Adding a query param to return time series of stats

client/driver/executor/executor.go

@@ -27,6 +27,10 @@ import (
 	"github.com/hashicorp/nomad/nomad/structs"
 )
 
+const (
+	pidScanInterval = 5 * time.Second
+)
+
 // Executor is the interface which allows a driver to launch and supervise
 // a process
 type Executor interface {
@@ -631,7 +635,7 @@ func (e *UniversalExecutor) collectPids() {
 		case <-timer.C:
 			pids, err := e.getAllPids()
 			e.logger.Printf("DIPTANU PIDS %#v", pids)
-			timer.Reset(5 * time.Second)
+			timer.Reset(pidScanInterval)
 			if err != nil {
 				e.logger.Printf("[DEBUG] executor: error collecting pids: %v", err)
 			}
@@ -721,6 +725,5 @@ func (e *UniversalExecutor) resourceUsagePids() (*cstructs.TaskResourceUsage, er
 		Swap: totalSwap,
 	}
 
-	return &cstructs.TaskResourceUsage{MemoryStats: totalMemory, CpuStats: totalCPU}, nil
-
+	return &cstructs.TaskResourceUsage{MemoryStats: totalMemory, CpuStats: totalCPU, Timestamp: ts}, nil
 }

command/agent/stats_endpoint.go

@@ -3,6 +3,9 @@ package agent
 import (
 	"fmt"
 	"net/http"
+	"strconv"
+
+	"github.com/hashicorp/nomad/client"
 )
 
 func (s *HTTPServer) StatsRequest(resp http.ResponseWriter, req *http.Request) (interface{}, error) {
@@ -10,6 +13,15 @@ func (s *HTTPServer) StatsRequest(resp http.ResponseWriter, req *http.Request) (
 		return nil, clientNotRunning
 	}
 
+	var tsRequest bool
+
+	// Check if the user has requested time series
+	if qp := req.URL.Query().Get("ts"); qp != "" {
+		if tsReq, err := strconv.ParseBool(qp); err == nil {
+			tsRequest = tsReq
+		}
+	}
+
 	clientStats := s.agent.client.StatsReporter()
 
 	// Return the host stats if alloc ID is not present
@@ -30,14 +42,21 @@ func (s *HTTPServer) StatsRequest(resp http.ResponseWriter, req *http.Request) (
 		if err != nil {
 			return nil, err
 		}
-		return taskStats.ResourceUsage(), nil
+		return s.getStats(tsRequest, taskStats), nil
 	}
 
 	// Return the resource usage of all the tasks in an allocation if task name
 	// is not specified
 	res := make(map[string]interface{})
 	for task, taskStats := range allocStats.AllocStats() {
-		res[task] = taskStats.ResourceUsage()
+		res[task] = s.getStats(tsRequest, taskStats)
 	}
 	return res, nil
 }
+
+func (s *HTTPServer) getStats(tsRequest bool, taskStats client.TaskStatsReporter) interface{} {
+	if tsRequest {
+		return taskStats.ResourceUsageTS()
+	}
+	return taskStats.ResourceUsage()
+}