feat: enable export_compose module to return changed state

using the digest function specified by module_utils, we can do a hash comparison if the dest file already exists and return a little extra signal (the written dest) from get_compose_image to determine if we changed or not

plugins/module_utils/weldrapiv1.py

@@ -1,10 +1,12 @@
 #
 # (c) 2022, Adam Miller ([email protected])
 # GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+import hashlib
 import json
 import os
 import shutil
 import socket  # noqa E402
+from pathlib import Path
 
 from ansible.module_utils._text import to_bytes
 from ansible.module_utils.six.moves.urllib.parse import quote
@@ -368,7 +370,7 @@ def get_compose_failed(self):
         results = json.load(self.weldr.request.open("GET", "http://localhost/api/v1/compose/failed"))
         return results
 
-    def get_compose_image(self, compose_uuid, dest):
+    def get_compose_image(self, compose_uuid, dest, digest_function):
         """
         # api.router.GET("/api/v:version/compose/image/:uuid", api.composeImageHandler)
         """
@@ -378,11 +380,20 @@ def get_compose_image(self, compose_uuid, dest):
             method="GET",
             unix_socket=self.weldr.unix_socket,
         )
+
+        if Path(dest).exists():
+            # Check if we need to overwrite
+            tmpdigest = digest_function(tmpfile)
+            destdigest = digest_function(dest)
+            if tmpdigest == destdigest:
+                os.remove(tmpfile)
+                return None
+
         shutil.copy(tmpfile, dest)
         with open(dest) as fd:
             os.fsync(fd)
         os.remove(tmpfile)
-        return None
+        return dest
 
     def get_compose_metadata(self, compose_uuid):
         """

plugins/modules/export_compose.py

@@ -53,6 +53,7 @@
 
 
 def main():
+    changed: bool = False
     module = AnsibleModule(
         argument_spec=dict(
             compose_id=dict(type="str", required=True),
@@ -62,12 +63,16 @@ def main():
 
     weldr = Weldr(module)
 
-    weldr.api.get_compose_image(
+    filepath = weldr.api.get_compose_image(
         module.params["compose_id"],
         module.params["dest"],
+        module.digest_from_file,
     )
+    if filepath is not None:
+        changed: bool = True
 
-    module.exit_json(msg="Exported compose payload to %s" % module.params["dest"])
+    module.exit_json(msg="Exported compose payload to %s" % module.params["dest"],
+                     changed=changed)
 
 
 if __name__ == "__main__":