enhance(local executor): print to stdout via client field

By printing to a stdout field on the local executor,
we can allow the (planned) tests to capture stdout
and make sure the executor is behaving correctly.

cmd/vela-worker/exec.go

@@ -69,6 +69,7 @@ func (w *Worker) exec(index int) error {
 	// https://godoc.org/github.com/go-vela/worker/executor#New
 	_executor, err := executor.New(&executor.Setup{
 		Logger:     logger,
+		Mock:       w.Config.Mock,
 		Driver:     w.Config.Executor.Driver,
 		LogMethod:  w.Config.Executor.LogMethod,
 		MaxLogSize: w.Config.Executor.MaxLogSize,

cmd/vela-worker/worker.go

@@ -46,6 +46,7 @@ type (
 
 	// Config represents the worker configuration.
 	Config struct {
+		Mock        bool // Mock should only true for tests
 		API         *API
 		Build       *Build
 		CheckIn     time.Duration

executor/local/api.go

@@ -7,7 +7,6 @@ package local
 import (
 	"context"
 	"fmt"
-	"os"
 	"time"
 
 	"github.com/go-vela/types/constants"
@@ -193,7 +192,7 @@ func (c *client) CancelBuild() (*library.Build, error) {
 
 	err = c.DestroyBuild(context.Background())
 	if err != nil {
-		fmt.Fprintln(os.Stdout, "unable to destroy build:", err)
+		fmt.Fprintln(c.stdout, "unable to destroy build:", err)
 	}
 
 	return b, nil

executor/local/build.go

@@ -7,7 +7,6 @@ package local
 import (
 	"context"
 	"fmt"
-	"os"
 	"sync"
 	"time"
 
@@ -97,7 +96,7 @@ func (c *client) PlanBuild(ctx context.Context) error {
 	}
 
 	// output init progress to stdout
-	fmt.Fprintln(os.Stdout, _pattern, "> Inspecting runtime network...")
+	fmt.Fprintln(c.stdout, _pattern, "> Inspecting runtime network...")
 
 	// inspect the runtime network for the pipeline
 	network, err := c.Runtime.InspectNetwork(ctx, c.pipeline)
@@ -107,7 +106,7 @@ func (c *client) PlanBuild(ctx context.Context) error {
 	}
 
 	// output the network information to stdout
-	fmt.Fprintln(os.Stdout, _pattern, string(network))
+	fmt.Fprintln(c.stdout, _pattern, string(network))
 
 	// create the runtime volume for the pipeline
 	err = c.Runtime.CreateVolume(ctx, c.pipeline)
@@ -117,7 +116,7 @@ func (c *client) PlanBuild(ctx context.Context) error {
 	}
 
 	// output init progress to stdout
-	fmt.Fprintln(os.Stdout, _pattern, "> Inspecting runtime volume...")
+	fmt.Fprintln(c.stdout, _pattern, "> Inspecting runtime volume...")
 
 	// inspect the runtime volume for the pipeline
 	volume, err := c.Runtime.InspectVolume(ctx, c.pipeline)
@@ -127,7 +126,7 @@ func (c *client) PlanBuild(ctx context.Context) error {
 	}
 
 	// output the volume information to stdout
-	fmt.Fprintln(os.Stdout, _pattern, string(volume))
+	fmt.Fprintln(c.stdout, _pattern, string(volume))
 
 	return c.err
 }
@@ -162,7 +161,7 @@ func (c *client) AssembleBuild(ctx context.Context) error {
 	}
 
 	// output init progress to stdout
-	fmt.Fprintln(os.Stdout, _pattern, "> Preparing service images...")
+	fmt.Fprintln(c.stdout, _pattern, "> Preparing service images...")
 
 	// create the services for the pipeline
 	for _, _service := range c.pipeline.Services {
@@ -183,11 +182,11 @@ func (c *client) AssembleBuild(ctx context.Context) error {
 		}
 
 		// output the image information to stdout
-		fmt.Fprintln(os.Stdout, _pattern, string(image))
+		fmt.Fprintln(c.stdout, _pattern, string(image))
 	}
 
 	// output init progress to stdout
-	fmt.Fprintln(os.Stdout, _pattern, "> Preparing stage images...")
+	fmt.Fprintln(c.stdout, _pattern, "> Preparing stage images...")
 
 	// create the stages for the pipeline
 	for _, _stage := range c.pipeline.Stages {
@@ -206,7 +205,7 @@ func (c *client) AssembleBuild(ctx context.Context) error {
 	}
 
 	// output init progress to stdout
-	fmt.Fprintln(os.Stdout, _pattern, "> Preparing step images...")
+	fmt.Fprintln(c.stdout, _pattern, "> Preparing step images...")
 
 	// create the steps for the pipeline
 	for _, _step := range c.pipeline.Steps {
@@ -229,11 +228,11 @@ func (c *client) AssembleBuild(ctx context.Context) error {
 		}
 
 		// output the image information to stdout
-		fmt.Fprintln(os.Stdout, _pattern, string(image))
+		fmt.Fprintln(c.stdout, _pattern, string(image))
 	}
 
 	// output a new line for readability to stdout
-	fmt.Fprintln(os.Stdout, "")
+	fmt.Fprintln(c.stdout, "")
 
 	// assemble runtime build just before any containers execute
 	c.err = c.Runtime.AssembleBuild(ctx, c.pipeline)
@@ -353,14 +352,14 @@ func (c *client) StreamBuild(ctx context.Context) error {
 	streams, streamCtx := errgroup.WithContext(ctx)
 
 	defer func() {
-		fmt.Fprintln(os.Stdout, "waiting for stream functions to return")
+		fmt.Fprintln(c.stdout, "waiting for stream functions to return")
 
 		err := streams.Wait()
 		if err != nil {
-			fmt.Fprintln(os.Stdout, "error in a stream request:", err)
+			fmt.Fprintln(c.stdout, "error in a stream request:", err)
 		}
 
-		fmt.Fprintln(os.Stdout, "all stream functions have returned")
+		fmt.Fprintln(c.stdout, "all stream functions have returned")
 	}()
 
 	// allow the runtime to do log/event streaming setup at build-level
@@ -374,11 +373,11 @@ func (c *client) StreamBuild(ctx context.Context) error {
 		select {
 		case req := <-c.streamRequests:
 			streams.Go(func() error {
-				fmt.Fprintf(os.Stdout, "[%s: %s] > Streaming container '%s'...\n", req.Key, req.Container.Name, req.Container.ID)
+				fmt.Fprintf(c.stdout, "[%s: %s] > Streaming container '%s'...\n", req.Key, req.Container.Name, req.Container.ID)
 
 				err := req.Stream(streamCtx, req.Container)
 				if err != nil {
-					fmt.Fprintln(os.Stdout, "error streaming:", err)
+					fmt.Fprintln(c.stdout, "error streaming:", err)
 				}
 
 				return nil
@@ -399,7 +398,7 @@ func (c *client) DestroyBuild(ctx context.Context) error {
 		err = c.Runtime.RemoveBuild(ctx, c.pipeline)
 		if err != nil {
 			// output the error information to stdout
-			fmt.Fprintln(os.Stdout, "unable to destroy runtime build:", err)
+			fmt.Fprintln(c.stdout, "unable to destroy runtime build:", err)
 		}
 	}()
 
@@ -414,7 +413,7 @@ func (c *client) DestroyBuild(ctx context.Context) error {
 		err = c.DestroyStep(ctx, _step)
 		if err != nil {
 			// output the error information to stdout
-			fmt.Fprintln(os.Stdout, "unable to destroy step:", err)
+			fmt.Fprintln(c.stdout, "unable to destroy step:", err)
 		}
 	}
 
@@ -429,7 +428,7 @@ func (c *client) DestroyBuild(ctx context.Context) error {
 		err = c.DestroyStage(ctx, _stage)
 		if err != nil {
 			// output the error information to stdout
-			fmt.Fprintln(os.Stdout, "unable to destroy stage:", err)
+			fmt.Fprintln(c.stdout, "unable to destroy stage:", err)
 		}
 	}
 
@@ -439,22 +438,22 @@ func (c *client) DestroyBuild(ctx context.Context) error {
 		err = c.DestroyService(ctx, _service)
 		if err != nil {
 			// output the error information to stdout
-			fmt.Fprintln(os.Stdout, "unable to destroy service:", err)
+			fmt.Fprintln(c.stdout, "unable to destroy service:", err)
 		}
 	}
 
 	// remove the runtime volume for the pipeline
 	err = c.Runtime.RemoveVolume(ctx, c.pipeline)
 	if err != nil {
 		// output the error information to stdout
-		fmt.Fprintln(os.Stdout, "unable to destroy runtime volume:", err)
+		fmt.Fprintln(c.stdout, "unable to destroy runtime volume:", err)
 	}
 
 	// remove the runtime network for the pipeline
 	err = c.Runtime.RemoveNetwork(ctx, c.pipeline)
 	if err != nil {
 		// output the error information to stdout
-		fmt.Fprintln(os.Stdout, "unable to destroy runtime network:", err)
+		fmt.Fprintln(c.stdout, "unable to destroy runtime network:", err)
 	}
 
 	return err

executor/local/local.go

@@ -5,6 +5,7 @@
 package local
 
 import (
+	"os"
 	"reflect"
 	"sync"
 
@@ -33,9 +34,24 @@ type (
 		user           *library.User
 		err            error
 		streamRequests chan message.StreamRequest
+
+		// internal field partially exported for tests
+		stdout           *os.File
+		mockStdoutReader *os.File
+	}
+
+	// MockedClient is for internal use to facilitate testing the local executor.
+	MockedClient interface {
+		MockStdout() *os.File
 	}
 )
 
+// MockStdout is for internal use to facilitate testing the local executor.
+// MockStdout returns a reader over a mocked Stdout.
+func (c *client) MockStdout() *os.File {
+	return c.mockStdoutReader
+}
+
 // equal returns true if the other client is the equivalent.
 func Equal(a, b *client) bool {
 	// handle any nil comparisons
@@ -64,6 +80,9 @@ func New(opts ...Opt) (*client, error) {
 	// create new local client
 	c := new(client)
 
+	// Add stdout by default
+	c.stdout = os.Stdout
+
 	// instantiate streamRequests channel (which may be overridden using withStreamRequests()).
 	c.streamRequests = make(chan message.StreamRequest)
 

executor/local/opts.go

@@ -6,6 +6,7 @@ package local
 
 import (
 	"fmt"
+	"os"
 
 	"github.com/go-vela/worker/internal/message"
 	"github.com/go-vela/worker/runtime"
@@ -121,6 +122,28 @@ func WithVersion(version string) Opt {
 	}
 }
 
+// WithMockStdout adds a mock stdout writer to the client if mock is true.
+// If mock is true, then you must use a goroutine to read from
+// MockStdout as quickly as possible, or writing to stdout will hang.
+func WithMockStdout(mock bool) Opt {
+	return func(c *client) error {
+		if !mock {
+			return nil
+		}
+
+		// New() sets c.stdout = os.stdout, replace it if a mock is required.
+		reader, writer, err := os.Pipe()
+		if err != nil {
+			return err
+		}
+
+		c.mockStdoutReader = reader
+		c.stdout = writer
+
+		return nil
+	}
+}
+
 // withStreamRequests sets the streamRequests channel in the executor client for Linux
 // (primarily used for tests).
 func withStreamRequests(s chan message.StreamRequest) Opt {

executor/local/service.go

@@ -8,7 +8,6 @@ import (
 	"bufio"
 	"context"
 	"fmt"
-	"os"
 	"time"
 
 	"github.com/go-vela/worker/internal/message"
@@ -125,7 +124,7 @@ func (c *client) StreamService(ctx context.Context, ctn *pipeline.Container) err
 	// scan entire container output
 	for scanner.Scan() {
 		// ensure we output to stdout
-		fmt.Fprintln(os.Stdout, _pattern, scanner.Text())
+		fmt.Fprintln(c.stdout, _pattern, scanner.Text())
 	}
 
 	return scanner.Err()

executor/local/stage.go

@@ -7,7 +7,6 @@ package local
 import (
 	"context"
 	"fmt"
-	"os"
 	"sync"
 
 	"github.com/go-vela/types/pipeline"
@@ -23,7 +22,7 @@ func (c *client) CreateStage(ctx context.Context, s *pipeline.Stage) error {
 	_pattern := fmt.Sprintf(stagePattern, c.init.Name, c.init.Name)
 
 	// output init progress to stdout
-	fmt.Fprintln(os.Stdout, _pattern, "> Preparing step images for stage", s.Name, "...")
+	fmt.Fprintln(c.stdout, _pattern, "> Preparing step images for stage", s.Name, "...")
 
 	// create the steps for the stage
 	for _, _step := range s.Steps {
@@ -43,7 +42,7 @@ func (c *client) CreateStage(ctx context.Context, s *pipeline.Stage) error {
 		}
 
 		// output the image information to stdout
-		fmt.Fprintln(os.Stdout, _pattern, string(image))
+		fmt.Fprintln(c.stdout, _pattern, string(image))
 	}
 
 	return nil
@@ -121,7 +120,7 @@ func (c *client) DestroyStage(ctx context.Context, s *pipeline.Stage) error {
 		// destroy the step
 		err = c.DestroyStep(ctx, _step)
 		if err != nil {
-			fmt.Fprintln(os.Stdout, "unable to destroy step: ", err)
+			fmt.Fprintln(c.stdout, "unable to destroy step: ", err)
 		}
 	}
 

executor/local/step.go

@@ -8,7 +8,6 @@ import (
 	"bufio"
 	"context"
 	"fmt"
-	"os"
 	"time"
 
 	"github.com/go-vela/types/constants"
@@ -164,7 +163,7 @@ func (c *client) StreamStep(ctx context.Context, ctn *pipeline.Container) error
 	// scan entire container output
 	for scanner.Scan() {
 		// ensure we output to stdout
-		fmt.Fprintln(os.Stdout, _pattern, scanner.Text())
+		fmt.Fprintln(c.stdout, _pattern, scanner.Text())
 	}
 
 	return scanner.Err()

executor/setup.go

@@ -31,6 +31,9 @@ type Setup struct {
 
 	// Executor Configuration
 
+	// Mock should only be true for tests.
+	Mock bool
+
 	// specifies the executor driver to use
 	Driver string
 	// specifies the executor method used to publish logs
@@ -106,6 +109,7 @@ func (s *Setup) Local() (Engine, error) {
 		local.WithUser(s.User),
 		local.WithVelaClient(s.Client),
 		local.WithVersion(s.Version),
+		local.WithMockStdout(s.Mock),
 	)
 }