first version to manage sshkeys

This does not yet get autostarted, but this should already allow you to
manage your ssh keys in forgejo, and they should work...

appinfo.yml

@@ -5,6 +5,11 @@ ports:
 templatefiles:
   - src: compose.yml.j2
     dest: ~/compose.yml
+  - src: forgejo-watch-sshkeys.j2
+    dest: ~/forgejo-watch-sshkeys
+    mode: "0755"
+  - src: forgejo-watch-sshkeys.service.j2
+    dest: ~/.config/systemd/user/forgejo-watch-sshkeys.service
 exports:
   web:
     sites:

forgejo-watch-sshkeys.j2

@@ -0,0 +1,83 @@
+#!/usr/bin/python3
+
+import os
+import time
+import re
+import sys
+
+try:
+    from watchdog.observers import Observer
+    from watchdog.events import FileSystemEventHandler
+except ImportError:
+    watchdog_installed = False
+else:
+    watchdog_installed = True
+
+def rewrite_ssh_command(original_command):
+    return "/usr/bin/podman exec -i -e SSH_ORIGINAL_COMMAND -u git forgejo " + original_command
+
+def process_file(input_file_path, output_file_path):
+    with open(input_file_path, 'r') as file:
+        lines = file.readlines()
+
+    new_lines = []
+    for line in lines:
+        match = re.search(r'(command="([^"]+)")', line.strip())
+        if match:
+            original_command = match.group(2)
+            new_command = rewrite_ssh_command(original_command)
+            new_line = line.replace(original_command, new_command)
+            new_lines.append(new_line)
+        else:
+            new_lines.append(line)
+
+    with open(output_file_path, 'w') as file:
+        file.writelines(new_lines)
+
+    os.chmod(output_file_path, 0o600)
+
+def watch_file(file_to_watch, callback):
+    if watchdog_installed:
+        event_handler = FileChangeHandler(callback)
+        observer = Observer()
+        observer.schedule(event_handler, path=os.path.dirname(file_to_watch), recursive=False)
+        observer.start()
+        try:
+            while True:
+                time.sleep(3600)
+        except KeyboardInterrupt:
+            observer.stop()
+        observer.join()
+    else:
+        print("Watchdog not installed. Using polling method.  This is not optimal, please install the python module watchdog for better performance")
+        last_modified_time = os.path.getmtime(file_to_watch)
+        
+        while True:
+            current_modified_time = os.path.getmtime(file_to_watch)
+            if current_modified_time != last_modified_time:
+                print(f"{file_to_watch} has been modified. Executing callback...")
+                callback()
+                last_modified_time = current_modified_time
+            time.sleep(3)
+
+if __name__ == "__main__":
+    if os.getuid() != 0 or '_CONTAINERS_ROOTLESS_UID' not in os.environ:
+        print("This program needs to be root of your user namespace in order to have the correct permissions")
+        print("start this program with podman unshare " + sys.argv[0])
+        sys.exit(1)
+
+    input_file = "{{ homedir }}/data/git/.ssh/authorized_keys"
+    output_file = "{{ homedir }}/.ssh/authorized_keys"
+
+    output_dir = os.path.dirname(output_file)
+    if not os.path.exists(output_dir):
+        os.makedirs(output_dir)
+        os.chmod(output_dir, 0o700)
+
+    def callback_function():
+        process_file(input_file, output_file)
+
+    # ensure it is at least processed once...
+    process_file(input_file, output_file)
+
+    watch_file(input_file, callback_function)

forgejo-watch-sshkeys.service.j2

@@ -0,0 +1,13 @@
+[Unit]
+Description=Podman Compose based service
+After=network.target
+
+[Service]
+Type=exec
+# The command must be executed as "root", as the git directory is not readable by a regular user
+ExecStart=podman unshare {{ homedir }}/forgejo-watch-sshkeys
+Restart=always
+WorkingDirectory={{ homedir }}
+
+[Install]
+WantedBy=default.target