Add a facility to warn users of versions with known issues. (#1958)

This change was prompted by the recent issue we had with version
20180105, where an issue was discovered, but we did not have a
good means of notifying users about the issue.

With this change, the CLI will download a versions info file from
https://storage.googleapis.com/cloud-datalab/version-issues.js
that contains a JSON object reporting known issues for any
affected versions of the CLI. It will then check the current
version against that object and report any matching warnings.

Author: ojarjur

tools/cli/commands/utils.py

@@ -368,6 +368,18 @@ def maybe_prompt_for_zone(args, gcloud_compute, instance):
     return
 
 
+def print_warning_messages(args):
+    """Return whether or not warning messages should be printed.
+
+    Args:
+      args: The Namespace instance returned by argparse
+    Returns:
+      True iff the verbosity has been set to a level that includes
+          warning messages.
+    """
+    return args.verbosity in ['debug', 'info', 'default', 'warning']
+
+
 def print_info_messages(args):
     """Return whether or not info messages should be printed.
 

tools/cli/datalab.py

@@ -26,6 +26,7 @@
 import os
 import subprocess
 import traceback
+import urllib2
 
 
 _SUBCOMMANDS = {
@@ -113,6 +114,11 @@
 datalab_component = 'datalab'
 
 
+# Public file reporting all known version issues.
+version_issues_url = (
+    'https://storage.googleapis.com/cloud-datalab/version-issues.js')
+
+
 try:
     with open(os.devnull, 'w') as dn:
         subprocess.call(['gcloud', '--version'], stderr=dn, stdout=dn)
@@ -121,6 +127,31 @@
     gcloud_cmd = 'gcloud.cmd'
 
 
+def report_known_issues(sdk_version, datalab_version):
+    try:
+        version_issues_resp = urllib2.urlopen(version_issues_url)
+        version_issues = json.loads(version_issues_resp.read())
+    except urllib2.HTTPError as e:
+        print('Error downloading the version information: {}'.format(e))
+        return
+
+    sdk_issues = version_issues.get(sdk_core_component, {})
+    known_sdk_issues = sdk_issues.get(sdk_version, [])
+    if known_sdk_issues:
+        print('You are using Cloud SDK version "{}", '
+              'which has the following known issues:\n\t{}'.format(
+                  sdk_version,
+                  '\n\t'.join(known_sdk_issues)))
+    datalab_issues = version_issues.get(datalab_component, {})
+    known_datalab_issues = datalab_issues.get(datalab_version, [])
+    if known_datalab_issues:
+        print('You are using the Datalab CLI version "{}", '
+              'which has the following known issues:\n\t{}'.format(
+                  datalab_version,
+                  '\n\t'.join(known_datalab_issues)))
+    return
+
+
 def add_gcloud_verbosity_flag(args, gcloud_cmd):
     """Add the appropriate '---verbosity' flag to the given gcloud command.
 
@@ -361,6 +392,9 @@ def run():
               '\n\tCloud SDK: {}\n\tDatalab: {}'.format(
                   sdk_version, datalab_version))
 
+    if utils.print_warning_messages(args):
+        report_known_issues(sdk_version, datalab_version)
+
     gcloud_zone = ""
     if args.subcommand == 'beta':
         subcommand = _BETA_SUBCOMMANDS[args.beta_subcommand]