Add docker.github.io documentation checker and update doc message

Signed-off-by: Ulysses Souza <ulyssessouza@gmail.com>

compose/cli/main.py

@@ -310,14 +310,14 @@ class TopLevelCommand:
 
         Options:
             --resolve-image-digests  Pin image tags to digests.
-            --no-interpolate         Don't interpolate environment variables
+            --no-interpolate         Don't interpolate environment variables.
             -q, --quiet              Only validate the configuration, don't print
                                      anything.
             --services               Print the service names, one per line.
             --volumes                Print the volume names, one per line.
             --hash="*"               Print the service config hash, one per line.
                                      Set "service1,service2" for a list of specified services
-                                     or use the wildcard symbol to display all services
+                                     or use the wildcard symbol to display all services.
         """
 
         additional_options = {'--no-interpolate': options.get('--no-interpolate')}
@@ -1005,7 +1005,7 @@ class TopLevelCommand:
             --build                    Build images before starting containers.
             --abort-on-container-exit  Stops all containers if any container was
                                        stopped. Incompatible with -d.
-            --attach-dependencies      Attach to dependent containers
+            --attach-dependencies      Attach to dependent containers.
             -t, --timeout TIMEOUT      Use this timeout in seconds for container
                                        shutdown when attached or when containers are
                                        already running. (default: 10)

script/docs/check_help.py

@@ -0,0 +1,29 @@
+#!/usr/bin/env python3
+import glob
+import os.path
+import re
+import subprocess
+
+USAGE_RE = re.compile(r"```.*?\nUsage:.*?```", re.MULTILINE | re.DOTALL)
+USAGE_IN_CMD_RE = re.compile(r"^Usage:.*", re.MULTILINE | re.DOTALL)
+
+HELP_CMD = "docker run --rm docker/compose:latest %s --help"
+
+for file in glob.glob("compose/reference/*.md"):
+    with open(file) as f:
+        data = f.read()
+    if not USAGE_RE.search(data):
+        print("Not a command:", file)
+        continue
+    subcmd = os.path.basename(file).replace(".md", "")
+    if subcmd == "overview":
+        continue
+    print(f"Found {subcmd}: {file}")
+    help_cmd = HELP_CMD % subcmd
+    help = subprocess.check_output(help_cmd.split())
+    help = help.decode("utf-8")
+    help = USAGE_IN_CMD_RE.findall(help)[0]
+    help = help.strip()
+    data = USAGE_RE.sub(f"```none\n{help}\n```", data)
+    with open(file, "w") as f:
+        f.write(data)