[milo] Refactor all html knowledge out of backends.

milo/buildsource/swarming/html.go

Index: milo/buildsource/swarming/html.go
diff --git a/milo/buildsource/swarming/html.go b/milo/buildsource/swarming/html.go
deleted file mode 100644
index 8f778071f317ac7c09910d3d4494b47480eb5c0d..0000000000000000000000000000000000000000
--- a/milo/buildsource/swarming/html.go
+++ /dev/null
@@ -1,155 +0,0 @@
-// Copyright 2015 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,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package swarming
-
-import (
-	"errors"
-	"fmt"
-	"net/http"
-	"os"
-
-	"golang.org/x/net/context"
-	"google.golang.org/api/googleapi"
-
-	"github.com/luci/luci-go/common/logging"
-	"github.com/luci/luci-go/milo/common"
-	"github.com/luci/luci-go/server/router"
-	"github.com/luci/luci-go/server/templates"
-)
-
-var errUnrecognizedHost = errors.New("Unregistered Swarming Host")
-
-// getSwarmingHost parses the swarming hostname out of the context.  If
-// none is specified, get the default swarming host out of the global
-// configs.
-func getSwarmingHost(c context.Context, r *http.Request) (string, error) {
-	settings := common.GetSettings(c)
-	if settings.Swarming == nil {
-		err := errors.New("swarming not in settings")
-		logging.Errorf(c, err.Error())
-		return "", err
-	}
-	server := r.FormValue("server")
-	// If server isn't specified, return the default host.
-	if server == "" || server == settings.Swarming.DefaultHost {
-		return settings.Swarming.DefaultHost, nil
-	}
-	// If it is specified, validate the hostname.
-	for _, hostname := range settings.Swarming.AllowedHosts {
-		if server == hostname {
-			return server, nil
-		}
-	}
-	return "", errUnrecognizedHost
-}
-
-// Build is for deciphering recipe builds from swarming based off of logs.
-type Build struct {
-	// bl is the buildLoader to use. A zero value is suitable for production, but
-	// this can be overridden for testing.
-	bl BuildLoader
-}
-
-// LogHandler writes the build log to the given response writer.
-func LogHandler(c *router.Context) {
-	id := c.Params.ByName("id")
-	if id == "" {
-		common.ErrorPage(c, http.StatusBadRequest, "no id")
-		return
-	}
-	logname := c.Params.ByName("logname")
-	if logname == "" {
-		common.ErrorPage(c, http.StatusBadRequest, "no log name")
-		return
-	}
-
-	hostname, err := getSwarmingHost(c.Context, c.Request)
-	if err != nil {
-		common.ErrorPage(c, http.StatusBadRequest,
-			fmt.Sprintf("no swarming host: %s", err.Error()))
-		return
-	}
-	sf, err := NewProdService(c.Context, hostname)
-	if err != nil {
-		common.ErrorPage(c, errCode(err), err.Error())
-		return
-	}
-
-	log, closed, err := swarmingBuildLogImpl(c.Context, sf, id, logname)
-	if err != nil {
-		common.ErrorPage(c, errCode(err), err.Error())
-		return
-	}
-
-	templates.MustRender(c.Context, c.Writer, "pages/log.html", templates.Args{
-		"Log":    log,
-		"Closed": closed,
-	})
-}
-
-func BuildHandler(c *router.Context) {
-	(Build{}).Render(c)
-}
-
-// Render renders both the build page and the log.
-func (b Build) Render(c *router.Context) {
-	// Get the swarming ID
-	id := c.Params.ByName("id")
-	if id == "" {
-		common.ErrorPage(c, http.StatusBadRequest, "no id")
-		return
-	}
-
-	hostname, err := getSwarmingHost(c.Context, c.Request)
-	if err != nil {
-		common.ErrorPage(c, http.StatusBadRequest,
-			fmt.Sprintf("no swarming host: %s", err.Error()))
-		return
-	}
-	sf, err := NewProdService(c.Context, hostname)
-	if err != nil {
-		common.ErrorPage(c, errCode(err), err.Error())
-		return
-	}
-
-	result, err := b.bl.SwarmingBuildImpl(c.Context, sf, id)
-	if err != nil {
-		common.ErrorPage(c, errCode(err), err.Error())
-		return
-	}
-
-	templates.MustRender(c.Context, c.Writer, "pages/build.html", templates.Args{
-		"Build": result,
-	})
-}
-
-// errCode resolves recognized errors into proper http response codes.
-func errCode(err error) int {
-	if err == errUnrecognizedHost {
-		return http.StatusBadRequest
-	}
-	if isAPINotFound(err) || os.IsNotExist(err) {
-		return http.StatusNotFound
-	}
-	return http.StatusInternalServerError
-}
-
-// isAPINotFound returns true if err is a HTTP 404 API response.
-func isAPINotFound(err error) bool {
-	if apiErr, ok := err.(*googleapi.Error); ok && apiErr.Code == http.StatusNotFound {
-		return true
-	}
-	return false
-}