Support execution of additional commands during ct lint (#283)

* support execution of additional commands for lint

Given that helm unittest is installed locally or mounted into the chart
testing container one could use this to run helm unittest for each
chart.

```
additional-commands:
 - helm unittest --helm3 -f tests/*.yaml {{ .Path }}
```

The command is treated as a go template. Like this it's possible to get
the path to the chart as in the example. It would also be open for
further extension if needed.

Signed-off-by: Torsten Walter <mail@torstenwalter.de>

* Use sh to execute command

Signed-off-by: Torsten Walter <mail@torstenwalter.de>

Co-authored-by: Reinhard Nägele <unguiculus@gmail.com>

* rename function to NewCmdTemplateExecutor

Signed-off-by: Torsten Walter <mail@torstenwalter.de>

* add error handling

Signed-off-by: Torsten Walter <mail@torstenwalter.de>

* add documentation

Signed-off-by: Torsten Walter <mail@torstenwalter.de>

* use go-shellwords to split rendered command

Signed-off-by: Torsten Walter <mail@torstenwalter.de>

* Update pkg/tool/cmdexecutor.go

Signed-off-by: Torsten Walter <mail@torstenwalter.de>

Co-authored-by: Reinhard Nägele <unguiculus@gmail.com>

* add unit tests

Signed-off-by: Torsten Walter <mail@torstenwalter.de>

Co-authored-by: Reinhard Nägele <unguiculus@gmail.com>

pkg/chart/chart.go

@@ -131,6 +131,13 @@ type Linter interface {
 	Yamale(yamlFile string, schemaFile string) error
 }
 
+// CmdExecutor is the interface
+//
+// RunCommand renders cmdTemplate as go template using data and executes the resulting command
+type CmdExecutor interface {
+	RunCommand(cmdTemplate string, data interface{}) error
+}
+
 // DirectoryLister is the interface
 //
 // ListChildDirs lists direct child directories of parentDir given they pass the test function
@@ -224,6 +231,7 @@ type Testing struct {
 	kubectl                  Kubectl
 	git                      Git
 	linter                   Linter
+	cmdExecutor              CmdExecutor
 	accountValidator         AccountValidator
 	directoryLister          DirectoryLister
 	chartUtils               ChartUtils
@@ -253,6 +261,7 @@ func NewTesting(config config.Configuration) (Testing, error) {
 		git:              tool.NewGit(procExec),
 		kubectl:          tool.NewKubectl(procExec),
 		linter:           tool.NewLinter(procExec),
+		cmdExecutor:      tool.NewCmdTemplateExecutor(procExec),
 		accountValidator: tool.AccountValidator{},
 		directoryLister:  util.DirectoryLister{},
 		chartUtils:       util.ChartUtils{},
@@ -451,6 +460,13 @@ func (t *Testing) LintChart(chart *Chart) TestResult {
 		}
 	}
 
+	for _, cmd := range t.config.AdditionalCommands {
+		if err := t.cmdExecutor.RunCommand(cmd, chart); err != nil {
+			result.Error = err
+			return result
+		}
+	}
+
 	// Lint with defaults if no values files are specified.
 	if len(valuesFiles) == 0 {
 		valuesFiles = append(valuesFiles, "")

pkg/chart/chart_test.go

@@ -109,6 +109,15 @@ func (h fakeHelm) Version() (string, error) {
 	return "v3.0.0", nil
 }
 
+type fakeCmdExecutor struct {
+	mock.Mock
+}
+
+func (c *fakeCmdExecutor) RunCommand(cmdTemplate string, data interface{}) error {
+	c.Called(cmdTemplate, data)
+	return nil
+}
+
 var ct Testing
 
 func init() {
@@ -417,3 +426,47 @@ func TestChart_HasCIValuesFile(t *testing.T) {
 		})
 	}
 }
+
+func TestChart_AdditionalCommandsAreRun(t *testing.T) {
+	type testData struct {
+		name            string
+		cfg             config.Configuration
+		callsRunCommand int
+	}
+
+	testCases := []testData{
+		{
+			name:            "no additional commands",
+			cfg:             config.Configuration{},
+			callsRunCommand: 0,
+		},
+		{
+			name: "one command",
+			cfg: config.Configuration{
+				AdditionalCommands: []string{"helm unittest --helm3 -f tests/*.yaml {{ .Path }}"},
+			},
+			callsRunCommand: 1,
+		},
+		{
+			name: "multiple commands",
+			cfg: config.Configuration{
+				AdditionalCommands: []string{"echo", "helm unittest --helm3 -f tests/*.yaml {{ .Path }}"},
+			},
+			callsRunCommand: 2,
+		},
+	}
+
+	for _, testData := range testCases {
+		t.Run(testData.name, func(t *testing.T) {
+			fakeCmdExecutor := new(fakeCmdExecutor)
+			fakeCmdExecutor.On("RunCommand", mock.Anything, mock.Anything).Return(nil)
+
+			ct := newTestingMock(testData.cfg)
+			ct.cmdExecutor = fakeCmdExecutor
+
+			ct.LintChart(&Chart{})
+
+			fakeCmdExecutor.AssertNumberOfCalls(t, "RunCommand", testData.callsRunCommand)
+		})
+	}
+}

pkg/config/config.go

@@ -50,6 +50,7 @@ type Configuration struct {
 	ValidateMaintainers   bool     `mapstructure:"validate-maintainers"`
 	ValidateChartSchema   bool     `mapstructure:"validate-chart-schema"`
 	ValidateYaml          bool     `mapstructure:"validate-yaml"`
+	AdditionalCommands    []string `mapstructure:"additional-commands"`
 	CheckVersionIncrement bool     `mapstructure:"check-version-increment"`
 	ProcessAllCharts      bool     `mapstructure:"all"`
 	Charts                []string `mapstructure:"charts"`

pkg/tool/cmdexecutor.go

@@ -0,0 +1,38 @@
+package tool
+
+import (
+	"strings"
+	"text/template"
+
+	"github.com/mattn/go-shellwords"
+)
+
+type ProcessExecutor interface {
+	RunProcess(executable string, execArgs ...interface{}) error
+}
+
+type CmdTemplateExecutor struct {
+	exec ProcessExecutor
+}
+
+func NewCmdTemplateExecutor(exec ProcessExecutor) CmdTemplateExecutor {
+	return CmdTemplateExecutor{
+		exec: exec,
+	}
+}
+
+func (t CmdTemplateExecutor) RunCommand(cmdTemplate string, data interface{}) error {
+	var template = template.Must(template.New("command").Parse(cmdTemplate))
+	var b strings.Builder
+	if err := template.Execute(&b, data); err != nil {
+		return err
+	}
+	rendered := b.String()
+
+	words, err := shellwords.Parse(rendered)
+	if err != nil {
+		return err
+	}
+	name, args := words[0], words[1:]
+	return t.exec.RunProcess(name, args)
+}

pkg/tool/cmdexecutor_test.go

@@ -0,0 +1,76 @@
+package tool
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/mock"
+)
+
+type fakeProcessExecutor struct {
+	mock.Mock
+}
+
+func (c *fakeProcessExecutor) RunProcess(executable string, execArgs ...interface{}) error {
+	c.Called(executable, execArgs[0])
+	return nil
+}
+
+func TestCmdTemplateExecutor_RunCommand(t *testing.T) {
+	type args struct {
+		cmdTemplate string
+		data        interface{}
+	}
+	tests := []struct {
+		name     string
+		args     args
+		wantErr  bool
+		validate func(t *testing.T, executor *fakeProcessExecutor)
+	}{
+		{
+			name: "command without arguments",
+			args: args{
+				cmdTemplate: "echo",
+				data:        nil,
+			},
+			validate: func(t *testing.T, executor *fakeProcessExecutor) {
+				executor.AssertCalled(t, "RunProcess", "echo", []string{})
+			},
+			wantErr: false,
+		},
+		{
+			name: "command with args",
+			args: args{
+				cmdTemplate: "echo hello world",
+			},
+			validate: func(t *testing.T, executor *fakeProcessExecutor) {
+				executor.AssertCalled(t, "RunProcess", "echo", []string{"hello", "world"})
+			},
+			wantErr: false,
+		},
+		{
+			name: "interpolate args",
+			args: args{
+				cmdTemplate: "helm unittest --helm3 -f tests/*.yaml {{ .Path }}",
+				data:        map[string]string{"Path": "charts/my-chart"},
+			},
+			validate: func(t *testing.T, executor *fakeProcessExecutor) {
+				executor.AssertCalled(t, "RunProcess", "helm", []string{"unittest", "--helm3", "-f", "tests/*.yaml", "charts/my-chart"})
+			},
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			processExecutor := new(fakeProcessExecutor)
+			processExecutor.On("RunProcess", mock.Anything, mock.Anything).Return(nil)
+			templateExecutor := CmdTemplateExecutor{
+				exec: processExecutor,
+			}
+			if err := templateExecutor.RunCommand(tt.args.cmdTemplate, tt.args.data); (err != nil) != tt.wantErr {
+				t.Errorf("RunCommand() error = %v, wantErr %v", err, tt.wantErr)
+			}
+			tt.validate(t, processExecutor)
+
+		})
+	}
+}