Dogshell.dog service_check, monitor includes null values

[ronindesign]

dog script's service_check, monitor options are not required, but are still sent (as null) when not provided. Assuming this is the behavior for all script commands.

Reproduce:

$ dog service_check check check_pg host0 0
ERROR: "message" parameter should be a string

The actual payload / body sent to server includes nulled options, when not specified.

{"status": 0, "tags": null, "timestamp": null, "host_name": "host0", "message": null, "check": "check_pg"}

Relates:
https://github.com/DataDog/datadogpy/blob/master/datadog/dogshell/service_check.py#L32
https://github.com/DataDog/datadogpy/blob/master/datadog/api/service_checks.py#L39
https://github.com/DataDog/datadogpy/blob/master/datadog/api/api_client.py#L112
https://github.com/DataDog/datadogpy/blob/master/datadog/api/api_client.py#L127

This could be fixed locally in datadog.dogshell.service_checkto not submitNoneoptions; or this could be fixed indatadog.api.service_checksordatadog.api.api_client`.

The first would have the most localized effect / least possibility for wider side effects to other tests, but if there are no cases for submitting null values to the DataDog API, then I would definitely recommend mitigating this directly in datadog.api.api_client.

[timvisher]

The commits that fixed this introduced a python error:

root@tvisher1:~# dog service_check check check_filebeat "$(hostname)" 2
Traceback (most recent call last):
  File "/usr/local/bin/dog", line 11, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.4/dist-packages/datadog/dogshell/__init__.py", line 69, in main
    args.func(args)
  File "/usr/local/lib/python3.4/dist-packages/datadog/dogshell/service_check.py", line 34, in _check
    timestamp=args.timestamp, message=args.message, tags=args.tags)
  File "/usr/local/lib/python3.4/dist-packages/datadog/api/service_checks.py", line 37, in check
    for param, value in params.items():
RuntimeError: dictionary changed size during iteration
r

I applied the following patch and it worked well.

--- /usr/local/lib/python3.4/dist-packages/datadog/api/service_checks.orig.py   2017-11-10 11:00:23.925812101 -0500
+++ /usr/local/lib/python3.4/dist-packages/datadog/api/service_checks.py        2017-11-10 11:00:43.198480330 -0500
@@ -35,9 +35,7 @@

         # Validate checks, include only non-null values
         for param, value in params.items():
-            if value is None:
-                del params[param]
-            elif param == 'status' and params[param] not in CheckStatus.ALL:
+            if param == 'status' and params[param] not in CheckStatus.ALL:
                 raise ApiError('Invalid status, expected one of: %s'
                                % ', '.join(str(v) for v in CheckStatus.ALL))

I'll try to submit a PR.