add --no-render-dir flag to disable writing config to disk.

components/hab/src/cli.rs

@@ -577,6 +577,7 @@ pub fn get() -> App<'static, 'static> {
                 (@arg MOCK_DATA: -m --("mock-data") +takes_value "Path to json file with mock data for template, defaults to none")
                 (@arg PRINT: -p --("print") "Prints config to STDOUT")
                 (@arg RENDER_DIR: -r --("render-dir") +takes_value "Path to render templates to, defaults to ./results/")
+                (@arg NO_WRITE_FILE: -n --("no-render") --("no-render-dir") "Don't write anything to disk, ignores --render-dir")
             )
         )
         (@subcommand ring =>

components/hab/src/command/plan/render.rs

@@ -30,6 +30,7 @@ pub fn start(
     user_toml_path: Option<String>,
     mock_data_path: Option<String>,
     print: bool,
+    no_render_dir: bool,
     render_dir: String,
 ) -> Result<()> {
     // Strip the file name out of our passed template
@@ -102,8 +103,11 @@ pub fn start(
         ui.warn(format!("========### End rendered template: {}", &template_path))?;
     }
 
-    // Render our template file
-    create_with_template(ui, &format!("{}/{}", render_dir, file_name), &rendered_template)?;
+    if !(no_render_dir) {
+      // Render our template file
+      create_with_template(ui, &format!("{}/{}", render_dir, file_name), &rendered_template)?;
+    }
+
     ui.br()?;
     // not really sure this is correct...
     Ok(())

components/hab/src/main.rs

@@ -676,6 +676,7 @@ fn sub_plan_render(ui: &mut UI, m: &ArgMatches<'_>) -> Result<()> {
     };
 
     let print = m.is_present("PRINT");
+    let no_render_dir = m.is_present("NO_WRITE_FILE");
 
     let render_dir = match m.value_of("RENDER_DIR") {
         Some(name) => name.to_string(),
@@ -689,6 +690,7 @@ fn sub_plan_render(ui: &mut UI, m: &ArgMatches<'_>) -> Result<()> {
       user_toml_path,
       mock_data_path,
       print,
+      no_render_dir,
       render_dir,
     )
 }