DRIVERS-3264 Use first task and variant of the project by default for perf filtering (#715)

Author: blink1073

.evergreen/perfcomp/README.md

@@ -37,6 +37,9 @@ db.raw_results.find({
 
 and look for the `variant` and `task_name` properties.
 
+If you do not provide either the `variant` or `task_name`, they will be inferred by looking for the most recent
+perf data for the given `project`.
+
 ### perfcomp CLI
 
 ```bash
@@ -63,8 +66,8 @@ Usage:
 Flags:
   --perf-context string   specify the performance triage context, ex. "GoDriver perf task" (required)
   --project      string   specify the name of an existing Evergreen project, ex. "mongo-go-driver" (required)
-  --task         string   specify the evergreen perf task name, ex. "perf" (required)
-  --variant      string   specify the perf task variant, ex. "perf" (required)
+  --task         string   specify the evergreen perf task name, ex. "perf" (optional)
+  --variant      string   specify the perf task variant, ex. "perf" (optional)
 ```
 
 #### mdreport

.evergreen/perfcomp/cmd/perfcomp/compare.go

@@ -31,12 +31,13 @@ func newCompareCommand() *cobra.Command {
 	var project, task, variant, perfcontext string
 	cmd.Flags().StringVar(&project, "project", "", `specify the name of an existing Evergreen project, ex. "mongo-go-driver"`)
 	cmd.Flags().StringVar(&perfcontext, "perf-context", "", `specify the performance triage context, ex. "GoDriver perf task"`)
-	// TODO(DRIVERS-3264): Use first task / variant of the project by default for perf filtering
 	cmd.Flags().StringVar(&task, "task", "", `specify the evergreen performance task name, ex. "perf"`)
 	cmd.Flags().StringVar(&variant, "variant", "", `specify the performance variant, ex. "perf"`)
 
-	for _, flag := range []string{"project", "task", "variant", "context"} {
-		cmd.MarkFlagRequired(flag)
+	for _, flag := range []string{"project", "perf-context"} {
+		if flag == "" {
+			log.Fatalf("must provide %s", flag)
+		}
 	}
 
 	cmd.Run = func(cmd *cobra.Command, args []string) {
@@ -47,12 +48,27 @@ func newCompareCommand() *cobra.Command {
 		}
 
 		// Validate all flags
-		for _, flag := range []string{"project", "task", "variant", "perf-context"} {
+		for _, flag := range []string{"project", "perf-context"} {
 			if flag == "" {
 				log.Fatalf("must provide %s", flag)
 			}
 		}
 
+		// Fetch default task and variant if either not are provided
+		if task == "" || variant == "" {
+			var err error
+			task, variant, err = perfcomp.GetDefaultTaskAndVariant(uri, project, task, variant)
+			if err != nil {
+				log.Fatalf("failed to fetch task/variant defaults: %v", err)
+			}
+			if task != "" {
+				log.Printf("Using task: %s\n", task)
+			}
+			if variant != "" {
+				log.Printf("Using variant: %s\n", variant)
+			}
+		}
+
 		// Run compare function
 		err := runCompare(cmd, args,
 			perfcomp.WithProject(project),

.evergreen/perfcomp/compare.go

@@ -179,6 +179,60 @@ func validateOptions(copts CompareOptions) error {
 	return nil
 }
 
+// GetDefaultTaskAndVariant will find the default task and/or variant for a given project
+// using the most recent result in the raw_results collection.
+func GetDefaultTaskAndVariant(perfAnalyticsConnString, project, task, variant string) (string, string, error) {
+	// Connect to analytics node
+	client, err := mongo.Connect(options.Client().ApplyURI(perfAnalyticsConnString))
+	if err != nil {
+		return "", "", fmt.Errorf("error connecting client: %v", err)
+	}
+
+	fmt.Println("Successfully connected to MongoDB")
+
+	defer func() { // Defer disconnect client
+		err = client.Disconnect(context.Background())
+		if err != nil {
+			log.Fatalf("failed to disconnect client: %v", err)
+		}
+	}()
+
+	// Reference the collection in the database
+	collection := client.Database(expandedMetricsDB).Collection(rawResultsColl)
+
+	// Build filter for querying raw_results
+	filter := bson.M{
+		"info.project": project,
+	}
+	if task != "" {
+		filter["info.task_name"] = task
+	}
+	if variant != "" {
+		filter["info.variant"] = variant
+	}
+
+	// Set sort options for the query
+	opts := options.FindOne().SetSort(bson.D{{Key: "created_at", Value: -1}}) // Sort by latest date
+
+	// Execute the query
+	var result RawData
+	findCtx, findCancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer findCancel()
+
+	err = collection.FindOne(findCtx, filter, opts).Decode(&result)
+	if err != nil {
+		if err == mongo.ErrNoDocuments {
+			fmt.Printf("No matching raw results found for project: %s\n", project)
+			return "", "", fmt.Errorf("no matching raw results found for project: %s", project)
+		}
+		fmt.Printf("Failed to fetch defaults for project %s. Error: %v\n", project, err)
+		return "", "", fmt.Errorf("failed to fetch defaults for project %s: %v", project, err)
+	}
+
+	// Return the extracted values
+	return result.Info.TaskName, result.Info.Variant, nil
+}
+
 // Compare will return statistical results for a patch version using the
 // stable region defined by the performance analytics cluster.
 func Compare(ctx context.Context, perfAnalyticsConnString string, opts ...CompareOption) (*CompareResult, error) {

.evergreen/run-perf-comp.sh

@@ -62,10 +62,8 @@ fi
 : "${VERSION_ID:?Error: VERSION_ID must be set}"
 : "${PROJECT:?Error: PROJECT must be set}"
 : "${CONTEXT:?Error: CONTEXT must be set}"
-: "${TASK:?Error: TASKNAME must be set}"
-: "${VARIANT:?Error: VARIANT must be set}"
 
-./bin/perfcomp compare --project ${PROJECT} --perf-context "${CONTEXT}" --task ${TASK} --variant ${VARIANT} ${VERSION_ID}
+./bin/perfcomp compare --project ${PROJECT} --perf-context "${CONTEXT}" --task ${TASK:-} --variant ${VARIANT:-} ${VERSION_ID}
 
 if [[ -n "${HEAD_SHA+set}" ]]; then
   ./bin/perfcomp mdreport