Trigger pull explictly if needed (#184)

fixes #179

The pull option was set as the default that will cause to download the latest version when it is available, which is not desired as discussed in #179. In most cases, users want to keep on using the image they pulled in the first place. The new version of image download has better happened when explicitly triggered by setting pull.

This commit first makes --no-pull the default of --pull/no-pull option. The pull logic tweaks a bit so that when the image does not exist, it will anyway trigger the pull. If the image exists, the --pull needs to be set to trigger the pull.

Author: unkcpz

aiidalab_launch/__main__.py

@@ -336,14 +336,19 @@ async def _async_start(
             )
 
     # Obtain image (either via pull or local).
-    if pull:
-        msg = (
-            f"Downloading image '{instance.profile.image}', this may take a while..."
-            if instance.image is None
-            else f"Downloading latest version of '{instance.profile.image}'..."
-        )
+    if instance.image is None:
+        # always pull if no image is available
+        msg = f"Downloading image '{profile.image}', this may take a while..."
+        with spinner(msg):
+            instance.pull()
+    elif pull:
+        # pull if explicitly requested and pull latest version of image
+        msg = f"Downloading latest version of '{profile.image}'..."
         with spinner(msg):
             instance.pull()
+    else:
+        # use local image
+        msg = f"Using local image '{profile.image}'."
 
     if instance.image is None:
         raise click.ClickException(
@@ -506,7 +511,7 @@ async def _async_start(
 )
 @click.option(
     "--pull/--no-pull",
-    default=True,
+    default=False,
     help=(
         "Specify whether to pull the configured image prior to the first start "
         "of the container."