tags/findSeries - add lastts-json format

api/graphite.go

@@ -686,8 +686,7 @@ func (s *Server) executePlan(ctx context.Context, orgId uint32, plan expr.Plan)
 			if err != nil {
 				return nil, meta, err
 			}
-
-			series, err = s.clusterFindByTag(ctx, orgId, exprs, int64(r.From), maxSeriesPerReq-len(reqs))
+			series, err = s.clusterFindByTag(ctx, orgId, exprs, int64(r.From), maxSeriesPerReq-len(reqs), false)
 		} else {
 			series, err = s.findSeries(ctx, orgId, []string{r.Query}, int64(r.From))
 		}
@@ -1012,7 +1011,16 @@ func (s *Server) graphiteTagFindSeries(ctx *middleware.Context, request models.G
 		return
 	}
 
-	series, err := s.clusterFindByTag(reqCtx, ctx.OrgId, expressions, request.From, maxSeriesPerReq)
+	// Out of the provided soft limit and the global `maxSeriesPerReq` hard limit
+	// (either of which may be 0 aka disabled), pick the only one that matters: the most strict one.
+	limit := request.Limit
+	isSoftLimit := limit > 0
+	if maxSeriesPerReq > 0 && (limit == 0 || limit > maxSeriesPerReq) {
+		limit = maxSeriesPerReq
+		isSoftLimit = false
+	}
+
+	series, err := s.clusterFindByTag(reqCtx, ctx.OrgId, expressions, request.From, limit, isSoftLimit)
 	if err != nil {
 		response.Write(ctx, response.WrapError(err))
 		return
@@ -1025,14 +1033,47 @@ func (s *Server) graphiteTagFindSeries(ctx *middleware.Context, request models.G
 		return
 	default:
 	}
-	seriesNames := make([]string, 0, len(series))
-	for _, serie := range series {
-		seriesNames = append(seriesNames, serie.Pattern)
+
+	var warnings []string
+	if len(series) == limit {
+		warnings = append(warnings, "Result set truncated due to limit")
+	}
+
+	switch request.Format {
+	case "lastts-json":
+		retval := models.GraphiteTagFindSeriesLastTsResp{Warnings: warnings}
+		retval.Series = make([]models.SeriesLastTs, 0, len(series))
+		for _, serie := range series {
+			var lastUpdate int64
+			for _, node := range serie.Series {
+				for _, ndef := range node.Defs {
+					if ndef.LastUpdate > lastUpdate {
+						lastUpdate = ndef.LastUpdate
+					}
+				}
+			}
+			retval.Series = append(retval.Series, models.SeriesLastTs{Series: serie.Pattern, Ts: lastUpdate})
+		}
+
+		response.Write(ctx, response.NewJson(200, retval, ""))
+	case "series-json":
+		seriesNames := make([]string, 0, len(series))
+		for _, serie := range series {
+			seriesNames = append(seriesNames, serie.Pattern)
+		}
+
+		if request.Meta == true {
+			retval := models.GraphiteTagFindSeriesMetaResp{Series: seriesNames, Warnings: warnings}
+			response.Write(ctx, response.NewJson(200, retval, ""))
+		} else {
+			response.Write(ctx, response.NewJson(200, seriesNames, ""))
+		}
 	}
-	response.Write(ctx, response.NewJson(200, seriesNames, ""))
 }
 
-func (s *Server) clusterFindByTag(ctx context.Context, orgId uint32, expressions tagquery.Expressions, from int64, maxSeries int) ([]Series, error) {
+// clusterFindByTag returns the Series matching the given expressions.
+// If maxSeries is > 0, it specifies a limit which will truncate the resultset (if softLimit is true) or return an error otherwise.
+func (s *Server) clusterFindByTag(ctx context.Context, orgId uint32, expressions tagquery.Expressions, from int64, maxSeries int, softLimit bool) ([]Series, error) {
 	data := models.IndexFindByTag{OrgId: orgId, Expr: expressions.Strings(), From: from}
 	newCtx, cancel := context.WithCancel(ctx)
 	defer cancel()
@@ -1047,8 +1088,21 @@ func (s *Server) clusterFindByTag(ctx context.Context, orgId uint32, expressions
 			return nil, err
 		}
 
-		// 0 disables the check, so only check if maxSeriesPerReq > 0
-		if maxSeriesPerReq > 0 && len(resp.Metrics)+len(allSeries) > maxSeries {
+		// Only check if maxSeriesPerReq > 0 (meaning enabled) or soft-limited
+		checkSeriesLimit := maxSeriesPerReq > 0 || softLimit
+		if checkSeriesLimit && len(resp.Metrics)+len(allSeries) > maxSeries {
+			if softLimit {
+				remainingSpace := maxSeries - len(allSeries)
+				// Fill in up to maxSeries
+				for _, series := range resp.Metrics[:remainingSpace] {
+					allSeries = append(allSeries, Series{
+						Pattern: series.Path,
+						Node:    r.peer,
+						Series:  []idx.Node{series},
+					})
+				}
+				return allSeries, nil
+			}
 			return nil,
 				response.NewError(
 					http.StatusRequestEntityTooLarge,

api/models/graphite.go

@@ -26,13 +26,16 @@ import (
 //msgp:ignore GraphiteTagDetailsValueResp
 //msgp:ignore GraphiteTagFindSeries
 //msgp:ignore GraphiteTagFindSeriesResp
+//msgp:ignore GraphiteTagFindSeriesLastTsResp
+//msgp:ignore GraphiteTagFindSeriesMetaResp
 //msgp:ignore GraphiteTagResp
 //msgp:ignore GraphiteTags
 //msgp:ignore GraphiteTagsResp
 //msgp:ignore MetricNames
 //msgp:ignore MetricsDelete
 //msgp:ignore SeriesCompleter
 //msgp:ignore SeriesCompleterItem
+//msgp:ignore SeriesLastTs
 //msgp:ignore SeriesTree
 //msgp:ignore SeriesTreeItem
 
@@ -117,14 +120,32 @@ type GraphiteTagDetailsValueResp struct {
 }
 
 type GraphiteTagFindSeries struct {
-	Expr []string `json:"expr" form:"expr"`
-	From int64    `json:"from" form:"from"`
+	Expr   []string `json:"expr" form:"expr"`
+	From   int64    `json:"from" form:"from"`
+	Format string   `json:"format" form:"format" binding:"In(,series-json,lastts-json);Default(series-json)"`
+	Limit  int      `json:"limit" binding:"Default(0)"`
+	Meta   bool     `json:"meta" binding:"Default(false)"`
 }
 
 type GraphiteTagFindSeriesResp struct {
 	Series []string `json:"series"`
 }
 
+type SeriesLastTs struct {
+	Series string `json:"val"`
+	Ts     int64  `json:"lastTs"`
+}
+
+type GraphiteTagFindSeriesLastTsResp struct {
+	Series   []SeriesLastTs `json:"series"`
+	Warnings []string       `json:"warnings,omitempty"`
+}
+
+type GraphiteTagFindSeriesMetaResp struct {
+	Series   []string `json:"series"`
+	Warnings []string `json:"warnings,omitempty"`
+}
+
 type GraphiteTagDelSeries struct {
 	Paths     []string `json:"path" form:"path"`
 	Propagate bool     `json:"propagate" form:"propagate" binding:"Default(true)"`

api/prometheus_querier.go

@@ -70,7 +70,7 @@ func (q *querier) Select(matchers ...*labels.Matcher) (storage.SeriesSet, error)
 		return nil, err
 	}
 
-	series, err := q.clusterFindByTag(q.ctx, q.OrgID, parsedExpressions, 0, maxSeriesPerReq)
+	series, err := q.clusterFindByTag(q.ctx, q.OrgID, parsedExpressions, 0, maxSeriesPerReq, false)
 	if err != nil {
 		return nil, err
 	}

docs/cloud/http-api.md

@@ -279,6 +279,11 @@ that duplicate entries will be returned.
 
 * expr (required): a list of [tag expressions](#tag-expressions)
 * from: Graphite [from time specification](#fromto) (optional. defaults to now-24hours)
+* format: series-json, lastts-json. (defaults to series-json)
+* limit: max number to return. (default: 0)
+  Note: the resultset is also subjected to the cluster configuration.
+  if the result set is larger than the cluster configuration, an error is returned. If it breaches the provided limit, the result is truncated.
+* meta: If false and format is `series-json` then return series names as array (graphite compatibility). If true, include meta information like warnings.  (defaults to false)
 
 ##### Example
 
@@ -290,6 +295,19 @@ curl -H "Authorization: Bearer $key" "$out/tags/findSeries?expr=datacenter=dc1&e
 ]
 ```
 
+```sh
+curl -H "Authorization: Bearer $key" "$out/tags/findSeries?expr=datacenter=dc1&expr=server=web01&format=lastts-json"
+
+{
+    "series": [
+        {
+            "lastTs": 1576683990,
+            "val": "disk.used;datacenter=dc1;rack=a1;server=web01"
+        }
+    ]
+}
+```
+
 ### Render `/render` (return data for a given query)
 
 Graphite-web-like api. It can return JSON, pickle or messagepack output

docs/http-api.md

@@ -66,6 +66,50 @@ json and treejson are the same.
 curl -H "X-Org-Id: 12345" "http://localhost:6060/metrics/find?query=statsd.fakesite.counters.session_start.*.count"
 ```
 
+## Find tagged metrics
+
+```
+GET /tags/findSeries
+POST /tags/findSeries
+```
+
+Returns metrics which match tag queries and have received an update since `from`.
+Note: the returned results are not deduplicated and in certain cases it is possible
+that duplicate entries will be returned.
+
+##### Parameters
+
+* expr (required): a list of [tag expressions](#tag-expressions)
+* from: Graphite [from time specification](#fromto) (optional. defaults to now-24hours)
+* format: series-json, lastts-json. (defaults to series-json)
+* limit: max number to return. (default: 0)
+  Note: the resultset is also subjected to the `http.max-series-per-req` config setting.
+  if the result set is larger than `http.max-series-per-req`, an error is returned. If it breaches the provided limit, the result is truncated.
+* meta: If false and format is `series-json` then return series names as array (graphite compatibility). If true, include meta information like warnings.  (defaults to false)
+
+##### Example
+
+```sh
+curl "http://localhost:6060/tags/findSeries?expr=datacenter=dc1&expr=server=web01"
+
+[
+  "disk.used;datacenter=dc1;rack=a1;server=web01"
+]
+```
+
+```sh
+curl "http://localhost:6060/tags/findSeries?expr=datacenter=dc1&expr=server=web01&format=lastts-json"
+
+{
+    "series": [
+        {
+            "lastTs": 1576683990,
+            "val": "disk.used;datacenter=dc1;rack=a1;server=web01"
+        }
+    ]
+}
+```
+
 ## Deleting metrics
 
 This will delete any metrics (technically metricdefinitions) matching the query from the index.
@@ -475,4 +519,3 @@ The time specification is used throughout the http api and it can be any of thes
 	- `y`, `year`, `years`
 
 * datetime in any of the following formats: `15:04 20060102`, `20060102`, `01/02/06`
-