From 10d4d2ed999a403e2464f673e0e19b95ee4e1ac6 Mon Sep 17 00:00:00 2001
From: rudeigerc <rudeigerc@gmail.com>
Date: Sat, 22 Aug 2020 02:30:22 +0800
Subject: [PATCH 1/2] feat(env): add support of accepting a specific variable
 for helm env

Signed-off-by: Yuchen Cheng <rudeigerc@gmail.com>
---
 cmd/helm/env.go                       | 48 +++++++++++++++++++--------
 cmd/helm/env_test.go                  |  9 +++++
 cmd/helm/testdata/output/env-comp.txt | 16 +++++++++
 3 files changed, 59 insertions(+), 14 deletions(-)
 create mode 100644 cmd/helm/testdata/output/env-comp.txt

diff --git a/cmd/helm/env.go b/cmd/helm/env.go
index 4db3d80de..3754b748d 100644
--- a/cmd/helm/env.go
+++ b/cmd/helm/env.go
@@ -32,25 +32,45 @@ Env prints out all the environment information in use by Helm.
 
 func newEnvCmd(out io.Writer) *cobra.Command {
 	cmd := &cobra.Command{
-		Use:               "env",
-		Short:             "helm client environment information",
-		Long:              envHelp,
-		Args:              require.NoArgs,
-		ValidArgsFunction: noCompletions,
+		Use:   "env",
+		Short: "helm client environment information",
+		Long:  envHelp,
+		Args:  require.MaximumNArgs(1),
+		ValidArgsFunction: func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+			if len(args) == 0 {
+				keys := getSortedEnvVarKeys()
+				return keys, cobra.ShellCompDirectiveNoFileComp
+			}
+
+			return nil, cobra.ShellCompDirectiveNoFileComp
+		},
 		Run: func(cmd *cobra.Command, args []string) {
 			envVars := settings.EnvVars()
 
-			// Sort the variables by alphabetical order.
-			// This allows for a constant output across calls to 'helm env'.
-			var keys []string
-			for k := range envVars {
-				keys = append(keys, k)
-			}
-			sort.Strings(keys)
-			for _, k := range keys {
-				fmt.Fprintf(out, "%s=\"%s\"\n", k, envVars[k])
+			if len(args) == 0 {
+				// Sort the variables by alphabetical order.
+				// This allows for a constant output across calls to 'helm env'.
+				keys := getSortedEnvVarKeys()
+
+				for _, k := range keys {
+					fmt.Fprintf(out, "%s=\"%s\"\n", k, envVars[k])
+				}
+			} else {
+				fmt.Fprintf(out, "%s\n", envVars[args[0]])
 			}
 		},
 	}
 	return cmd
 }
+
+func getSortedEnvVarKeys() []string {
+	envVars := settings.EnvVars()
+
+	var keys []string
+	for k := range envVars {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+
+	return keys
+}
diff --git a/cmd/helm/env_test.go b/cmd/helm/env_test.go
index a7170a8cc..abdc9c94e 100644
--- a/cmd/helm/env_test.go
+++ b/cmd/helm/env_test.go
@@ -20,6 +20,15 @@ import (
 	"testing"
 )
 
+func TestEnv(t *testing.T) {
+	tests := []cmdTestCase{{
+		name:   "completion for env",
+		cmd:    "__complete env ''",
+		golden: "output/env-comp.txt",
+	}}
+	runTestCmd(t, tests)
+}
+
 func TestEnvFileCompletion(t *testing.T) {
 	checkFileCompletion(t, "env", false)
 }
diff --git a/cmd/helm/testdata/output/env-comp.txt b/cmd/helm/testdata/output/env-comp.txt
new file mode 100644
index 000000000..c4b46ae6b
--- /dev/null
+++ b/cmd/helm/testdata/output/env-comp.txt
@@ -0,0 +1,16 @@
+HELM_BIN
+HELM_CACHE_HOME
+HELM_CONFIG_HOME
+HELM_DATA_HOME
+HELM_DEBUG
+HELM_KUBEAPISERVER
+HELM_KUBECONTEXT
+HELM_KUBETOKEN
+HELM_MAX_HISTORY
+HELM_NAMESPACE
+HELM_PLUGINS
+HELM_REGISTRY_CONFIG
+HELM_REPOSITORY_CACHE
+HELM_REPOSITORY_CONFIG
+:4
+Completion ended with directive: ShellCompDirectiveNoFileComp

From 195d7a650712d8eee2db887bf8e1a4e2c363328b Mon Sep 17 00:00:00 2001
From: Yuchen Cheng <rudeigerc@gmail.com>
Date: Sat, 22 Aug 2020 22:04:09 +0800
Subject: [PATCH 2/2] add checkFileCompletion for env HELM_BIN

Signed-off-by: Yuchen Cheng <rudeigerc@gmail.com>
---
 cmd/helm/env_test.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/cmd/helm/env_test.go b/cmd/helm/env_test.go
index abdc9c94e..01ef25933 100644
--- a/cmd/helm/env_test.go
+++ b/cmd/helm/env_test.go
@@ -31,4 +31,5 @@ func TestEnv(t *testing.T) {
 
 func TestEnvFileCompletion(t *testing.T) {
 	checkFileCompletion(t, "env", false)
+	checkFileCompletion(t, "env HELM_BIN", false)
 }