DEVOPS-2496 add max history setting (#12)

* add history_max setting

* update docs

* use suite for env test

internal/env/config.go

@@ -10,6 +10,10 @@ import (
 	"github.com/kelseyhightower/envconfig"
 )
 
+const (
+	DefaultHistoryMax = 10
+)
+
 var (
 	justNumbers    = regexp.MustCompile(`^\d+$`)
 	deprecatedVars = []string{"PURGE", "RECREATE_PODS", "TILLER_NS", "UPGRADE", "CANARY_IMAGE", "CLIENT_ONLY", "STABLE_REPO_URL"}
@@ -45,6 +49,7 @@ type Config struct {
 	Wait               bool     `envconfig:"wait_for_upgrade"`       // Pass --wait to applicable helm commands
 	ReuseValues        bool     `split_words:"true"`                 // Pass --reuse-values to `helm upgrade`
 	KeepHistory        bool     `split_words:"true"`                 // Pass --keep-history to `helm uninstall`
+	HistoryMax         int      `split_words:"true"`                 // Pass --history-max option
 	Timeout            string   ``                                   // Argument to pass to --timeout in applicable helm commands
 	Chart              string   ``                                   // Chart argument to use in applicable helm commands
 	Release            string   ``                                   // Release argument to use in applicable helm commands
@@ -79,6 +84,9 @@ func NewConfig(stdout, stderr io.Writer) (*Config, error) {
 		KubeToken:      aliases.KubeToken,
 		Certificate:    aliases.Certificate,
 
+		// set to same default as helm CLI
+		HistoryMax: DefaultHistoryMax,
+
 		Stdout: stdout,
 		Stderr: stderr,
 	}

internal/env/config_test.go

@@ -217,6 +217,15 @@ func (suite *ConfigTestSuite) TestValuesSecretsWithDebugLogging() {
 	suite.Contains(stderr.String(), `$SECRET_WATER not present in environment, replaced with ""`)
 }
 
+func (suite *ConfigTestSuite) TestHistoryMax() {
+	conf := NewTestConfig(suite.T())
+	suite.Assert().Equal(10, conf.HistoryMax)
+
+	suite.setenv("PLUGIN_HISTORY_MAX", "0")
+	conf = NewTestConfig(suite.T())
+	suite.Assert().Equal(0, conf.HistoryMax)
+}
+
 func (suite *ConfigTestSuite) setenv(key, val string) {
 	orig, ok := os.LookupEnv(key)
 	if ok {

internal/env/testing.go

@@ -0,0 +1,15 @@
+package env
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func NewTestConfig(t *testing.T) *Config {
+	conf, err := NewConfig(os.Stdout, os.Stderr)
+	require.NoError(t, err)
+
+	return conf
+}