Implement the debug flag and help command

I'm vacillating about the choice to have separate Config structs in the
`helm` and `run` packages. I can't tell whether it's "good separation of
concerns" or "cumbersome and over-engineered." It seems appropriate at
the moment, though.

internal/helm/plan.go

@@ -2,12 +2,15 @@ package helm
 
 import (
 	"errors"
+	"fmt"
 	"github.com/pelotech/drone-helm3/internal/run"
+	"os"
 )
 
 // A Step is one step in the plan.
 type Step interface {
-	Run() error
+	Prepare(run.Config) error
+	Execute() error
 }
 
 // A Plan is a series of steps to perform.
@@ -17,10 +20,26 @@ type Plan struct {
 
 // NewPlan makes a plan for running a helm operation.
 func NewPlan(cfg Config) (*Plan, error) {
+	runCfg := run.Config{
+		Debug:          cfg.Debug,
+		KubeConfig:     cfg.KubeConfig,
+		Values:         cfg.Values,
+		StringValues:   cfg.StringValues,
+		ValuesFiles:    cfg.ValuesFiles,
+		Namespace:      cfg.Namespace,
+		Token:          cfg.Token,
+		SkipTLSVerify:  cfg.SkipTLSVerify,
+		Certificate:    cfg.Certificate,
+		APIServer:      cfg.APIServer,
+		ServiceAccount: cfg.ServiceAccount,
+		Stdout:         os.Stdout,
+		Stderr:         os.Stderr,
+	}
+
 	p := Plan{}
 	switch cfg.Command {
 	case "upgrade":
-		steps, err := upgrade(cfg)
+		steps, err := upgrade(cfg, runCfg)
 		if err != nil {
 			return nil, err
 		}
@@ -30,11 +49,15 @@ func NewPlan(cfg Config) (*Plan, error) {
 	case "lint":
 		return nil, errors.New("not implemented")
 	case "help":
-		return nil, errors.New("not implemented")
+		steps, err := help(cfg, runCfg)
+		if err != nil {
+			return nil, err
+		}
+		p.steps = steps
 	default:
 		switch cfg.DroneEvent {
 		case "push", "tag", "deployment", "pull_request", "promote", "rollback":
-			steps, err := upgrade(cfg)
+			steps, err := upgrade(cfg, runCfg)
 			if err != nil {
 				return nil, err
 			}
@@ -50,7 +73,7 @@ func NewPlan(cfg Config) (*Plan, error) {
 // Execute runs each step in the plan, aborting and reporting on error
 func (p *Plan) Execute() error {
 	for _, step := range p.steps {
-		if err := step.Run(); err != nil {
+		if err := step.Execute(); err != nil {
 			return err
 		}
 	}
@@ -58,9 +81,33 @@ func (p *Plan) Execute() error {
 	return nil
 }
 
-func upgrade(cfg Config) ([]Step, error) {
+func upgrade(cfg Config, runCfg run.Config) ([]Step, error) {
 	steps := make([]Step, 0)
-	steps = append(steps, run.NewUpgrade(cfg.Release, cfg.Chart))
+	upgrade := &run.Upgrade{
+		Chart:        cfg.Chart,
+		Release:      cfg.Release,
+		ChartVersion: cfg.ChartVersion,
+		Wait:         cfg.Wait,
+		ReuseValues:  cfg.ReuseValues,
+		Timeout:      cfg.Timeout,
+		Force:        cfg.Force,
+	}
+	if err := upgrade.Prepare(runCfg); err != nil {
+		err = fmt.Errorf("while preparing upgrade step: %w", err)
+		return steps, err
+	}
+	steps = append(steps, upgrade)
 
 	return steps, nil
 }
+
+func help(cfg Config, runCfg run.Config) ([]Step, error) {
+	help := &run.Help{}
+
+	if err := help.Prepare(runCfg); err != nil {
+		err = fmt.Errorf("while preparing help step: %w", err)
+		return []Step{}, err
+	}
+
+	return []Step{help}, nil
+}

internal/helm/plan_test.go

@@ -25,15 +25,13 @@ func (suite *PlanTestSuite) TestNewPlanUpgradeCommand() {
 
 	plan, err := NewPlan(cfg)
 	suite.Require().Nil(err)
-	suite.Equal(1, len(plan.steps))
+	suite.Require().Equal(1, len(plan.steps))
 
-	switch step := plan.steps[0].(type) {
-	case *run.Upgrade:
-		suite.Equal("billboard_top_100", step.Chart)
-		suite.Equal("post_malone_circles", step.Release)
-	default:
-		suite.Failf("Wrong type for step 1", "Expected Upgrade, got %T", step)
-	}
+	suite.Require().IsType(&run.Upgrade{}, plan.steps[0])
+	step, _ := plan.steps[0].(*run.Upgrade)
+
+	suite.Equal("billboard_top_100", step.Chart)
+	suite.Equal("post_malone_circles", step.Release)
 }
 
 func (suite *PlanTestSuite) TestNewPlanUpgradeFromDroneEvent() {
@@ -51,3 +49,15 @@ func (suite *PlanTestSuite) TestNewPlanUpgradeFromDroneEvent() {
 		suite.IsType(&run.Upgrade{}, plan.steps[0], fmt.Sprintf("for event type '%s'", event))
 	}
 }
+
+func (suite *PlanTestSuite) TestNewPlanHelpCommand() {
+	cfg := Config{
+		Command: "help",
+	}
+
+	plan, err := NewPlan(cfg)
+	suite.Require().Nil(err)
+	suite.Equal(1, len(plan.steps))
+
+	suite.Require().IsType(&run.Help{}, plan.steps[0])
+}