Implement weectl daemon install --type=systemd

bin/weecfg/daemon_config.py

@@ -5,13 +5,77 @@
 #
 """Install or uninstall files necessary to run as a daemon"""
 
+import importlib.resources
+import os.path
 
-def daemon_install(daemon_type=None):
+import weecfg
+from weeutil.weeutil import bcolors
+
+
+def daemon_install(daemon_type, config_path=None, user=None, weewxd_path=None, daemon_dir=None):
     """Install the daemon files.
 
     Args:
-        daemon_type(str): The type of daemon file. Can be either 'sysv' or 'systemd'.
+        daemon_type(str): The type of daemon file. Can be either 'sysv' or 'systemd'. Required.
+        config_path(str): Path to the weewx configuration file. Default is to find it in
+            the "usual places."
+        user(str): The user to run as. Default is 'root'
+        weewxd_path(str): Path to the weewxd executable. Default is to figure it out.
+        daemon_dir(str): The directory into which the finished daemon file should be put. If
+            not given, it will be determined on the basis of daemon_type.
     """
+    config_path, config_dict = weecfg.read_config(config_path)
+
+    print(f"The configuration file {bcolors.BOLD}{config_path}{bcolors.ENDC} will be used.")
+
+    if not weewxd_path:
+        # Find it by importing weewxd.py
+        import weewxd
+        weewxd_path = weewxd.__file__
+
+    if daemon_type == 'systemd':
+        install_systemd(config_path=config_path,
+                        user=user,
+                        weewxd_path=weewxd_path,
+                        daemon_dir=daemon_dir)
+    elif daemon_type == 'sysv':
+        """To appear"""
+    else:
+        raise ValueError(f"Unknown daemon type: {daemon_type}")
+
+
+def install_systemd(config_path=None, user=None, weewxd_path=None, daemon_dir=None):
+    """Install a systemd file."""
+
+    service_file_name = 'weewx.service'
+
+    # Get the systemd template from package resources.
+    with importlib.resources.path('wee_resources', 'util') as util_path:
+        systemd_template_path = os.path.join(util_path, 'systemd', service_file_name)
+        # Read it all in.
+        with open(systemd_template_path, 'rt') as fd:
+            in_lines = fd.readlines()
+
+    # Process it line by line, making any necessary substitutions
+    out_lines = []
+    for line in in_lines:
+        if '=' in line:
+            key, value = line.split('=')
+            if user and 'User' in key:
+                line = f'User={user}\n'
+            elif 'ExecStart' in key:
+                line = f'ExecStart={weewxd_path} {config_path}\n'
+        out_lines.append(line)
+
+    # Figure out where the finished systemd file will go.
+    if not daemon_dir:
+        # No idea if this is true of all systemd systems. Probably not.
+        daemon_dir = '/etc/systemd/system'
+    target_path = os.path.join(daemon_dir, service_file_name)
+
+    with open(target_path, 'w') as outd:
+        outd.writelines(out_lines)
+    print(f"Systemd file written to {bcolors.BOLD}{target_path}{bcolors.ENDC}")
 
 
 def daemon_uninstall(daemon_type=None):

bin/weectllib/parse_daemon.py

@@ -8,7 +8,8 @@ import weecfg.daemon_config
 from weeutil.weeutil import bcolors
 
 daemon_install_usage = f"""{bcolors.BOLD}weectl daemon install --type={{sysv|systemd}} 
-            [--config=CONFIG-PATH]{bcolors.ENDC}"""
+            [--config=CONFIG-PATH] [--user=USER] 
+            [--weewxd-path=WEEWXD-PATH] [-daemon-dir=DAEMON-DIR] {bcolors.ENDC}"""
 daemon_uninstall_usage = f"""{bcolors.BOLD}weectl daemon uninstall  --type={{sysv|systemd}} 
             [--config=CONFIG-PATH]{bcolors.ENDC}"""
 
@@ -40,7 +41,18 @@ def add_subparser(subparsers):
                                        dest="daemon_type",
                                        required=True,
                                        help="Type of file to install. Required.")
-
+    daemon_install_parser.add_argument('--config',
+                                       metavar='CONFIG-PATH',
+                                       help=f'Path to configuration file. '
+                                            f'Default is "{weecfg.default_config_path}".')
+    daemon_install_parser.add_argument('--user',
+                                       help='Run as USER. If not given, "root" will be used.')
+    daemon_install_parser.add_argument('--weewxd-path',
+                                       help='Path to the weewxd.py file. If not given, it will '
+                                            'be inferred')
+    daemon_install_parser.add_argument('--daemon-dir',
+                                       help='Path to the directory in which the finished daemon '
+                                            'file should be put.')
     daemon_install_parser.set_defaults(func=daemon_install)
 
     # ---------- Action 'uninstall' ----------
@@ -60,7 +72,11 @@ def add_subparser(subparsers):
 
 
 def daemon_install(namespace):
-    weecfg.daemon_config.daemon_install(namespace.daemon_type)
+    weecfg.daemon_config.daemon_install(namespace.daemon_type,
+                                        config_path=namespace.config,
+                                        user=namespace.user,
+                                        weewxd_path=namespace.weewxd_path,
+                                        daemon_dir=namespace.daemon_dir)
 
 
 def daemon_uninstall(namespace):