refactor: extract RunContext Executor in JobExecutor (#984)

This splits the executor from the RunContext into its own function
called newJobExecutor.
We defined an interface called jobInfo which is implemented by the RunContext.
This enables better unit testing because only a small interface needs to
be mocked.

This is a preparation for implementing pre and post actions.

Co-authored-by: Björn Brauer <bjoern.brauer@new-work.se>
Co-authored-by: Marcus Noll <marcus.noll@new-work.se>
Co-authored-by: Jonas Holland <jonas.holland@new-work.se>
Co-authored-by: Robert Kowalski <robert.kowalski@new-work.se>
Co-authored-by: Markus Wolf <markus.wolf@new-work.se>

Co-authored-by: Björn Brauer <bjoern.brauer@new-work.se>
Co-authored-by: Marcus Noll <marcus.noll@new-work.se>
Co-authored-by: Jonas Holland <jonas.holland@new-work.se>
Co-authored-by: Robert Kowalski <robert.kowalski@new-work.se>
Co-authored-by: Markus Wolf <markus.wolf@new-work.se>

go.sum

@@ -1117,6 +1117,7 @@ github.com/stefanberger/go-pkcs11uri v0.0.0-20201008174630-78d3cae3a980/go.mod h
 github.com/stretchr/objx v0.0.0-20180129172003-8a3f7159479f/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.2.0 h1:Hbg2NidpLE8veEBkEZTL3CvlkUIVzuU9jDplZO54c48=
 github.com/stretchr/objx v0.2.0/go.mod h1:qt09Ya8vawLte6SNmTgCsAVtYtaKzEcn8ATUoHMkEqE=
 github.com/stretchr/testify v0.0.0-20151208002404-e3a8ff8ce365/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v0.0.0-20180303142811-b89eecf5ca5d/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=

pkg/runner/job_executor.go

@@ -0,0 +1,71 @@
+package runner
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/nektos/act/pkg/common"
+	"github.com/nektos/act/pkg/model"
+)
+
+type jobInfo interface {
+	matrix() map[string]interface{}
+	steps() []*model.Step
+	startContainer() common.Executor
+	stopContainer() common.Executor
+	closeContainer() common.Executor
+	newStepExecutor(step *model.Step) common.Executor
+	interpolateOutputs() common.Executor
+	result(result string)
+}
+
+func newJobExecutor(info jobInfo) common.Executor {
+	steps := make([]common.Executor, 0)
+
+	steps = append(steps, func(ctx context.Context) error {
+		if len(info.matrix()) > 0 {
+			common.Logger(ctx).Infof("\U0001F9EA  Matrix: %v", info.matrix())
+		}
+		return nil
+	})
+
+	steps = append(steps, info.startContainer())
+
+	for i, step := range info.steps() {
+		if step.ID == "" {
+			step.ID = fmt.Sprintf("%d", i)
+		}
+		stepExec := info.newStepExecutor(step)
+		steps = append(steps, func(ctx context.Context) error {
+			err := stepExec(ctx)
+			if err != nil {
+				common.Logger(ctx).Errorf("%v", err)
+				common.SetJobError(ctx, err)
+			} else if ctx.Err() != nil {
+				common.Logger(ctx).Errorf("%v", ctx.Err())
+				common.SetJobError(ctx, ctx.Err())
+			}
+			return nil
+		})
+	}
+	steps = append(steps, func(ctx context.Context) error {
+		err := info.stopContainer()(ctx)
+		if err != nil {
+			return err
+		}
+
+		jobError := common.JobError(ctx)
+		if jobError != nil {
+			info.result("failure")
+		} else {
+			info.result("success")
+		}
+
+		return nil
+	})
+
+	return common.NewPipelineExecutor(steps...).Finally(info.interpolateOutputs()).Finally(func(ctx context.Context) error {
+		info.closeContainer()
+		return nil
+	})
+}

pkg/runner/job_executor_test.go

@@ -0,0 +1,135 @@
+package runner
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"github.com/nektos/act/pkg/common"
+	"github.com/nektos/act/pkg/model"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/mock"
+)
+
+type jobInfoMock struct {
+	mock.Mock
+}
+
+func (jpm *jobInfoMock) matrix() map[string]interface{} {
+	args := jpm.Called()
+	return args.Get(0).(map[string]interface{})
+}
+
+func (jpm *jobInfoMock) steps() []*model.Step {
+	args := jpm.Called()
+
+	return args.Get(0).([]*model.Step)
+}
+
+func (jpm *jobInfoMock) startContainer() common.Executor {
+	args := jpm.Called()
+
+	return args.Get(0).(func(context.Context) error)
+}
+
+func (jpm *jobInfoMock) stopContainer() common.Executor {
+	args := jpm.Called()
+
+	return args.Get(0).(func(context.Context) error)
+}
+
+func (jpm *jobInfoMock) closeContainer() common.Executor {
+	args := jpm.Called()
+
+	return args.Get(0).(func(context.Context) error)
+}
+
+func (jpm *jobInfoMock) newStepExecutor(step *model.Step) common.Executor {
+	args := jpm.Called(step)
+
+	return args.Get(0).(func(context.Context) error)
+}
+
+func (jpm *jobInfoMock) interpolateOutputs() common.Executor {
+	args := jpm.Called()
+
+	return args.Get(0).(func(context.Context) error)
+}
+
+func (jpm *jobInfoMock) result(result string) {
+	jpm.Called(result)
+}
+
+func TestNewJobExecutor(t *testing.T) {
+	table := []struct {
+		name     string
+		steps    []*model.Step
+		result   string
+		hasError bool
+	}{
+		{
+			"zeroSteps",
+			[]*model.Step{},
+			"success",
+			false,
+		},
+		{
+			"stepWithoutPrePost",
+			[]*model.Step{{
+				ID: "1",
+			}},
+			"success",
+			false,
+		},
+		{
+			"stepWithFailure",
+			[]*model.Step{{
+				ID: "1",
+			}},
+			"failure",
+			true,
+		},
+	}
+
+	for _, tt := range table {
+		t.Run(tt.name, func(t *testing.T) {
+			ctx := common.WithJobErrorContainer(context.Background())
+			jpm := &jobInfoMock{}
+
+			jpm.On("startContainer").Return(func(ctx context.Context) error {
+				return nil
+			})
+
+			jpm.On("steps").Return(tt.steps)
+
+			for _, stepMock := range tt.steps {
+				jpm.On("newStepExecutor", stepMock).Return(func(ctx context.Context) error {
+					if tt.hasError {
+						return fmt.Errorf("error")
+					}
+					return nil
+				})
+			}
+
+			jpm.On("interpolateOutputs").Return(func(ctx context.Context) error {
+				return nil
+			})
+
+			jpm.On("matrix").Return(map[string]interface{}{})
+
+			jpm.On("stopContainer").Return(func(ctx context.Context) error {
+				return nil
+			})
+
+			jpm.On("result", tt.result)
+
+			jpm.On("closeContainer").Return(func(ctx context.Context) error {
+				return nil
+			})
+
+			executor := newJobExecutor(jpm)
+			err := executor(ctx)
+			assert.Nil(t, err)
+		})
+	}
+}

pkg/runner/run_context.go

@@ -244,57 +244,38 @@ func (rc *RunContext) interpolateOutputs() common.Executor {
 	}
 }
 
-// Executor returns a pipeline executor for all the steps in the job
+func (rc *RunContext) startContainer() common.Executor {
-func (rc *RunContext) Executor() common.Executor {
+	return rc.startJobContainer()
-	steps := make([]common.Executor, 0)
+}
 
-	steps = append(steps, func(ctx context.Context) error {
+func (rc *RunContext) stopContainer() common.Executor {
-		if len(rc.Matrix) > 0 {
+	return rc.stopJobContainer()
-			common.Logger(ctx).Infof("\U0001F9EA  Matrix: %v", rc.Matrix)
+}
-		}
-		return nil
-	})
 
-	steps = append(steps, rc.startJobContainer())
+func (rc *RunContext) closeContainer() common.Executor {
-
+	return func(ctx context.Context) error {
-	for i, step := range rc.Run.Job().Steps {
-		if step.ID == "" {
-			step.ID = fmt.Sprintf("%d", i)
-		}
-		stepExec := rc.newStepExecutor(step)
-		steps = append(steps, func(ctx context.Context) error {
-			err := stepExec(ctx)
-			if err != nil {
-				common.Logger(ctx).Errorf("%v", err)
-				common.SetJobError(ctx, err)
-			} else if ctx.Err() != nil {
-				common.Logger(ctx).Errorf("%v", ctx.Err())
-				common.SetJobError(ctx, ctx.Err())
-			}
-			return nil
-		})
-	}
-	steps = append(steps, func(ctx context.Context) error {
-		err := rc.stopJobContainer()(ctx)
-		if err != nil {
-			return err
-		}
-
-		rc.Run.Job().Result = "success"
-		jobError := common.JobError(ctx)
-		if jobError != nil {
-			rc.Run.Job().Result = "failure"
-		}
-
-		return nil
-	})
-
-	return common.NewPipelineExecutor(steps...).Finally(rc.interpolateOutputs()).Finally(func(ctx context.Context) error {
 		if rc.JobContainer != nil {
 			return rc.JobContainer.Close()(ctx)
 		}
 		return nil
-	}).If(rc.isEnabled)
+	}
+}
+
+func (rc *RunContext) matrix() map[string]interface{} {
+	return rc.Matrix
+}
+
+func (rc *RunContext) result(result string) {
+	rc.Run.Job().Result = result
+}
+
+func (rc *RunContext) steps() []*model.Step {
+	return rc.Run.Job().Steps
+}
+
+// Executor returns a pipeline executor for all the steps in the job
+func (rc *RunContext) Executor() common.Executor {
+	return newJobExecutor(rc).If(rc.isEnabled)
 }
 
 // Executor returns a pipeline executor for all the steps in the job