feat: allow to spawn and run a local reusable workflow (#1423)

* feat: allow to spawn and run a local reusable workflow

This change contains the ability to parse/plan/run a local
reusable workflow.
There are still numerous things missing:

- inputs
- secrets
- outputs

* feat: add workflow_call inputs

* test: improve inputs test

* feat: add input defaults

* feat: allow expressions in inputs

* feat: use context specific expression evaluator

* refactor: prepare for better re-usability

* feat: add secrets for reusable workflows

* test: use secrets during test run

* feat: handle reusable workflow outputs

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

pkg/runner/expression.go

@@ -55,7 +55,7 @@ func (rc *RunContext) NewExpressionEvaluatorWithEnv(ctx context.Context, env map
 		// todo: should be unavailable
 		// but required to interpolate/evaluate the step outputs on the job
 		Steps:    rc.getStepsContext(),
-		Secrets:  rc.Config.Secrets,
+		Secrets:  getWorkflowSecrets(ctx, rc),
 		Strategy: strategy,
 		Matrix:   rc.Matrix,
 		Needs:    using,
@@ -101,7 +101,7 @@ func (rc *RunContext) NewStepExpressionEvaluator(ctx context.Context, step step)
 		Env:      *step.getEnv(),
 		Job:      rc.getJobContext(),
 		Steps:    rc.getStepsContext(),
-		Secrets:  rc.Config.Secrets,
+		Secrets:  getWorkflowSecrets(ctx, rc),
 		Strategy: strategy,
 		Matrix:   rc.Matrix,
 		Needs:    using,
@@ -315,6 +315,8 @@ func rewriteSubExpression(ctx context.Context, in string, forceFormat bool) (str
 func getEvaluatorInputs(ctx context.Context, rc *RunContext, step step, ghc *model.GithubContext) map[string]interface{} {
 	inputs := map[string]interface{}{}
 
+	setupWorkflowInputs(ctx, &inputs, rc)
+
 	var env map[string]string
 	if step != nil {
 		env = *step.getEnv()
@@ -347,3 +349,54 @@ func getEvaluatorInputs(ctx context.Context, rc *RunContext, step step, ghc *mod
 
 	return inputs
 }
+
+func setupWorkflowInputs(ctx context.Context, inputs *map[string]interface{}, rc *RunContext) {
+	if rc.caller != nil {
+		config := rc.Run.Workflow.WorkflowCallConfig()
+
+		for name, input := range config.Inputs {
+			value := rc.caller.runContext.Run.Job().With[name]
+			if value != nil {
+				if str, ok := value.(string); ok {
+					// evaluate using the calling RunContext (outside)
+					value = rc.caller.runContext.ExprEval.Interpolate(ctx, str)
+				}
+			}
+
+			if value == nil && config != nil && config.Inputs != nil {
+				value = input.Default
+				if rc.ExprEval != nil {
+					if str, ok := value.(string); ok {
+						// evaluate using the called RunContext (inside)
+						value = rc.ExprEval.Interpolate(ctx, str)
+					}
+				}
+			}
+
+			(*inputs)[name] = value
+		}
+	}
+}
+
+func getWorkflowSecrets(ctx context.Context, rc *RunContext) map[string]string {
+	if rc.caller != nil {
+		job := rc.caller.runContext.Run.Job()
+		secrets := job.Secrets()
+
+		if secrets == nil && job.InheritSecrets() {
+			secrets = rc.caller.runContext.Config.Secrets
+		}
+
+		if secrets == nil {
+			secrets = map[string]string{}
+		}
+
+		for k, v := range secrets {
+			secrets[k] = rc.caller.runContext.ExprEval.Interpolate(ctx, v)
+		}
+
+		return secrets
+	}
+
+	return rc.Config.Secrets
+}