Milo: Add LogDog annotation stream support.

appengine/cmd/milo/logdog/http.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 logdog
+
+import (
+        "net/http"
+        "strings"
+        "sync"
+
+        "github.com/julienschmidt/httprouter"
+        "github.com/luci/luci-go/appengine/cmd/milo/miloerror"
+        "github.com/luci/luci-go/appengine/cmd/milo/settings"
+        authClient "github.com/luci/luci-go/appengine/gaeauth/client"
+        "github.com/luci/luci-go/common/config"
+        log "github.com/luci/luci-go/common/logging"
+        "github.com/luci/luci-go/logdog/common/types"
+        "github.com/luci/luci-go/server/templates"
+
+        "golang.org/x/net/context"
+)
+
+// AnnotationStream is a ThemedHandler that renders a LogDog Milo annotation
+// protobuf stream.
+//
+// The protobuf stream is fetched live from LogDog and cached locally, either
+// temporarily (if incomplete) or indefinitely (if complete).
+type AnnotationStream struct {
+        // logDogClient is a reusable HTTP client to use for LogDog.
+        logDogClient *http.Client
+
+        initMu sync.Mutex
+}
+
+// init initializes the process-global state of the AnnotationStream.
+func (s *AnnotationStream) init(c context.Context) *miloerror.Error {
+        s.initMu.Lock()

[nodir, 2016/07/29 23:00:32]

insert a s.logdogClient!=nil check with read-lock held. if it is nil, do the
rest

[dnj, 2016/07/29 23:24:43]

Done.

+        defer s.initMu.Unlock()
+
+        if s.logDogClient != nil {
+                return nil
+        }
+
+        // Initialize the LogDog client.
+        a, err := authClient.Transport(c, nil, nil)
+        if err != nil {
+                log.WithError(err).Errorf(c, "Failed to get transport for LogDog server.")
+                return &miloerror.Error{
+                        Code: http.StatusInternalServerError,
+                }
+        }
+
+        s.logDogClient = &http.Client{
+                Transport: a,
+        }
+        return nil
+}
+
+// GetTemplateName implements settings.ThemedHandler.
+func (s *AnnotationStream) GetTemplateName(t settings.Theme) string {
+        return "build.html"
+}
+
+// Render implements settings.ThemedHandler.
+func (s *AnnotationStream) Render(c context.Context, req *http.Request, p httprouter.Params) (*templates.Args, error) {
+        if err := s.init(c); err != nil {
+                return nil, err
+        }
+
+        as := annotationStreamRequest{
+                AnnotationStream: s,
+
+                project: config.ProjectName(p.ByName("project")),
+                path:    types.StreamPath(strings.Trim(p.ByName("path"), "/")),
+                host:    req.FormValue("host"),
+        }
+        if err := as.normalize(); err != nil {
+                return nil, err
+        }
+
+        // Load the Milo annotation protobuf from the annotation stream.
+        if err := as.load(c); err != nil {
+                return nil, err
+        }
+
+        // Convert the Milo Annotation protobuf to Milo objects.
+        return &templates.Args{
+                "Build": as.toMiloBuild(c),
+        }, nil
+}