feat(cli): jb binary environment variable (#272)

Adds and environment variable TANKA_JB_PATH, to provide the location of the jb executable on the system. If unset, Tanka will search $PATH, as it did before.

cmd/tk/init.go

@@ -71,7 +71,12 @@ func initCmd() *cli.Command {
 }
 
 func installK8sLib() error {
-	if _, err := exec.LookPath("jb"); err != nil {
+	jbBinary := "jb"
+	if env := os.Getenv("TANKA_JB_PATH"); env != "" {
+		jbBinary = env
+	}
+
+	if _, err := exec.LookPath(jbBinary); err != nil {
 		return errors.New("jsonnet-bundler not found in $PATH. Follow https://tanka.dev/install#jsonnet-bundler for installation instructions")
 	}
 

docs/docs/env-vars.md

@@ -5,6 +5,11 @@ route: "/env-vars"
 
 # Environment Variables
 
+### TANKA_JB_PATH
+
+**Description**: Path to the `jb` tool executable
+**Default**: `$PATH/jb`
+
 ### TANKA_KUBECTL_PATH
 
 **Description**: Path to the `kubectl` tool executable