetching the master.
+        _, err := getMasterEntry(c, req.Master)
+        switch {
+        case err == errMasterNotFound:
+                return nil, grpc.Errorf(codes.NotFound, "Master not found")
+        case err != nil:
+                return nil, err
+        }
+
+        limit := req.Limit
+        if limit == 0 {
+                limit = 50

[martiniss, 2016/10/06 21:18:56]

buildbot default limit is 20, why not replicate that?

[hinoka, 2016/10/07 01:44:54]

test-results used 50 i think.  Both are equally arbitrary for me.  20 would be
less strain tho.

+        }
+
+        q := ds.NewQuery("buildbotBuild")
+        q = q.Eq("master", req.Master).
+                Eq("builder", req.Builder).
+                Eq("finished", true).

[martiniss, 2016/10/06 21:18:56]

Do we want to always require finished? Can we make that a parameter?

[hinoka, 2016/10/07 01:44:54]

Done.

+                Limit(limit).
+                Order("-number")
+        builds := []*buildbotBuild{}
+        err = ds.GetAll(c, q, &builds)
+        if err != nil {
+                return nil, err
+        }
+
+        results := make([]*milo.BuildbotBuildJSON, len(builds))
+        for i, b := range builds {
+                // In theory we could do this in parallel, but it doesn't actually go faster
+                // since AppEngine is single-cored.
+                bs, err := json.Marshal(b)
+                if err != nil {
+                        return nil, err
+                }
+                results[i] = &milo.BuildbotBuildJSON{Data: bs}
+        }
+        return &milo.BuildbotBuildsJSON{
+                Builds: results,

[martiniss, 2016/10/06 21:18:56]

Is this going to run into app engine response size constraints like the buildbot
master JSON did?

[hinoka, 2016/10/07 01:44:54]

Unlikely I think.  The main issue we run into usually is the 1MB datastore
limit.  The appengine response limit is 32MB, so theres much more leeway.  Still
possible with a large response size, but CBE has been happily serving responses
of about 50 builds for a while, so I think we're safe.

+        }, nil
+}
+
 // GetCompressedMasterJSON assembles a CompressedMasterJSON object from the
 // provided MasterRequest.
 func (s *Service) GetCompressedMasterJSON(
         c context.Context, req *milo.MasterRequest) (*milo.CompressedMasterJSON, error) {
 
         if req.Name == "" {
                 return nil, grpc.Errorf(codes.InvalidArgument, "No master specified")
         }
 
         entry, err := getMasterEntry(c, req.Name)
@@ skipping 69 matching lines @@
 
         return &milo.CompressedMasterJSON{
                 Internal: entry.Internal,
                 Modified: &google.Timestamp{
                         Seconds: entry.Modified.Unix(),
                         Nanos:   int32(entry.Modified.Nanosecond()),
                 },
                 Data: gzbs.Bytes(),
         }, nil
 }