Update Prometheus vendoring, adapt Cortex (#668)

* Update vendored Prometheus packages and transient deps

* Make Cortex work with updated Prometheus packages

The most noticeable change is around the lifecycle manager of the Alertmanager
notifier and its associated service discovery manager. This has now been moved
from the notifier package into main.go in Prometheus and thus we also need to
duplicate that lifecycle management ourselves.

* Ruler comment fixups / additions

Author: juliusv

Gopkg.lock

@@ -22,16 +22,6 @@
   name = "github.com/Azure/azure-sdk-for-go"
   revision = "bd73d950fa4440dae889bd9917bff7cef539f86e"
 
-[[override]]
-  name = "github.com/prometheus/common"
-  revision = "1bab55dd05dbff384524a6a1c99006d9eb5f139b"
-
 [[override]]
   name = "github.com/weaveworks/mesh"
   revision = "5015f896ab62d3e9fe757456c757521ce0c3faff"
-
-[[override]]
-  name = "github.com/grpc-ecosystem/grpc-gateway"
-  # This version is currently vendored in github.com/prometheus/prometheus,
-  # and newer versions have changed method signatures, so break the build.
-  revision = "589b126116b5fc961939b3e156c29e4d9d58222f"

Gopkg.toml

@@ -13,6 +13,7 @@ import (
 	"github.com/prometheus/prometheus/config"
 	"github.com/prometheus/prometheus/promql"
 	"github.com/prometheus/prometheus/web/api/v1"
+	"github.com/prometheus/tsdb"
 	"google.golang.org/grpc"
 
 	"github.com/weaveworks/common/middleware"
@@ -155,6 +156,8 @@ func main() {
 		querier.DummyAlertmanagerRetriever{},
 		func() config.Config { return config.Config{} },
 		func(f http.HandlerFunc) http.HandlerFunc { return f },
+		func() *tsdb.DB { return nil }, // Only needed for admin APIs.
+		false, // Disable admin APIs.
 	)
 	promRouter := route.New().WithPrefix("/api/prom/api/v1")
 	api.Register(promRouter)

cmd/lite/main.go

@@ -13,6 +13,7 @@ import (
 	"github.com/prometheus/prometheus/config"
 	"github.com/prometheus/prometheus/promql"
 	"github.com/prometheus/prometheus/web/api/v1"
+	"github.com/prometheus/tsdb"
 
 	"github.com/weaveworks/common/middleware"
 	"github.com/weaveworks/common/server"
@@ -98,6 +99,8 @@ func main() {
 		querier.DummyAlertmanagerRetriever{},
 		func() config.Config { return config.Config{} },
 		func(f http.HandlerFunc) http.HandlerFunc { return f },
+		func() *tsdb.DB { return nil }, // Only needed for admin APIs.
+		false, // Disable admin APIs.
 	)
 	promRouter := route.New().WithPrefix("/api/prom/api/v1")
 	api.Register(promRouter)

cmd/querier/main.go

@@ -195,27 +195,28 @@ type mergeQuerier struct {
 	metadataOnly bool
 }
 
-func (mq mergeQuerier) Select(matchers ...*labels.Matcher) storage.SeriesSet {
+func (mq mergeQuerier) Select(matchers ...*labels.Matcher) (storage.SeriesSet, error) {
+	// TODO: Update underlying selectors to return errors directly.
 	if mq.metadataOnly {
-		return mq.selectMetadata(matchers...)
+		return mq.selectMetadata(matchers...), nil
 	}
-	return mq.selectSamples(matchers...)
+	return mq.selectSamples(matchers...), nil
 }
 
 func (mq mergeQuerier) selectMetadata(matchers ...*labels.Matcher) storage.SeriesSet {
 	// NB that we don't do this in parallel, as in practice we only have two queriers,
 	// one of which is the chunk store, which doesn't implement this yet.
-	var set storage.SeriesSet
+	seriesSets := make([]storage.SeriesSet, 0, len(mq.queriers))
 	for _, q := range mq.queriers {
 		ms, err := q.MetricsForLabelMatchers(mq.ctx, model.Time(mq.mint), model.Time(mq.maxt), matchers...)
 		if err != nil {
 			return errSeriesSet{err: err}
 		}
 		ss := metricsToSeriesSet(ms)
-		set = storage.DeduplicateSeriesSet(set, ss)
+		seriesSets = append(seriesSets, ss)
 	}
 
-	return set
+	return storage.NewMergeSeriesSet(seriesSets)
 }
 
 func (mq mergeQuerier) selectSamples(matchers ...*labels.Matcher) storage.SeriesSet {

pkg/querier/querier.go

@@ -110,7 +110,8 @@ func TestMergeQuerierSortsMetricLabels(t *testing.T) {
 	}
 	m, err := labels.NewMatcher(labels.MatchEqual, model.MetricNameLabel, "testmetric")
 	require.NoError(t, err)
-	ss := mq.Select(m)
+	ss, err := mq.Select(m)
+	require.NoError(t, err)
 	require.NoError(t, ss.Err())
 	ss.Next()
 	require.NoError(t, ss.Err())