service: simplify Logs() & improve docs

service/dependency.go

@@ -1,13 +1,5 @@
 package service
 
-import (
-	"io"
-
-	"github.com/docker/docker/pkg/stdcopy"
-	"github.com/mesg-foundation/core/container"
-	"github.com/sirupsen/logrus"
-)
-
 // Dependency represents a Docker container and it holds instructions about
 // how it should run.
 type Dependency struct {
@@ -35,22 +27,3 @@ type Dependency struct {
 	// Env is a slice of environment variables in key=value format.
 	Env []string `hash:"name:8"`
 }
-
-// Logs gives the dependency logs. rstd stands for standard logs and rerr stands for
-// error logs.
-func (d *Dependency) Logs(c container.Container, serviceNamespace []string) (rstd, rerr io.ReadCloser, err error) {
-	var reader io.ReadCloser
-	reader, err = c.ServiceLogs(d.namespace(serviceNamespace))
-	if err != nil {
-		return nil, nil, err
-	}
-	sr, sw := io.Pipe()
-	er, ew := io.Pipe()
-	go func() {
-		if _, err := stdcopy.StdCopy(sw, ew, reader); err != nil {
-			reader.Close()
-			logrus.Errorln(err)
-		}
-	}()
-	return sr, er, nil
-}

service/dependency_test.go

@@ -1,75 +1 @@
 package service
-
-import (
-	"io"
-	"sync"
-	"testing"
-
-	"github.com/docker/docker/pkg/stdcopy"
-	"github.com/mesg-foundation/core/container"
-	"github.com/mesg-foundation/core/container/mocks"
-	"github.com/stretchr/testify/require"
-)
-
-func TestDependencyLogs(t *testing.T) {
-	testDependencyLogs(t, func(s *Service, c container.Container, dependencyKey string) (rstd, rerr io.ReadCloser,
-		err error) {
-		dep, err := s.getDependency(dependencyKey)
-		require.NoError(t, err)
-		return dep.Logs(c, s.namespace())
-	})
-}
-
-func testDependencyLogs(t *testing.T, do func(s *Service, c container.Container, dependencyKey string) (rstd, rerr io.ReadCloser,
-	err error)) {
-	var (
-		dependencyKey = "1"
-		stdData       = []byte{1, 2}
-		errData       = []byte{3, 4}
-	)
-
-	rp, wp := io.Pipe()
-	wstd := stdcopy.NewStdWriter(wp, stdcopy.Stdout)
-	werr := stdcopy.NewStdWriter(wp, stdcopy.Stderr)
-
-	go wstd.Write(stdData)
-	go werr.Write(errData)
-
-	var (
-		s = &Service{
-			Hash: "1",
-			Dependencies: []*Dependency{
-				{Key: dependencyKey},
-			},
-		}
-		mc = &mocks.Container{}
-	)
-
-	d, _ := s.getDependency(dependencyKey)
-	mc.On("ServiceLogs", d.namespace(s.namespace())).Once().Return(rp, nil)
-
-	rstd, rerr, err := do(s, mc, dependencyKey)
-	require.NoError(t, err)
-
-	var wg sync.WaitGroup
-	wg.Add(2)
-
-	go func() {
-		defer wg.Done()
-		buf := make([]byte, 2)
-		_, err := rstd.Read(buf)
-		require.NoError(t, err)
-		require.Equal(t, stdData, buf)
-	}()
-
-	go func() {
-		defer wg.Done()
-		buf := make([]byte, 2)
-		_, err = rerr.Read(buf)
-		require.NoError(t, err)
-		require.Equal(t, errData, buf)
-	}()
-
-	wg.Wait()
-	mc.AssertExpectations(t)
-}

service/logs.go

@@ -3,8 +3,10 @@ package service
 import (
 	"io"
 
+	"github.com/docker/docker/pkg/stdcopy"
 	"github.com/mesg-foundation/core/container"
 	"github.com/mesg-foundation/core/x/xstrings"
+	"github.com/sirupsen/logrus"
 )
 
 // Log holds log streams of dependency.
@@ -14,36 +16,40 @@ type Log struct {
 	Error      io.ReadCloser
 }
 
-// Logs gives service's logs and applies dependencies filter to filter logs.
-// if dependencies has a length of zero all dependency logs will be provided.
+// Logs gives service's logs streams. when dependencies filter is not provided, it'll give
+// logs for all dependencies otherwise it'll only give logs for specified dependencies.
+// note that, service itself is also a dependency defined with special "service" key.
+// in order to get service's own logs, "service" key must be included to dependencies filter.
 func (s *Service) Logs(c container.Container, dependencies ...string) ([]*Log, error) {
 	var (
 		logs       []*Log
 		isNoFilter = len(dependencies) == 0
 	)
-	addLog := func(dep *Dependency, name string) error {
-		if isNoFilter || xstrings.SliceContains(dependencies, name) {
-			rstd, rerr, err := dep.Logs(c, s.namespace())
+	for _, d := range append(s.Dependencies, s.Configuration) {
+		// Service.Configuration can be nil so, here is a check for it.
+		if d == nil {
+			continue
+		}
+		if isNoFilter || xstrings.SliceContains(dependencies, d.Key) {
+			var r io.ReadCloser
+			r, err := c.ServiceLogs(d.namespace(s.namespace()))
 			if err != nil {
-				return err
+				return nil, err
 			}
+			rstd, sw := io.Pipe()
+			rerr, ew := io.Pipe()
+			go func(dstout, dsterr io.Writer, r io.ReadCloser) {
+				if _, err := stdcopy.StdCopy(dstout, dsterr, r); err != nil {
+					r.Close()
+					logrus.Errorln(err)
+				}
+			}(sw, ew, r)
 			logs = append(logs, &Log{
-				Dependency: name,
+				Dependency: d.Key,
 				Standard:   rstd,
 				Error:      rerr,
 			})
 		}
-		return nil
-	}
-	if s.Configuration != nil {
-		if err := addLog(s.Configuration, MainServiceKey); err != nil {
-			return nil, err
-		}
-	}
-	for _, dep := range s.Dependencies {
-		if err := addLog(dep, dep.Key); err != nil {
-			return nil, err
-		}
 	}
 	return logs, nil
 }

service/logs_test.go

@@ -2,18 +2,65 @@ package service
 
 import (
 	"io"
+	"sync"
 	"testing"
 
-	"github.com/mesg-foundation/core/container"
+	"github.com/docker/docker/pkg/stdcopy"
+	"github.com/mesg-foundation/core/container/mocks"
 	"github.com/stretchr/testify/require"
 )
 
 func TestServiceLogs(t *testing.T) {
-	testDependencyLogs(t, func(s *Service, c container.Container, dependencyKey string) (rstd, rerr io.ReadCloser,
-		err error) {
-		l, err := s.Logs(c, dependencyKey)
+	var (
+		dependencyKey = "1"
+		stdData       = []byte{1, 2}
+		errData       = []byte{3, 4}
+	)
+
+	rp, wp := io.Pipe()
+	wstd := stdcopy.NewStdWriter(wp, stdcopy.Stdout)
+	werr := stdcopy.NewStdWriter(wp, stdcopy.Stderr)
+
+	go wstd.Write(stdData)
+	go werr.Write(errData)
+
+	var (
+		s = &Service{
+			Hash: "1",
+			Dependencies: []*Dependency{
+				{Key: dependencyKey},
+			},
+		}
+		mc = &mocks.Container{}
+	)
+
+	d, _ := s.getDependency(dependencyKey)
+	mc.On("ServiceLogs", d.namespace(s.namespace())).Once().Return(rp, nil)
+
+	l, err := s.Logs(mc, dependencyKey)
+	require.NoError(t, err)
+	require.Len(t, l, 1)
+	rstd, rerr := l[0].Standard, l[0].Error
+
+	var wg sync.WaitGroup
+	wg.Add(2)
+
+	go func() {
+		defer wg.Done()
+		buf := make([]byte, 2)
+		_, err := rstd.Read(buf)
 		require.NoError(t, err)
-		require.Len(t, l, 1)
-		return l[0].Standard, l[0].Error, nil
-	})
+		require.Equal(t, stdData, buf)
+	}()
+
+	go func() {
+		defer wg.Done()
+		buf := make([]byte, 2)
+		_, err = rerr.Read(buf)
+		require.NoError(t, err)
+		require.Equal(t, errData, buf)
+	}()
+
+	wg.Wait()
+	mc.AssertExpectations(t)
 }