add '--config-create' command-line option

(#2333)

docs/options.md

@@ -76,6 +76,7 @@
     -c, --config FILE           Additional configuration files
     --config-yaml FILE          Additional configuration files in YAML format
     --config-toml FILE          Additional configuration files in TOML format
+    --config-create             Create a basic configuration file
     --config-ignore             Do not read default configuration files
 
 ## Authentication Options:

gallery_dl/__init__.py

@@ -38,7 +38,7 @@ def main():
         log = output.initialize_logging(args.loglevel)
 
         # configuration
-        if args.load_config:
+        if args.config_load:
             config.load()
         if args.configs_json:
             config.load(args.configs_json, strict=True)
@@ -218,6 +218,10 @@ def main():
                     "Deleted %d %s from '%s'",
                     cnt, "entry" if cnt == 1 else "entries", cache._path(),
                 )
+
+        elif args.config_init:
+            return config.initialize()
+
         else:
             if not args.urls and not args.inputfiles:
                 parser.error(

gallery_dl/config.py

@@ -49,6 +49,47 @@ if util.EXECUTABLE:
 # --------------------------------------------------------------------
 # public interface
 
+
+def initialize():
+    paths = list(map(util.expand_path, _default_configs))
+
+    for path in paths:
+        if os.access(path, os.R_OK | os.W_OK):
+            log.error("There is already a configuration file at '%s'", path)
+            return 1
+
+    for path in paths:
+        try:
+            os.makedirs(os.path.dirname(path), exist_ok=True)
+            with open(path, "x", encoding="utf-8") as fp:
+                fp.write("""\
+{
+    "extractor": {
+
+    },
+    "downloader": {
+
+    },
+    "output": {
+
+    },
+    "postprocessor": {
+
+    }
+}
+""")
+            break
+        except OSError as exc:
+            log.debug("%s: %s", exc.__class__.__name__, exc)
+    else:
+        log.error("Unable to create a new configuration file "
+                  "at any of the default paths")
+        return 1
+
+    log.info("Created a basic configuration file at '%s'", path)
+    return 0
+
+
 def load(files=None, strict=False, load=util.json_loads):
     """Load JSON configuration files"""
     for pathfmt in files or _default_configs:

gallery_dl/option.py

@@ -341,14 +341,19 @@ def build_parser():
         dest="configs_toml", metavar="FILE", action="append",
         help="Additional configuration files in TOML format",
     )
+    configuration.add_argument(
+        "--config-create",
+        dest="config_init", action="store_true",
+        help="Create a basic configuration file",
+    )
     configuration.add_argument(
         "--config-ignore",
-        dest="load_config", action="store_false",
+        dest="config_load", action="store_false",
         help="Do not read default configuration files",
     )
     configuration.add_argument(
         "--ignore-config",
-        dest="load_config", action="store_false",
+        dest="config_load", action="store_false",
         help=argparse.SUPPRESS,
     )