the regex used to validate an event hub namespace name seems to be incorrect

[Chris-Marcantonio]

Describe the bug

The documentation available, as well as context hints in the Azure portal indicate that an event hub namespace name can be between 6 and 50 characters long. For example, see:

https://learn.microsoft.com/en-us/azure/templates/microsoft.eventhub/namespaces?pivots=deployment-language-bicep#microsofteventhubnamespaces

And when entering a name in the Azure portal, there is a tip that says "The value must be between 6 and 50 characters long" in red.

However, if you look at the regex in the link above, it is shown as:

^[a-zA-Z][a-zA-Z0-9-]{6,50}[a-zA-Z0-9]$

Which I believe is wrong. And this doesn't appear to be just a documentation bug...when I run an az cli command against something, I get an error that shows the same regex, and that my name does not match it, despite it being 7 characters long:

InvalidArgumentValue: -n: Invalid format: 'dev-lab' does not fully match regular expression pattern '^[a-zA-Z][a-zA-Z0-9-]{6,50}[a-zA-Z0-9]$'

I'm pretty sure that {6,50} in the middle should in fact be {4,48} in order to properly match a name that is between 6 and 50 characters long. For example, it fails to properly validate a name length of 6 or 7 characters, but passes for something 8 characters:

PS /> if ("foobar" -match "^[a-zA-Z][a-zA-Z0-9-]{6,50}[a-zA-Z0-9]$") { Write-Host "yep" }
PS /> if ("foobar1" -match "^[a-zA-Z][a-zA-Z0-9-]{6,50}[a-zA-Z0-9]$") { Write-Host "yep" }
PS /> if ("foobar12" -match "^[a-zA-Z][a-zA-Z0-9-]{6,50}[a-zA-Z0-9]$") { Write-Host "yep" }
yep
PS />

And there is a similar failure for lengths that are tested against what should be a length limit of 50:

PS /> $foo = "abcdefghijklmnopqrstuvwxyzXxXx01234567890123456789xx"
PS /> $foo.length
52
PS /> if ($foo -match "^[a-zA-Z][a-zA-Z0-9-]{6,50}[a-zA-Z0-9]$") { Write-Host "yep" }
yep
PS />

If I adjust that regex to:

^[a-zA-Z][a-zA-Z0-9-]{4,48}[a-zA-Z0-9]$

then things work as expected:

PS /> if ("fooba" -match "^[a-zA-Z][a-zA-Z0-9-]{4,48}[a-zA-Z0-9]$") { Write-Host "yep" }
PS /> if ("foobar" -match "^[a-zA-Z][a-zA-Z0-9-]{4,48}[a-zA-Z0-9]$") { Write-Host "yep" }
yep
PS />
PS /> $foo = "abcdefghijklmnopqrstuvwxyzXxXx01234567890123456789"
PS /> $foo.length
50
PS /> if ($foo -match "^[a-zA-Z][a-zA-Z0-9-]{4,48}[a-zA-Z0-9]$") { Write-Host "yep" }
yep
PS />
PS /> $foo = "abcdefghijklmnopqrstuvwxyzXxXx01234567890123456789x"
PS /> $foo.length
51
PS /> if ($foo -match "^[a-zA-Z][a-zA-Z0-9-]{4,48}[a-zA-Z0-9]$") { Write-Host "yep" }
PS />

Related command

az eventhubs namespace show

Errors

InvalidArgumentValue: -n: Invalid format: 'dev-lab' does not fully match regular expression pattern '^[a-zA-Z][a-zA-Z0-9-]{6,50}[a-zA-Z0-9]$'

Issue script & Debug output

PS /> az eventhubs namespace show --ids REDACTED --debug
cli.knack.cli: Command arguments: ['eventhubs', 'namespace', 'show', '--ids', 'REDACTED', '--debug']
cli.knack.cli: init debug log:
Enable color in terminal.
cli.knack.cli: Event: Cli.PreExecute []
cli.knack.cli: Event: CommandParser.OnGlobalArgumentsCreate [<function CLILogging.on_global_arguments at 0x100a031a0>, <function OutputProducer.on_global_arguments at 0x100d42480>, <function CLIQuery.on_global_arguments at 0x100d7bc40>]
cli.knack.cli: Event: CommandInvoker.OnPreCommandTableCreate []
cli.azure.cli.core: Modules found from index for 'eventhubs': ['azure.cli.command_modules.eventhubs']
cli.azure.cli.core: Loading command modules:
cli.azure.cli.core: Name Load Time Groups Commands
cli.azure.cli.core: eventhubs 0.135 17 34
cli.azure.cli.core: Total (1) 0.135 17 34
cli.azure.cli.core: These extensions are not installed and will be skipped: ['azext_ai_examples', 'azext_next']
cli.azure.cli.core: Loading extensions:
cli.azure.cli.core: Name Load Time Groups Commands Directory
cli.azure.cli.core: Total (0) 0.000 0 0
cli.azure.cli.core: Loaded 17 groups, 34 commands.
cli.azure.cli.core: Found a match in the command table.
cli.azure.cli.core: Raw command : eventhubs namespace show
cli.azure.cli.core: Command table: eventhubs namespace show
cli.knack.cli: Event: CommandInvoker.OnPreCommandTableTruncate [<function AzCliLogging.init_command_file_logging at 0x1021f2200>]
cli.azure.cli.core.azlogging: metadata file logging enabled - writing logs to 'REDACTED'.
az_command_data_logger: command args: eventhubs namespace show --ids {} --debug
cli.knack.cli: Event: CommandInvoker.OnPreArgumentLoad [<function register_global_subscription_argument..add_subscription_parameter at 0x102227920>]
cli.knack.cli: Event: CommandInvoker.OnPostArgumentLoad []
cli.knack.cli: Event: CommandInvoker.OnPostCommandTableCreate [<function register_ids_argument..add_ids_arguments at 0x102285c60>, <function register_cache_arguments..add_cache_arguments at 0x102285da0>, <function register_upcoming_breaking_change_info..update_breaking_change_info at 0x102285e40>]
cli.knack.cli: Event: CommandInvoker.OnCommandTableLoaded []
cli.knack.cli: Event: CommandInvoker.OnPreParseArgs []
cli.knack.cli: Event: CommandInvoker.OnPostParseArgs [<function OutputProducer.handle_output_argument at 0x100d42520>, <function CLIQuery.handle_query_parameter at 0x100d7bce0>, <function register_ids_argument..parse_ids_arguments at 0x102285d00>]
cli.azure.cli.core.azclierror: Traceback (most recent call last):
File "/opt/homebrew/Cellar/azure-cli/2.70.0/libexec/lib/python3.12/site-packages/azure/cli/core/aaz/_command_ctx.py", line 53, in format_args
self.args._schema._fmt(ctx=self, value=self.args)
File "/opt/homebrew/Cellar/azure-cli/2.70.0/libexec/lib/python3.12/site-packages/azure/cli/core/aaz/_arg_fmt.py", line 402, in call
raise err from err
File "/opt/homebrew/Cellar/azure-cli/2.70.0/libexec/lib/python3.12/site-packages/azure/cli/core/aaz/_arg_fmt.py", line 399, in call
value[field_name] = field_schema._fmt(ctx, value[field_name])
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/Cellar/azure-cli/2.70.0/libexec/lib/python3.12/site-packages/azure/cli/core/aaz/_arg_fmt.py", line 56, in call
raise AAZInvalidArgValueError(
azure.cli.core.aaz.exceptions.AAZInvalidArgValueError: InvalidArgumentValue: -n: Invalid format: 'dev-lab' does not fully match regular expression pattern '^[a-zA-Z][a-zA-Z0-9-]{6,50}[a-zA-Z0-9]$'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/opt/homebrew/Cellar/azure-cli/2.70.0/libexec/lib/python3.12/site-packages/knack/cli.py", line 233, in invoke
cmd_result = self.invocation.execute(args)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/Cellar/azure-cli/2.70.0/libexec/lib/python3.12/site-packages/azure/cli/core/commands/init.py", line 666, in execute
raise ex
File "/opt/homebrew/Cellar/azure-cli/2.70.0/libexec/lib/python3.12/site-packages/azure/cli/core/commands/init.py", line 734, in _run_jobs_serially
results.append(self._run_job(expanded_arg, cmd_copy))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/Cellar/azure-cli/2.70.0/libexec/lib/python3.12/site-packages/azure/cli/core/commands/init.py", line 703, in _run_job
result = cmd_copy(params)
^^^^^^^^^^^^^^^^
File "/opt/homebrew/Cellar/azure-cli/2.70.0/libexec/lib/python3.12/site-packages/azure/cli/core/aaz/_command.py", line 155, in call
return self._handler(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/Cellar/azure-cli/2.70.0/libexec/lib/python3.12/site-packages/azure/cli/command_modules/eventhubs/aaz/latest/eventhubs/namespace/_show.py", line 32, in _handler
super()._handler(command_args)
File "/opt/homebrew/Cellar/azure-cli/2.70.0/libexec/lib/python3.12/site-packages/azure/cli/core/aaz/_command.py", line 165, in _handler
self.ctx.format_args()
File "/opt/homebrew/Cellar/azure-cli/2.70.0/libexec/lib/python3.12/site-packages/azure/cli/core/aaz/_command_ctx.py", line 55, in format_args
raise InvalidArgumentValueError(str(err))
azure.cli.core.azclierror.InvalidArgumentValueError: InvalidArgumentValue: -n: Invalid format: 'dev-lab' does not fully match regular expression pattern '^[a-zA-Z][a-zA-Z0-9-]{6,50}[a-zA-Z0-9]$'

cli.azure.cli.core.azclierror: InvalidArgumentValue: -n: Invalid format: 'dev-lab' does not fully match regular expression pattern '^[a-zA-Z][a-zA-Z0-9-]{6,50}[a-zA-Z0-9]$'
az_command_data_logger: InvalidArgumentValue: -n: Invalid format: 'dev-lab' does not fully match regular expression pattern '^[a-zA-Z][a-zA-Z0-9-]{6,50}[a-zA-Z0-9]$'
cli.knack.cli: Event: Cli.PostExecute [<function AzCliLogging.deinit_cmd_metadata_logging at 0x1021f2480>]
az_command_data_logger: exit code: 1
cli.main: Command ran in 0.371 seconds (init: 0.163, invoke: 0.207)
telemetry.main: Begin splitting cli events and extra events, total events: 1
telemetry.client: Accumulated 0 events. Flush the clients.
telemetry.main: Finish splitting cli events and extra events, cli events: 1
telemetry.save: Save telemetry record of length 4064 in cache file under /Users/REDACTED/.azure/telemetry/20250321152414410
telemetry.main: Begin creating telemetry upload process.
telemetry.process: Creating upload process: "/opt/homebrew/Cellar/azure-cli/2.70.0/libexec/bin/python /opt/homebrew/Cellar/azure-cli/2.70.0/libexec/lib/python3.12/site-packages/azure/cli/telemetry/init.py /Users/REDACTED/.azure /Users/REDACTED/.azure/telemetry/20250321152414410"
telemetry.process: Return from creating process 42974
telemetry.main: Finish creating telemetry upload process.
PS />

Expected behavior

The name used is valid, so it should not fail validation to that regex.

Environment Summary

azure-cli: stable 2.70.0

Additional context

No response

[yonzhan]

Thank you for opening this issue, we will look into it.

[microsoft-github-policy-service]

Thanks for the feedback! We are routing this to the appropriate team for follow-up. cc @Saglodha.