phantom-dev 0.5.0

Utilities to simplify Phantom app development

phantom-dev

Utilities for simplifying the development of Phantom apps

Author

David Finn: [e-mail]

Requirements

• Splunk>Phantom
• Python 3.6 or higher

Installation

pip install phantom-dev

Description

phantom-dev is a command-line utility for creating, building, and deploying Phantom apps.

App packages are built from project directories containing a YAML metadata file and a connector implemented in Python. Any other files in the project directory will be packaged and included with the app.

App Metadata

The metadata.yaml file in the project directory will be used to generate the app JSON expected by the Phantom platform. Minor alterations to the JSON structure have been made to assist with readability and maintainability; related keys have been grouped under a common prefix key (e.g. JSON project-* keys are defined under the project object in the YAML) and lists of uniquely-identifiable objects have been converted to objects (e.g. JSON actions is now a mapping of action names to action data, rather than a list of action objects with unique and potentially conflicting names).

For information on the generated app metadata, see the official Phantom documentation.

Connector Implementation

The phantom_dev.action_handler module greatly simplifies the implementation of a phantom.base_connector.BaseConnector subclass, which is the basis for Phantom app development.

Action handler methods defined using the phantom_dev.action_handler.ActionHandler decorator will be used to dynamically infer action metadata unless overridden in the metadata file. Action names, parameter names, and parameter types can all be inferred from the implementation assuming parameters are type-annotated in the code.

The phantom_dev.action_handler module will be automatically embedded in the dependencies directory when the app is built, allowing the developer to make full use of the module without being concerned with managing it as a dependency.

Edge cases and use of more specialised BaseConnector methods should be dealt with as normal, in accordance with the official Phantom documentation.

Quickstart

Running phantom-dev create will prompt the user for the set of details required to define a Phantom app.

$ phantom-dev create "My Special App"
Product Vendor: Special Vendor
Product Name: Special Product
Description: My special little app
Publisher: David Finn
License: Special license

A new project directory will be created and populated with a metadata.yaml and a connector.py. The metadata YAML will contain the details provided by the user, and the connector module will define an example connector implementation. The metadata will also be populated with action information required by the example connector implementation.

Extending the App

The following defines the implementation of a new action called "echo message":

from phantom_dev.action_handler import ActionHandler, smart_connector
...
@smart_connector
class Connector:
	...
	@ActionHandler
	def echo_message(self, message: str):
		"""
		Echo a message

		:param message: The message to be echoed
		"""
		yield {'response': message}
	...

	@echo_message.summary
	def summarise_echo(self, results):
		result, = results
		return {'response': result['response']}
...

If possible, the action description will be inferred from the method docstring- in this case, "Echo a message". Similarly, parameter descriptions will also be inferred if specified in the docstring with appropriate docstring syntax (currently, Sphinx syntax is confirmed to work). In this case, the description for the paramter message will be "The message to be echoed".

The action summary data for the echo message action is created by decorating the summary method with @echo_message.summary. Action summary methods take the action results as an iterable, and create the appropriate summary data.

Thanks to smart_connector, all methods of the BaseConnector class are available for use in the action handler logic implementation.

Although the app will successfully install and run given the above metadata, it's still missing output fields and contains information. Unless specfied in metadata.yaml, phantom-dev (and therefore Phantom) has no way of knowing that the output data should contain a response field with a data_type of string. If we want to add contains information, such as setting a contains value of ['text'] for the message and response, we also need to specify these somewhere.

These can be specified as normal using metadata.yaml, but this can also be done directly using approrpate ActionHandler methods:

from phantom_dev.action_handler import ActionHandler, contains, smart_connector
...

@contains('text')
class Text(str):
	"""A string-based type which contains `['text']`"""

...

@smart_connector
class Connector:
	...
	@ActionHandler.data_contains({'response': Text})
	def echo_message(self, message: Text):
		"""
		Echo a message

		:param message: The message to be echoed
		"""
		yield {'response': message}

	@echo_message.summary_contains({'response': Text})
	def summarise_echo(self, results):
		result, = results
		return {'response': result['response']}
	...
...

Several things are happening here. First, a new type called Text inherits from str and is decorated with the @contains decorator, mapping it to a contains value of ['text']. This type is used instead of str to annotate the message parameter of the action, which allows phantom-dev to infer both the data_type and the contains value for the parameter.

Next, the data_contains decorator is being used to decorate the action method, and a mapping of 'response' to Text is being specified as the argument. This allows phantom-dev to infer that each data result has a field named 'response', and that its data_type and contains information should be inferred from the Text type the same way it was for the message parameter.

Finally, the same thing is being done with the echo_message.summary_contains decorator (used instead of summary), though in this case it's the action summary fields rather than the results data fields that are being described.

Use of these decorators is preferred to metadata.yaml specification, as they keep metadata definitions colocated with the data they describe. They also encourage code reuse though the use of common contains-mapped type definitions, shareable between both parameters and output fields.

Dependencies

Any package specified in requirements.txt in the app project directory will be automatically downloaded and packaged with the app. requirements.txt should be a normal pip requirements file.

For example, if the app requires the roboversion package, a requirements.txt could be created with the following content:

roboversion>=2

When the app is built, the roboversion wheel will be automatically downloaded and included in the package wheels directory, and the autogenerated app JSON will specify its location for Phantom installation.

Deploying the App

Once the app is ready to install, assuming a Phantom server location of phantom.example.com:

$ phantom-dev push my_special_app/ [e-mail]

Note: The Phantom server must be a known host; SSH to it first to confirm credentials and connectivity.

The user will be prompted for the SSH password. Once supplied, the app will be automatically packaged, sent to the Phantom server, and installed.

The SSH password can also be provided as part of the command:

$ phantom-dev push my_special_app/ root:[e-mail]

If certificate authentication is used, an empty password can be also be specified:

$ phantom-dev push my_special_app/ root:@phantom.example.com

Other commands

For information on the other phantom-dev subcommands including package and deploy, run:

$ phantom-dev --help
$ phantom-dev <subcommand> --help

Details

In the above example, use of the ActionHandler (orActionHandler.data_contains) decorator wraps the decorated echo_message method in the logic required for error handling and results reporting. The param dictionary is automatically unpacked as keyword arguments to handler method, allowing for quick and explicit argument validation and intuitive access to action parameters. param contains the parameters described in the app JSON.

Handler methods such as echo_message are expected to return iterables of results data. The items from this iterable are added as data objects to the ActionResult. Implementing handler methods as generators is highly convenient, as this allows custom logic to be run any time before or after data is yielded, but methods can also be implemented as normal functions that return iterable objects.

The HandlerMixin superclass provided by smart_connector automatically delegates incoming actions to the correct method based on the action identifier.

smart_connector also wraps the functionality of a the main_connector decorator. main_connector simply calls the class's main method if the class is defined in the __main__ module, reproducing the testing functionality provided by autogenerated app wizard code.

Signaling Failure

Failure is signaled through raising exceptions. If the handler executes without raising an exception, the action is treated as a success.

To implement an echo fail action that does the same thing as echo message, but always fails after producing results:

...
@contains('text')
class Text(str):
	"""A string-based type which contains `['text']`"""

...

@smart_connector
class Connector:
	...
	@ActionHandler.data_contains({'response': Text})
	def echo_message(self, message: Text):
		"""
		Echo a message

		:param message: The message to be echoed
		"""
		yield {'response': message}

	@echo_message.summary_contains({'response': Text})
	def summarise_echo(self, results):
		result, = results
		return {'response': result['response']}
	...

	@ActionHandler.data_contains({'response': Text})
	def echo_fail(self, **param):
		"""
		Echo the message as normal, then fail
		"""
		# Demonstration of re-packing param; this will be the same as the
		# original param dictionary, which we can then unpack for the call
		# to echo_message.
		# Unfortunately, this will require manual specification of more
		# parameter metadata.
		yield from self.echo_message(**param)
		raise RuntimeError('Failed on purpose')

	# The same summary method can be decorated multiple times for different
	# handlers to duplicate functionality
	@echo_fail.summary_contains({'response': Text})
	@echo_message.summary_contains({'response': Text})
	def summarise_echo(self, results):
		result, = results
		return {'response': result['response']}

In the example, parameter packing with **param was used instead of describing and annotating the paramters for echo fail. This is possible but not recommended, because now the user must manually specify more parameter information in metadata.yaml:

...
actions:
	...
	echo_fail:
		parameters:
			message:
				data_type: string
				description: The message to be echoed
				required: true
				contains:
					- text
	...
...

Actions with no results

test connectivity is an example of an action which produces no results. The handler method needs only to return an empty iterable, which is easily accomplished by returning an empty collection rather than implementing a generator:

...
@contains('text')
class Text(str):
	"""A string-based type which contains `['text']`"""

...

@smart_connector
class Connector:
	...
	@ActionHandler.data_contains({'response': Text})
	def echo_message(self, message: Text):
		"""
		Echo a message

		:param message: The message to be echoed
		"""
		yield {'response': message}

	@echo_message.summary_contains({'response': Text})
	def summarise_echo(self, results):
		result, = results
		return {'response': result['response']}
	...

	@ActionHandler.data_contains({'response': Text})
	def echo_fail(self, **param):
		"""
		Echo the message as normal, then fail
		"""
		# Demonstration of re-packing param; this will be the same as the
		# original param dictionary, which we can then unpack for the call
		# to echo_message.
		# Unfortunately, this will require manual specification of more
		# parameter metadata.
		yield from self.echo_message(**param)
		raise RuntimeError('Failed on purpose')

	# The same summary method can be decorated multiple times for different
	# handlers to duplicate functionality
	@echo_fail.summary_contains({'response': Text})
	@echo_message.summary_contains({'response': Text})
	def summarise_echo(self, results):
		result, = results
		return {'response': result['response']}

	@ActionHandler
	def test_connectivity(self):
		"""
		Check `echo message` and `echo fail`
		"""
		# The test connectivity action is a special case that does not
		# receive a param dictionary at all, so there are no arguments to
		# unpack
		test_value = 'SOME TEST MESSAGE'
		results = []
		try:
			for result in self.echo_fail(test_value):
				results.append(result)
		except RuntimeError:
			pass
		else:
			raise RuntimeError('echo fail failed to fail')

		message, = results
		if message != test_value:
			raise ValueError('echo fail failed to echo')

		return []

It would also be possible to achieve this with a return statement before a yield statement in a generator, or by failing before any results are yielded.

Action Context

The hidden phantom action context parameter can be accessed as the context member of the connector object during action execution. This data contains entries for artifact_id, guid, and parent_action_run; see 'Understanding Datapaths' in the offical phantom documentation for details.

Logging

The logger member of the connector object is a standard Python logging.Logger object that can be used in the normal way.

All log messages of ERROR and above will be logged to /var/log/spawn.log. If the system is configured for DEBUG logging, all messages of DEBUG and above will also be logged. Additionally, all log messages of level INFO and above will be reported using BaseConnector.save_progress regardless of Phantom debug configuration.

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