Unable to create role assignment via az rest: ValueError: not enough values to unpack (expected 2, got 1)

Describe the bug

When trying to create a role assignment as shown here, I cannot seem to bypass the traceback error detailed below. However, this DOES work when executed via cURL.

Command Name az rest

Errors:

The command failed with an unexpected error. Here is the traceback:
not enough values to unpack (expected 2, got 1)
Traceback (most recent call last):
  File "/opt/az/lib/python3.8/site-packages/azure/cli/core/util.py", line 538, in shell_safe_json_parse
    return json.loads(json_or_dict_string, strict=strict)
  File "/opt/az/lib/python3.8/json/__init__.py", line 370, in loads
    return cls(**kw).decode(s)
  File "/opt/az/lib/python3.8/json/decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/opt/az/lib/python3.8/json/decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/opt/az/lib/python3.8/site-packages/azure/cli/core/util.py", line 844, in send_raw_request
    temp = shell_safe_json_parse(s)
  File "/opt/az/lib/python3.8/site-packages/azure/cli/core/util.py", line 563, in shell_safe_json_parse
    raise InvalidArgumentValueError(msg, recommendation=recommendation) from json_ex
azure.cli.core.azclierror.InvalidArgumentValueError: Failed to parse JSON: Content-Type: application/json
Error detail: Expecting value: line 1 column 1 (char 0)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/az/lib/python3.8/site-packages/knack/cli.py", line 231, in invoke
    cmd_result = self.invocation.execute(args)
  File "/opt/az/lib/python3.8/site-packages/azure/cli/core/commands/__init__.py", line 658, in execute
    raise ex
  File "/opt/az/lib/python3.8/site-packages/azure/cli/core/commands/__init__.py", line 721, in _run_jobs_serially
    results.append(self._run_job(expanded_arg, cmd_copy))
  File "/opt/az/lib/python3.8/site-packages/azure/cli/core/commands/__init__.py", line 692, in _run_job
    result = cmd_copy(params)
  File "/opt/az/lib/python3.8/site-packages/azure/cli/core/commands/__init__.py", line 328, in __call__
    return self.handler(*args, **kwargs)
  File "/opt/az/lib/python3.8/site-packages/azure/cli/core/commands/command_operation.py", line 121, in handler
    return op(**command_args)
  File "/opt/az/lib/python3.8/site-packages/azure/cli/command_modules/util/custom.py", line 23, in rest_call
    r = send_raw_request(cmd.cli_ctx, method, url, headers, uri_parameters, body,
  File "/opt/az/lib/python3.8/site-packages/azure/cli/core/util.py", line 847, in send_raw_request
    key, value = s.split('=', 1)
ValueError: not enough values to unpack (expected 2, got 1)

To Reproduce:

Steps to reproduce the behavior. Note that argument values have been redacted, as they may contain sensitive information.

• The az rest commands have been ran on both WSL Ubuntu and native PowerShell.
• Doesn’t work:
  • az rest --method post --header "Content-Type: application/json" --url "https://graph.microsoft.com/v1.0/roleManagement/directory/roleAssignments" --body '{"@odata.type": "#microsoft.graph.unifiedRoleAssignment", "roleDefinitionId": "<redacted>", "principalId": "<redacted>", "directoryScopeId": "/"}'
• Works
  • curl -sL -H "Authorization: bearer $(az account get-access-token --scope https://graph.microsoft.com/.default --query accessToken -o tsv)" -H "Content-Type: application/json" "https://graph.microsoft.com/v1.0/roleManagement/directory/roleAssignments" -X POST --data '{"@odata.type": "#microsoft.graph.unifiedRoleAssignment", "roleDefinitionId": "<redacted>", "principalId": "<redacted>", "directoryScopeId": "/"}'

Expected Behavior

{
  "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#roleManagement/directory/roleAssignments/$entity",
  "id": "<redacted>",
  "principalId": "<redacted>",
  "directoryScopeId": "/",
  "roleDefinitionId": "<redacted>"
}

Environment Summary

Linux-4.4.0-19041-Microsoft-x86_64-with-glibc2.29, Ubuntu 20.04.4 LTS
Python 3.8.12
Installer: DEB

azure-cli 2.34.1

Extensions:
account 0.2.2
azure-devops 0.22.0
support 1.0.3

Dependencies:
msal 1.16.0
azure-mgmt-resource 20.0.0

Additional Context

[jiasli]

it complained about not having one, but as you pointed out it did work just now.

This is usually because the body is not a valid JSON, sometimes parsed by the shell, like double quotes ".

You are welcome. If you see any problem with az rest, please don’t hesitate to let us know. 😊

[jaredbrogan]

@jaredbrogan, the failed line is:

https://github.com/Azure/azure-cli/blob/07819726e13d72587eb82b65c92ecba3bb009f32/src/azure-cli-core/azure/cli/core/util.py#L847

It fails because the header format is incorrect. Actually, you don’t need to specify header Content-Type at all:

> az rest -h

...
        If Content-Type header is not set and --body is a valid JSON string, Content-Type header
        will default to application/json.

Arguments
...
    --headers                         : Space-separated headers in KEY=VALUE format or JSON string.
                                        Use @{file} to load from a file.

Also, if you run the command in native PowerShell, pay attention to quoting issues: https://github.com/Azure/azure-cli/blob/dev/doc/quoting-issues-with-powershell.md

🤦‍♂️ Ugh… Thanks for pointing that out. I swear I tried it several times with and without the header. At one point without providing the header outright, it complained about not having one, but as you pointed out it did work just now.

Appreciate the sanity check on this one! 🙂