Add `needs` job output (#629)

* Add outputs field to job model

* Add output interpolation for jobs

* Add otto config reference for interpolated job output values into 'needs' context

* Add output interpolation call after job has completed.

* gofmt

* Remove whitespace

* goimports

Co-authored-by: Casey Lee <cplee@nektos.com>

pkg/model/workflow.go

@@ -66,6 +66,7 @@ type Job struct {
 	Strategy       *Strategy                 `yaml:"strategy"`
 	RawContainer   yaml.Node                 `yaml:"container"`
 	Defaults       Defaults                  `yaml:"defaults"`
+	Outputs        map[string]string         `yaml:"outputs"`
 }
 
 // Strategy for the job

pkg/model/workflow_test.go

@@ -131,6 +131,48 @@ jobs:
 	assert.Equal(t, workflow.Jobs["test"].Steps[4].Type(), StepTypeUsesActionLocal)
 }
 
+// See: https://docs.github.com/en/actions/reference/workflow-syntax-for-github-actions#jobsjob_idoutputs
+func TestReadWorkflow_JobOutputs(t *testing.T) {
+	yaml := `
+name: job outputs definition
+
+jobs:
+  test1:
+    runs-on: ubuntu-latest
+    steps:
+      - id: test1_1
+        run: |
+          echo "::set-output name=a_key::some-a_value"
+          echo "::set-output name=b-key::some-b-value"
+    outputs:
+      some_a_key: ${{ steps.test1_1.outputs.a_key }}
+      some-b-key: ${{ steps.test1_1.outputs.b-key }}
+
+  test2:
+    runs-on: ubuntu-latest
+    needs:
+      - test1
+    steps:
+      - name: test2_1
+        run: |
+          echo "${{ needs.test1.outputs.some_a_key }}"
+          echo "${{ needs.test1.outputs.some-b-key }}"
+`
+
+	workflow, err := ReadWorkflow(strings.NewReader(yaml))
+	assert.NoError(t, err, "read workflow should succeed")
+	assert.Len(t, workflow.Jobs, 2)
+
+	assert.Len(t, workflow.Jobs["test1"].Steps, 1)
+	assert.Equal(t, StepTypeRun, workflow.Jobs["test1"].Steps[0].Type())
+	assert.Equal(t, "test1_1", workflow.Jobs["test1"].Steps[0].ID)
+	assert.Len(t, workflow.Jobs["test1"].Outputs, 2)
+	assert.Contains(t, workflow.Jobs["test1"].Outputs, "some_a_key")
+	assert.Contains(t, workflow.Jobs["test1"].Outputs, "some-b-key")
+	assert.Equal(t, "${{ steps.test1_1.outputs.a_key }}", workflow.Jobs["test1"].Outputs["some_a_key"])
+	assert.Equal(t, "${{ steps.test1_1.outputs.b-key }}", workflow.Jobs["test1"].Outputs["some-b-key"])
+}
+
 func TestStep_ShellCommand(t *testing.T) {
 	tests := []struct {
 		shell string

pkg/runner/expression.go

@@ -229,6 +229,7 @@ func (rc *RunContext) newVM() *otto.Otto {
 		rc.vmStrategy(),
 		rc.vmMatrix(),
 		rc.vmEnv(),
+		rc.vmNeeds(),
 	}
 	vm := otto.New()
 	for _, configer := range configers {
@@ -415,6 +416,23 @@ func (sc *StepContext) vmInputs() func(*otto.Otto) {
 	}
 }
 
+func (rc *RunContext) vmNeeds() func(*otto.Otto) {
+	jobs := rc.Run.Workflow.Jobs
+	jobNeeds := rc.Run.Job().Needs()
+
+	using := make(map[string]map[string]map[string]string)
+	for _, needs := range jobNeeds {
+		using[needs] = map[string]map[string]string{
+			"outputs": jobs[needs].Outputs,
+		}
+	}
+
+	return func(vm *otto.Otto) {
+		log.Debugf("context needs => %v", using)
+		_ = vm.Set("needs", using)
+	}
+}
+
 func (rc *RunContext) vmJob() func(*otto.Otto) {
 	job := rc.getJobContext()
 

pkg/runner/run_context.go

@@ -262,7 +262,7 @@ func (rc *RunContext) newStepExecutor(step *model.Step) common.Executor {
 		rc.ExprEval = exprEval
 
 		common.Logger(ctx).Infof("\u2B50  Run %s", sc.Step)
-		err = sc.Executor()(ctx)
+		err = sc.Executor().Then(sc.interpolateOutputs())(ctx)
 		if err == nil {
 			common.Logger(ctx).Infof("  \u2705  Success - %s", sc.Step)
 		} else {

pkg/runner/step_context.go

@@ -29,6 +29,7 @@ type StepContext struct {
 	Env        map[string]string
 	Cmd        []string
 	Action     *model.Action
+	Needs      *model.Job
 }
 
 func (sc *StepContext) execJobContainer() common.Executor {
@@ -37,6 +38,19 @@ func (sc *StepContext) execJobContainer() common.Executor {
 	}
 }
 
+func (sc *StepContext) interpolateOutputs() common.Executor {
+	return func(ctx context.Context) error {
+		ee := sc.NewExpressionEvaluator()
+		for k, v := range sc.RunContext.Run.Job().Outputs {
+			interpolated := ee.Interpolate(v)
+			if v != interpolated {
+				sc.RunContext.Run.Job().Outputs[k] = interpolated
+			}
+		}
+		return nil
+	}
+}
+
 type formatError string
 
 func (e formatError) Error() string {