feat: support HELMFILE_KUBE_CONTEXT env var for default kube context (#2593)

* feat: support HELMFILE_KUBE_CONTEXT env var for default kube context

Mirrors the existing HELMFILE_ENVIRONMENT pattern: the --kube-context
CLI flag takes precedence, falling back to HELMFILE_KUBE_CONTEXT when
unset.

Refs #1213.

Signed-off-by: Dominik Schmidt <dev@dominik-schmidt.de>

* docs: mention HELMFILE_KUBE_CONTEXT in cli.md and templating.md

Signed-off-by: Dominik Schmidt <dev@dominik-schmidt.de>

---------

Signed-off-by: Dominik Schmidt <dev@dominik-schmidt.de>

pkg/config/global.go

@@ -124,7 +124,17 @@ func (g *GlobalImpl) Kubeconfig() string {
 
 // KubeContext returns the name of the kubectl context to use.
 func (g *GlobalImpl) KubeContext() string {
-	return g.GlobalOptions.KubeContext
+	var kubeContext string
+
+	switch {
+	case g.GlobalOptions.KubeContext != "":
+		kubeContext = g.GlobalOptions.KubeContext
+	case os.Getenv("HELMFILE_KUBE_CONTEXT") != "":
+		kubeContext = os.Getenv("HELMFILE_KUBE_CONTEXT")
+	default:
+		kubeContext = ""
+	}
+	return kubeContext
 }
 
 // Namespace returns the namespace to use.

pkg/config/global_test.go

@@ -45,3 +45,40 @@ func TestFileOrDir(t *testing.T) {
 	}
 	os.Unsetenv(envvar.FilePath)
 }
+
+// TestKubeContext tests the kube-context flag and HELMFILE_KUBE_CONTEXT env var fallback
+func TestKubeContext(t *testing.T) {
+	tests := []struct {
+		opts     GlobalOptions
+		env      string
+		expected string
+	}{
+		{
+			opts:     GlobalOptions{},
+			env:      "",
+			expected: "",
+		},
+		{
+			opts:     GlobalOptions{},
+			env:      "envset",
+			expected: "envset",
+		},
+		{
+			opts:     GlobalOptions{KubeContext: "flagset"},
+			env:      "",
+			expected: "flagset",
+		},
+		{
+			opts:     GlobalOptions{KubeContext: "flagset"},
+			env:      "envset",
+			expected: "flagset",
+		},
+	}
+
+	for _, test := range tests {
+		os.Setenv(envvar.KubeContext, test.env)
+		received := NewGlobalImpl(&test.opts).KubeContext()
+		require.Equalf(t, test.expected, received, "KubeContext expected %s, received %s", test.expected, received)
+	}
+	os.Unsetenv(envvar.KubeContext)
+}

pkg/envvar/const.go

@@ -9,6 +9,7 @@ const (
 	DisableRunnerUniqueID = "HELMFILE_DISABLE_RUNNER_UNIQUE_ID"
 	Experimental          = "HELMFILE_EXPERIMENTAL" // environment variable for experimental features, expecting "true" lower case
 	Environment           = "HELMFILE_ENVIRONMENT"
+	KubeContext           = "HELMFILE_KUBE_CONTEXT"
 	FilePath              = "HELMFILE_FILE_PATH"
 	TempDir               = "HELMFILE_TEMPDIR"
 	UpgradeNoticeDisabled = "HELMFILE_UPGRADE_NOTICE_DISABLED"