Add config template generation

shepherd/core.py

@@ -1,5 +1,5 @@
 """
-Core shepherd module, tying together main service functionality.
+Core shepherd module, tying together main service functionality. Provides main CLI.
 """
 
 
@@ -41,7 +41,10 @@ def cli(ctx, default_config_path, local_operation, only_default_layer):
     ending with ".toml" will be used.
     """
     version_text = pkg_resources.get_distribution("shepherd")
-    log.info(F"Initialising Shepherd Agent {version_text}")
+    log.info(F"Shepherd Agent {version_text}")
+
+    if ctx.invoked_subcommand == "template":
+        return
 
     if not default_config_path:
         default_config_path = sorted(glob.glob("./shepherd*.toml"))[:1]
@@ -91,6 +94,81 @@ def test():
     print("test!")
 
 
+@cli.command()
+@click.argument('plugin_name', required=False)
+@click.option('-a', '--include-all', is_flag=True,
+              help="Include all optional fields in the template")
+@click.option('-c', '--config', 'config_path',  type=click.Path(),
+              help="Path to append or create config tempalate")
+@click.option('-d', '--plugin-dir', type=click.Path(),
+              help="Directory to search for plugin modules, in addition to built in Shepherd"
+              " plugins and the global import path. Defaults to current directory.")
+@click.pass_context
+def template(ctx, plugin_name, include_all, config_path, plugin_dir):
+    """
+    Generate a template config TOML file for PLUGIN, or for the Shepherd core if
+    PLUGIN is not provided.
+
+    If config path is provided ("-c"), append to that file (if it exists) or write to
+    a new file (if it doesn't yet exist).
+    """
+
+    if not plugin_dir:
+        plugin_dir = Path.cwd()
+
+    confspec = ConfigSpecification()
+    if (not plugin_name) or (plugin_name=="shepherd"):
+        plugin_name = "shepherd"
+        define_core_config(confspec)
+    else:
+        try:
+            plugin_class = plugin.find_plugins([plugin_name], plugin_dir)[0]
+        except plugin.PluginLoadError as e:
+            log.error(e.args[0])
+            sys.exit(1)
+        plugin_class.define_config(confspec)
+
+    template_dict = confspec.get_template(include_all)
+    template_toml = toml.dumps({plugin_name: template_dict})
+
+    log.info(F"Config template for [{plugin_name}]: \n\n"+template_toml)
+
+    if not config_path:
+        # reuse parent "-c" for convenience
+        config_path = ctx.parent.params["default_config_path"]
+
+    if not config_path:
+        return
+
+    if Path(config_path).is_file():
+        try:
+            existing_config = toml.load(config_path)
+        except Exception:
+            click.confirm(
+                F"File {config_path} already exists and is not a valid TOML file. Overwrite?",
+                default=True, abort=True)
+
+            click.echo(F"Writing [{plugin_name}] template to {config_path}")
+            with open(config_path, 'w+') as f:
+                f.write(template_toml)
+        else:
+            if plugin_name in existing_config:
+                click.confirm(F"Overwrite [{plugin_name}] section in {config_path}?",
+                              default=True, abort=True)
+                click.echo(F"Overwriting [{plugin_name}] section in {config_path}")
+            else:
+                click.confirm(F"Add [{plugin_name}] section to {config_path}?",
+                              default=True, abort=True)
+                click.echo(F"Adding [{plugin_name}] section to {config_path}")
+            existing_config[plugin_name] = template_dict
+            with open(config_path, 'w+') as f:
+                f.write(toml.dumps(existing_config))
+    else:
+        click.echo(F"Writing [{plugin_name}] template to {config_path}")
+        with open(config_path, 'w+') as f:
+            f.write(template_toml)
+
+
 def compile_config_and_get_plugins(confman, default_config_path, layers_disabled):
     """
     Run through the process of assembling the various config layers, falling back to working

shepherd/plugin.py

@@ -12,6 +12,10 @@ import os
 import shepherd.scheduler
 
 
+class PluginLoadError(Exception):
+    pass
+
+
 class Hook():
     def __init__(self):
         self.attached_functions = []
@@ -242,17 +246,17 @@ def find_plugins(plugin_names, plugin_dir=None):
             # that can't be found
         except ModuleNotFoundError:
             try:
-                if (plugin_dir is not None) and (plugin_dir != ""):
+                if plugin_dir:
                     if os.path.isdir(plugin_dir):
                         sys.path.append(plugin_dir)
                         mod = importlib.import_module("shepherd_" + plugin_name)
                         sys.path.remove(plugin_dir)
                     else:
-                        raise Exception("plugin_dir is not a valid directory")
+                        raise PluginLoadError("plugin_dir is not a valid directory")
                 else:
                     mod = importlib.import_module("shepherd_" + plugin_name)
             except ModuleNotFoundError:
-                raise Exception("Could not find plugin "+plugin_name)
+                raise PluginLoadError("Could not find plugin "+plugin_name)
 
         # Scan imported module for Plugin subclass
         attrs = [getattr(mod, name) for name in dir(mod)]
@@ -262,7 +266,7 @@ def find_plugins(plugin_names, plugin_dir=None):
                     plugin_classes[plugin_name] = attr
                     break
         else:
-            raise Exception("Imported shepherd plugin modules must contain a "
+            raise PluginLoadError("Imported shepherd plugin modules must contain a "
                                   "subclass of shepherd.plugin.Plugin, such as"
                                   "shepherd.plugin.SimplePlugin")