status: make collectConstraints() concurrent

Author: darkowlzz

cmd/dep/status.go

@@ -685,34 +685,69 @@ type constraintsCollection map[string][]projectConstraint
 
 // collectConstraints collects constraints declared by all the dependencies.
 func collectConstraints(ctx *dep.Ctx, p *dep.Project, sm gps.SourceManager) constraintsCollection {
-	constraintCollection := make(constraintsCollection)
+	logger := ctx.Err
+	if !ctx.Verbose {
+		logger = log.New(ioutil.Discard, "", 0)
+	}
+
+	logger.Println("Collecting project constraints:")
 
 	// Get direct deps of the root project.
 	_, directDeps, err := getDirectDependencies(sm, p)
 	if err != nil {
-		ctx.Err.Println("Error getting direct deps:", err)
+		logger.Println("Error getting direct deps:", err)
 	}
+
 	// Create a root analyzer.
 	rootAnalyzer := newRootAnalyzer(true, ctx, directDeps, sm)
 
+	lp := p.Lock.Projects()
+
+	var mutex sync.Mutex
+	constraintCollection := make(constraintsCollection)
+
+	// Channel for receiving all the errors.
+	errCh := make(chan error, len(lp))
+
+	var wg sync.WaitGroup
+
 	// Iterate through the locked projects and collect constraints of all the projects.
-	for _, proj := range p.Lock.Projects() {
-		manifest, _, err := sm.GetManifestAndLock(proj.Ident(), proj.Version(), rootAnalyzer)
-		if err != nil {
-			ctx.Err.Println("Error getting manifest and lock:", err)
-			continue
-		}
+	for i, proj := range lp {
+		wg.Add(1)
+		logger.Printf("(%d/%d) %s\n", i+1, len(lp), proj.Ident().ProjectRoot)
+
+		go func(proj gps.LockedProject) {
+			defer wg.Done()
+
+			manifest, _, err := sm.GetManifestAndLock(proj.Ident(), proj.Version(), rootAnalyzer)
+			if err != nil {
+				errCh <- errors.Wrap(err, "error getting manifest and lock")
+				return
+			}
+
+			// Get project constraints.
+			pc := manifest.DependencyConstraints()
+
+			// Obtain a lock for constraintCollection.
+			mutex.Lock()
+			defer mutex.Unlock()
+			// Iterate through the project constraints to get individual dependency
+			// project and constraint values.
+			for pr, pp := range pc {
+				constraintCollection[string(pr)] = append(
+					constraintCollection[string(pr)],
+					projectConstraint{proj.Ident().ProjectRoot, pp.Constraint},
+				)
+			}
+		}(proj)
+	}
 
-		// Get project constraints.
-		pc := manifest.DependencyConstraints()
+	wg.Wait()
+	close(errCh)
 
-		// Iterate through the project constraints to get individual dependency
-		// project and constraint values.
-		for pr, pp := range pc {
-			constraintCollection[string(pr)] = append(
-				constraintCollection[string(pr)],
-				projectConstraint{proj.Ident().ProjectRoot, pp.Constraint},
-			)
+	if len(errCh) > 0 {
+		for err := range errCh {
+			logger.Println(err.Error())
 		}
 	}