Use Runner

This revamps code quite a bit. Series handling has been moved into the
gerrit client, it also handles caching.

The Runner logic itself has been greatly simplified.

The runner logic has been moved into the runner.go, submitqueue.go is
gone.

The "per-run result object" concept has been dropped - we instead just
use annotated logs.

Also, we switched to apex/log

1 files changed, 122 insertions, 0 deletions

diff --git a/gerrit/series.go b/gerrit/series.go
new file mode 100644
index 000000000000..06d49805d35d
--- /dev/null
+++ b/gerrit/series.go
@@ -0,0 +1,122 @@
+package gerrit
+
+import (
+	"sort"
+
+	"github.com/apex/log"
+)
+
+// AssembleSeries consumes a list of `Changeset`, and groups them together to series
+//
+// We initially put every Changeset in its own Serie
+//
+// As we have no control over the order of the passed changesets,
+// we maintain a lookup table, mapLeafToSerie,
+// which allows to lookup a serie by its leaf commit id
+// We concat series in a fixpoint approach
+// because both appending and prepending is much more complex.
+// Concatenation moves changesets of the later changeset in the previous one
+// in a cleanup phase, we remove orphaned series (those without any changesets inside)
+// afterwards, we do an integrity check, just to be on the safe side.
+func AssembleSeries(changesets []*Changeset, log *log.Logger) ([]*Serie, error) {
+	series := make([]*Serie, 0)
+	mapLeafToSerie := make(map[string]*Serie, 0)
+
+	for _, changeset := range changesets {
+		logger := log.WithField("changeset", changeset.String())
+
+		logger.Debug("creating initial serie")
+		serie := &Serie{
+			ChangeSets: []*Changeset{changeset},
+		}
+		series = append(series, serie)
+		mapLeafToSerie[changeset.CommitID] = serie
+	}
+
+	// Combine series using a fixpoint approach, with a max iteration count.
+	log.Debug("glueing together phase")
+	for i := 1; i < 100; i++ {
+		didUpdate := false
+		log.Debugf("at iteration %d", i)
+		for _, serie := range series {
+			logger := log.WithField("serie", serie.String())
+			parentCommitIDs, err := serie.GetParentCommitIDs()
+			if err != nil {
+				return series, err
+			}
+			if len(parentCommitIDs) != 1 {
+				// We can't append merge commits to other series
+				logger.Infof("No single parent, skipping.")
+				continue
+			}
+			parentCommitID := parentCommitIDs[0]
+			logger.Debug("Looking for a predecessor.")
+			// if there's another serie that has this parent as a leaf, glue together
+			if otherSerie, ok := mapLeafToSerie[parentCommitID]; ok {
+				if otherSerie == serie {
+					continue
+				}
+				logger := logger.WithField("otherSerie", otherSerie)
+
+				myLeafCommitID, err := serie.GetLeafCommitID()
+				if err != nil {
+					return series, err
+				}
+
+				// append our changesets to the other serie
+				logger.Debug("Splicing together.")
+				otherSerie.ChangeSets = append(otherSerie.ChangeSets, serie.ChangeSets...)
+
+				delete(mapLeafToSerie, parentCommitID)
+				mapLeafToSerie[myLeafCommitID] = otherSerie
+
+				// orphan our serie
+				serie.ChangeSets = []*Changeset{}
+				// remove the orphaned serie from the lookup table
+				delete(mapLeafToSerie, myLeafCommitID)
+
+				didUpdate = true
+			} else {
+				logger.Debug("Not found.")
+			}
+		}
+		series = removeOrphanedSeries(series)
+		if !didUpdate {
+			log.Infof("converged after %d iterations", i)
+			break
+		}
+	}
+
+	// Check integrity, just to be on the safe side.
+	for _, serie := range series {
+		logger := log.WithField("serie", serie.String())
+		logger.Debugf("checking integrity")
+		err := serie.CheckIntegrity()
+		if err != nil {
+			logger.Errorf("checking integrity failed: %s", err)
+		}
+	}
+	return series, nil
+}
+
+// removeOrphanedSeries removes all empty series (that contain zero changesets)
+func removeOrphanedSeries(series []*Serie) []*Serie {
+	newSeries := []*Serie{}
+	for _, serie := range series {
+		if len(serie.ChangeSets) != 0 {
+			newSeries = append(newSeries, serie)
+		}
+	}
+	return newSeries
+}
+
+// SortSeries sorts a list of series by the number of changesets in each serie, descending
+func SortSeries(series []*Serie) []*Serie {
+	newSeries := make([]*Serie, len(series))
+	copy(newSeries, series)
+	sort.Slice(newSeries, func(i, j int) bool {
+		// the weight depends on the amount of changesets series changeset size
+		return len(series[i].ChangeSets) > len(series[j].ChangeSets)
+	})
+	return newSeries
+}