Update show commands to exit with code 3 upon a 404.

doc/authoring_command_modules/authoring_commands.md

@@ -99,8 +99,9 @@ with self.command_group('mymod', mymod_sdk) as g:
     # (3) Registering different types of commands
     g.command('command1', 'do_something_1')
     g.custom_command('command2', 'do_something_2')
-    g.generic_update('update', custom_function_name='my_custom_update')
-    g.generic_wait('wait')
+    g.generic_update_command('update', custom_function_name='my_custom_update')
+    g.wait_command('wait')
+    g.show_command('show')
 ```
 
 At this point, you should be able to access your command using `az [name]` and access the built-in help with `az [name] -h/--help`. Your command will automatically be 'wired up' with the global parameters.  See below for amplifying information.
@@ -141,24 +142,44 @@ The signature for `custom_command` is exactly the same as `command`. The only di
 
 See the section on "Suppporting Generic Update"
 
-***generic_wait_command***
+***wait_command***
 
 The generic wait command provides a templated solution for polling Azure resources until specific conditions are met.
 
 ```Python
-generic_wait_command(self, name, getter_name='get', getter_type=None, **kwargs)
+wait_command(self, name, getter_name='get', **kwargs)
 ```
 
 - `name`: The name of the command within the command group. Commonly called 'wait'.
 - `getter_name`: The name of the method for the object getter, relative to the path specified in `operations_tmpl`.
-- `getter_type`: A `CliCommandType` object to apply to this command (optional).
 - `kwargs`: any supported kwarg.
 
 Since most wait commands rely on a simple GET call from the SDK, most of these entries simply look like:
 ```Python
-   g.generic_wait_command('wait')
+   g.wait_command('wait')
 ```
 
+***custom_wait_command***
+
+Similar to `custom_command` and `command`, the signature for `custom_wait_command` is exactly the same as `wait_command` but uses `custom_command_type` as the fallback for missings kwargs.
+
+***show_command***
+
+The generic show command ensures a consistent behavior when encountering a missing Azure resource. 
+With little exception, all `show` commands should be registered using this method or `custom_show_command` to ensure consistency.
+
+```Python
+show_command(self, name, getter_name='get', **kwargs)
+```
+
+- `name`: The name of the command within the command group. Commonly called 'show'.
+- `getter_name`: The name of the method for the object getter, relative to the path specified in `operations_tmpl`.
+- `kwargs`: any supported kwarg.
+
+***custom_show_command***
+
+Similar to `custom_command` and `command`, the signature for `custom_show_command` is exactly the same as `show_command` but uses `custom_command_type` as the fallback for missings kwargs.
+
 **(4) Supporting --no-wait**
 
 When registering a command, the boolean `supports_no_wait` property can be used to specify that the command supports `--no-wait`.

src/azure-cli-core/azure/cli/core/commands/__init__.py

@@ -28,6 +28,7 @@
 from azure.cli.core.commands.parameters import (
     AzArgumentContext, patch_arg_make_required, patch_arg_make_optional)
 from azure.cli.core.extension import get_extension
+from azure.cli.core.util import get_command_type_kwarg, read_file_content, get_arg_list, poller_classes
 import azure.cli.core.telemetry as telemetry
 
 logger = get_logger(__name__)
@@ -60,7 +61,6 @@ def _explode_list_args(args):
 
 def _expand_file_prefixed_files(args):
     def _load_file(path):
-        from azure.cli.core.util import read_file_content
         if path == '-':
             content = sys.stdin.read()
         else:
@@ -380,7 +380,6 @@ def execute(self, args):
             is_query_active=self.data['query_active'])
 
     def _build_kwargs(self, func, ns):  # pylint: disable=no-self-use
-        from azure.cli.core.util import get_arg_list
         arg_list = get_arg_list(func)
         kwargs = {}
         if 'cmd' in arg_list:
@@ -573,7 +572,6 @@ def __call__(self, poller):
 class DeploymentOutputLongRunningOperation(LongRunningOperation):
     def __call__(self, result):
         from msrest.pipeline import ClientRawResponse
-        from azure.cli.core.util import poller_classes
 
         if isinstance(result, poller_classes()):
             # most deployment operations return a poller
@@ -677,7 +675,6 @@ def _is_paged(obj):
 def _is_poller(obj):
     # Since loading msrest is expensive, we avoid it until we have to
     if obj.__class__.__name__ in ['AzureOperationPoller', 'LROPoller']:
-        from azure.cli.core.util import poller_classes
         return isinstance(obj, poller_classes())
     return False
 
@@ -750,7 +747,7 @@ def _flatten_kwargs(self, kwargs, default_source_name):
     # pylint: disable=arguments-differ
     def command(self, name, method_name=None, **kwargs):
         """
-        Register a CLI command
+        Register a CLI command.
         :param name: Name of the command as it will be called on the command line
         :type name: str
         :param method_name: Name of the method the command maps to
@@ -762,7 +759,7 @@ def command(self, name, method_name=None, **kwargs):
             - exception_handler: Exception handler for handling non-standard exceptions (function)
             - supports_no_wait: The command supports no wait. (bool)
             - no_wait_param: [deprecated] The name of a boolean parameter that will be exposed as `--no-wait`
-              to skip long-running operation polling. (string)
+              to skip long running operation polling. (string)
             - transform: Transform function for transforming the output of the command (function)
             - table_transformer: Transform function or JMESPath query to be applied to table output to create a
                                  better output format for tables. (function or string)
@@ -771,20 +768,11 @@ def command(self, name, method_name=None, **kwargs):
             - max_api: Maximum API version required for commands within the group (string)
         :rtype: None
         """
-        self._check_stale()
-        merged_kwargs = self._flatten_kwargs(kwargs, 'command_type')
-        # don't inherit deprecation info from command group
-        merged_kwargs['deprecate_info'] = kwargs.get('deprecate_info', None)
-        operations_tmpl = merged_kwargs['operations_tmpl']
-        command_name = '{} {}'.format(self.group_name, name) if self.group_name else name
-        operation = operations_tmpl.format(method_name) if operations_tmpl else None
-        self.command_loader._cli_command(command_name, operation, **merged_kwargs)  # pylint: disable=protected-access
-
-        return command_name
+        return self._command(name, method_name=method_name, **kwargs)
 
-    def custom_command(self, name, method_name, **kwargs):
+    def custom_command(self, name, method_name=None, **kwargs):
         """
-        Register a custom CLI command.
+        Register a CLI command.
         :param name: Name of the command as it will be called on the command line
         :type name: str
         :param method_name: Name of the method the command maps to
@@ -805,8 +793,11 @@ def custom_command(self, name, method_name, **kwargs):
             - max_api: Maximum API version required for commands within the group (string)
         :rtype: None
         """
+        return self._command(name, method_name=method_name, custom_command=True, **kwargs)
+
+    def _command(self, name, method_name, custom_command=False, **kwargs):
         self._check_stale()
-        merged_kwargs = self._flatten_kwargs(kwargs, 'custom_command_type')
+        merged_kwargs = self._flatten_kwargs(kwargs, get_command_type_kwarg(custom_command))
         # don't inherit deprecation info from command group
         merged_kwargs['deprecate_info'] = kwargs.get('deprecate_info', None)
 
@@ -819,12 +810,8 @@ def custom_command(self, name, method_name, **kwargs):
         return command_name
 
     # pylint: disable=no-self-use
-    def _resolve_operation(self, kwargs, name, command_type=None, source_kwarg='command_type'):
-
-        allowed_source_kwargs = ['command_type', 'custom_command_type']
-        if source_kwarg not in allowed_source_kwargs:
-            raise ValueError("command authoring error: 'source_kwarg' value '{}'. Allowed values: {}".format(
-                source_kwarg, ' '.join(allowed_source_kwargs)))
+    def _resolve_operation(self, kwargs, name, command_type=None, custom_command=False):
+        source_kwarg = get_command_type_kwarg(custom_command)
 
         operations_tmpl = None
         if command_type:
@@ -860,7 +847,7 @@ def generic_update_command(self, name,
         getter_op = self._resolve_operation(merged_kwargs, getter_name, getter_type)
         setter_op = self._resolve_operation(merged_kwargs, setter_name, setter_type)
         custom_func_op = self._resolve_operation(merged_kwargs, custom_func_name, custom_func_type,
-                                                 source_kwarg='custom_command_type') if custom_func_name else None
+                                                 custom_command=True) if custom_func_name else None
         _cli_generic_update_command(
             self.command_loader,
             '{} {}'.format(self.group_name, name),
@@ -873,31 +860,43 @@ def generic_update_command(self, name,
             child_arg_name=child_arg_name,
             **merged_kwargs)
 
+    def wait_command(self, name, getter_name='get', **kwargs):
+        self._wait_command(name, getter_name=getter_name, custom_command=False, **kwargs)
+
+    def custom_wait_command(self, name, getter_name='get', **kwargs):
+        self._wait_command(name, getter_name=getter_name, custom_command=True, **kwargs)
+
     def generic_wait_command(self, name, getter_name='get', getter_type=None, **kwargs):
-        from azure.cli.core.commands.arm import _cli_generic_wait_command
+        self._wait_command(name, getter_name=getter_name, getter_type=getter_type, **kwargs)
+
+    def _wait_command(self, name, getter_name='get', getter_type=None, custom_command=False, **kwargs):
+        from azure.cli.core.commands.arm import _cli_wait_command
         self._check_stale()
         merged_kwargs = _merge_kwargs(kwargs, self.group_kwargs, CLI_COMMAND_KWARGS)
         # don't inherit deprecation info from command group
         merged_kwargs['deprecate_info'] = kwargs.get('deprecate_info', None)
 
         if getter_type:
             merged_kwargs = _merge_kwargs(getter_type.settings, merged_kwargs, CLI_COMMAND_KWARGS)
-        getter_op = self._resolve_operation(merged_kwargs, getter_name, getter_type)
-        _cli_generic_wait_command(
-            self.command_loader,
-            '{} {}'.format(self.group_name, name),
-            getter_op=getter_op,
-            **merged_kwargs)
+        getter_op = self._resolve_operation(merged_kwargs, getter_name, getter_type, custom_command=custom_command)
+        _cli_wait_command(self.command_loader, '{} {}'.format(self.group_name, name), getter_op=getter_op,
+                          custom_command=custom_command, **merged_kwargs)
 
-    def generic_show_command(self, name, getter_name='get', getter_type=None, **kwargs):
-        from azure.cli.core.commands.arm import _cli_generic_show_command
+    def show_command(self, name, getter_name='get', **kwargs):
+        self._show_command(name, getter_name=getter_name, custom_command=False, **kwargs)
+
+    def custom_show_command(self, name, getter_name='get', **kwargs):
+        self._show_command(name, getter_name=getter_name, custom_command=True, **kwargs)
+
+    def _show_command(self, name, getter_name='get', getter_type=None, custom_command=False, **kwargs):
+        from azure.cli.core.commands.arm import _cli_show_command
         self._check_stale()
         merged_kwargs = _merge_kwargs(kwargs, self.group_kwargs, CLI_COMMAND_KWARGS)
+        # don't inherit deprecation info from command group
+        merged_kwargs['deprecate_info'] = kwargs.get('deprecate_info', None)
+
         if getter_type:
             merged_kwargs = _merge_kwargs(getter_type.settings, merged_kwargs, CLI_COMMAND_KWARGS)
-        getter_op = self._resolve_operation(merged_kwargs, getter_name, getter_type)
-        _cli_generic_show_command(
-            self.command_loader,
-            '{} {}'.format(self.group_name, name),
-            getter_op=getter_op,
-            **merged_kwargs)
+        getter_op = self._resolve_operation(merged_kwargs, getter_name, getter_type, custom_command=custom_command)
+        _cli_show_command(self.command_loader, '{} {}'.format(self.group_name, name), getter_op=getter_op,
+                          custom_command=custom_command, **merged_kwargs)