milo: buildbucket builer view

appengine/cmd/milo/buildbucket/builder.go

Index: appengine/cmd/milo/buildbucket/builder.go
diff --git a/appengine/cmd/milo/buildbucket/builder.go b/appengine/cmd/milo/buildbucket/builder.go
new file mode 100644
index 0000000000000000000000000000000000000000..260a5b1d16e704a82a621dd410c56b444345472e
--- /dev/null
+++ b/appengine/cmd/milo/buildbucket/builder.go
@@ -0,0 +1,290 @@
+// 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 buildbucket
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/url"
+	"os"
+	"path"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+
+	"golang.org/x/net/context"
+	"google.golang.org/api/googleapi"
+
+	"github.com/luci/luci-go/appengine/cmd/milo/resp"
+	"github.com/luci/luci-go/common/api/buildbucket/buildbucket/v1"
+	"github.com/luci/luci-go/common/clock"
+	"github.com/luci/luci-go/common/errors"
+	"github.com/luci/luci-go/common/logging"

[hinoka, 2016/07/08 23:26:05]

Rest of milo uses.  log "github.com/luci/..../logging"

Not sure why, I think Dan just likes it that way.  Might as well keep it for
consistency.

[nodir, 2016/07/09 00:00:49]

Done.

+	"github.com/luci/luci-go/common/parallel"
+	"github.com/luci/luci-go/common/retry"
+)
+
+// search executes the search request with retries and exponential back-off.
+func search(c context.Context, client *buildbucket.Service, req *buildbucket.SearchCall) (
+	*buildbucket.ApiSearchResponseMessage, error) {
+
+	var res *buildbucket.ApiSearchResponseMessage
+	err := retry.Retry(
+		c,
+		retry.TransientOnly(retry.Default),
+		func() error {
+			var err error
+			res, err = req.Do()
+			if apiErr, ok := err.(*googleapi.Error); ok && apiErr.Code >= 500 {
+				err = errors.WrapTransient(apiErr)
+			}
+			return err
+		},
+		func(err error, wait time.Duration) {
+			logging.WithError(err).Warningf(c, "buildbucket search request failed transiently, will retry in %s", wait)
+		})
+	return res, err
+}
+
+// fetchBuilds fetches builds given a criteria.
+// The returned builds are sorted by build creation descending.
+// count defines maximum number of builds to fetch, defaults to 100.
+func fetchBuilds(c context.Context, client *buildbucket.Service, bucket, builder,
+	status string, count int) ([]*buildbucket.ApiBuildMessage, error) {
+
+	req := client.Search()
+	req.Bucket(bucket)
+	req.Status(status)
+	req.Tag("builder:" + builder)
+
+	if count <= 0 {
+		count = 100
+	}
+
+	fetched := make([]*buildbucket.ApiBuildMessage, 0, count)
+	start := clock.Now(c)
+	for len(fetched) < count {
+		req.MaxBuilds(int64(count - len(fetched)))
+
+		res, err := search(c, client, req)
+		switch {
+		case err != nil:
+			return fetched, err
+		case res.Error != nil:
+			return fetched, fmt.Errorf(res.Error.Message)
+		}
+
+		fetched = append(fetched, res.Builds...)
+
+		if len(res.Builds) == 0 || res.NextCursor == "" {
+			break
+		}
+		req.StartCursor(res.NextCursor)
+	}
+	logging.Debugf(c, "Fetched %d %s builds in %s", len(fetched), status, clock.Since(c, start))
+	return fetched, nil
+}
+
+// toMiloBuild converts a buildbucket build to a milo build.
+// The probability of returning an error if very low.
+func toMiloBuild(c context.Context, build *buildbucket.ApiBuildMessage) (*resp.BuildSummary, error) {
+	// Parsing of parameters and result details is best effort.
+	var params buildParameters
+	if err := json.NewDecoder(strings.NewReader(build.ParametersJson)).Decode(&params); err != nil {
+		logging.Errorf(c, "Could not parse parameters of build %d: %s", build.Id, err)
+	}
+	var resultDetails resultDetails
+	if err := json.NewDecoder(strings.NewReader(build.ResultDetailsJson)).Decode(&resultDetails); err != nil {
+		logging.Errorf(c, "Could not parse result details of build %d: %s", build.Id, err)
+	}
+
+	result := &resp.BuildSummary{
+		Text:     []string{fmt.Sprintf("buildbucket id %d", build.Id)},
+		Revision: resultDetails.Properties.GotRevision,
+	}
+	if result.Revision == "" {
+		result.Revision = params.Properties.Revision
+	}
+
+	var err error
+	result.Status, err = parseStatus(build)
+	if err != nil {
+		// almost never happens
+		return nil, err
+	}
+
+	result.PendingTime.Started = parseTimestamp(build.CreatedTs)
+	switch build.Status {
+	case "SCHEDULED":
+		result.PendingTime.Duration = clock.Since(c, result.PendingTime.Started)
+
+	case "STARTED":

[hinoka, 2016/07/08 23:26:05]

You can set pending interval here too (might be useful for display next to
builds saying it waiting this long, and took this long to run, etc)

Unless, this data isn't available.

[nodir, 2016/07/09 00:00:49]

good point, done

+		result.ExecutionTime.Started = parseTimestamp(build.StatusChangedTs)
+		result.ExecutionTime.Duration = clock.Since(c, result.PendingTime.Started)
+
+	case "COMPLETED":

[hinoka, 2016/07/08 23:26:05]

No started time?

[nodir, 2016/07/09 00:00:49]

unfortunately buildbucket does not provide it; updated comment

+		// we don't have execution duration.
+		result.ExecutionTime.Finished = parseTimestamp(build.CompletedTs)
+	}
+
+	cl := getChangeList(build, &params, &resultDetails)
+	if cl != nil {
+		result.Blame = []*resp.Commit{cl}
+	}
+
+	tags := ParseTags(build.Tags)
+
+	if build.Url != "" {
+		u := build.Url
+		parsed, err := url.Parse(u)
+
+		// map milo links to itself
+		switch {
+		case err != nil:
+			logging.Errorf(c, "invalid URL in build %d: %s", build.Id, err)
+		case parsed.Host == "luci-milo.appspot.com":
+			parsed.Host = ""
+			parsed.Scheme = ""
+			u = parsed.String()
+		}
+
+		result.Link = &resp.Link{
+			URL:   u,
+			Label: strconv.FormatInt(build.Id, 10),
+		}
+
+		// compute the best link label
+		if taskID := tags["swarming_task_id"]; taskID != "" {
+			result.Link.Label = taskID
+		} else if resultDetails.Properties.BuildNumber != 0 {
+			result.Link.Label = strconv.Itoa(resultDetails.Properties.BuildNumber)
+		} else if parsed != nil {
+			// does the URL look like a buildbot build URL?
+			pattern := fmt.Sprintf(
+				`/%s/builders/%s/builds/`,
+				strings.TrimPrefix(build.Bucket, "master."), params.BuilderName)
+			beforeBuildNumber, buildNumberStr := path.Split(parsed.Path)
+			_, err := strconv.Atoi(buildNumberStr)
+			if strings.HasSuffix(beforeBuildNumber, pattern) && err == nil {
+				result.Link.Label = buildNumberStr
+			}
+		}
+	}
+
+	return result, nil
+}
+
+func getDebugBuilds(c context.Context, bucket, builder string, maxCompletedBuilds int, target *resp.Builder) error {
+	resFile, err := os.Open(filepath.Join("testdata", "buildbucket", bucket, builder+".json"))
+	if err != nil {
+		return err
+	}
+	defer resFile.Close()
+
+	res := &buildbucket.ApiSearchResponseMessage{}
+	if err := json.NewDecoder(resFile).Decode(res); err != nil {
+		return err
+	}
+
+	for _, bb := range res.Builds {
+		mb, err := toMiloBuild(c, bb)
+		if err != nil {
+			// this is debugging, so it is fine to stop on first error.
+			return err
+		}
+		switch mb.Status {
+		case resp.NotRun:
+			target.PendingBuilds = append(target.PendingBuilds, mb)
+
+		case resp.Running:
+			target.CurrentBuilds = append(target.CurrentBuilds, mb)
+
+		case resp.Success, resp.Failure, resp.InfraFailure, resp.Warning:
+			if len(target.FinishedBuilds) < maxCompletedBuilds {
+				target.FinishedBuilds = append(target.FinishedBuilds, mb)
+			}
+
+		default:
+			panic("impossible")
+		}
+	}
+	return nil
+}
+
+// builderImpl is the implementation for getting a milo builder page from buildbucket.
+func builderImpl(c context.Context, server, bucket, builder string, maxCompletedBuilds int) (*resp.Builder, error) {
+	if maxCompletedBuilds <= 0 {
+		maxCompletedBuilds = 20
+	}
+
+	result := &resp.Builder{
+		Name: builder,
+	}
+	if server == "debug" {
+		if err := getDebugBuilds(c, bucket, builder, maxCompletedBuilds, result); err != nil {

[hinoka, 2016/07/08 23:26:05]

err := getDebugBuilds(...)
return result, err

And then you don't need the else

[nodir, 2016/07/09 00:00:49]

Done.

+			return result, err
+		}
+	} else {
+		client, err := newClient(c, server)
+		if err != nil {
+			return nil, err
+		}
+
+		fetch := func(target *[]*resp.BuildSummary, status string, count int) error {
+			builds, err := fetchBuilds(c, client, bucket, builder, status, count)
+			if err != nil {
+				logging.Errorf(c, "Could not fetch builds with status %s: %s", status, err)
+				return err
+			}
+			*target = make([]*resp.BuildSummary, 0, len(builds))
+			for _, bb := range builds {
+				mb, err := toMiloBuild(c, bb)
+				if err != nil {

[hinoka, 2016/07/08 23:26:05]

Suggestion: Add a placeholder build, with status infrafailure, with step text
indicating the failure (or "see logs").

[nodir, 2016/07/09 00:00:49]

good idea, done

+					logging.Errorf(c, "Invalid build %d: %s", bb.Id, err)
+					// Do not bail out because of one bad build.
+					// Also toMiloBuild almost never returns an error.
+					continue
+				}
+				*target = append(*target, mb)
+			}
+			return nil
+		}
+		// fetch pending, current and finished builds concurrently.
+		// Why not a single request? Because we need different build number
+		// limits for different statuses.
+		err = parallel.FanOutIn(func(work chan<- func() error) {
+			work <- func() error {
+				return fetch(&result.PendingBuilds, StatusScheduled, 0)
+			}
+			work <- func() error {
+				return fetch(&result.CurrentBuilds, StatusStarted, 0)
+			}
+			work <- func() error {
+				return fetch(&result.FinishedBuilds, StatusCompleted, maxCompletedBuilds)
+			}
+		})
+		if err != nil {
+			return result, err
+		}
+	}
+	return result, nil
+}
+
+// parseTimestamp converts buildbucket timestamp in microseconds to time.Time
+func parseTimestamp(microseconds int64) time.Time {
+	if microseconds == 0 {
+		return time.Time{}
+	}
+	return time.Unix(microseconds/1e6, microseconds%1e6*1000).UTC()
+}
+
+type newBuildsFirst []*resp.BuildSummary
+
+func (a newBuildsFirst) Len() int      { return len(a) }
+func (a newBuildsFirst) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
+func (a newBuildsFirst) Less(i, j int) bool {
+	return a[i].PendingTime.Started.After(a[j].PendingTime.Started)
+}