hermes-python 0.4.0

Python bindings for Snips Hermes Protocol

Hermes Python

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.. image:: https://travis-ci.org/snipsco/hermes-protocol.svg :target: https://travis-ci.org/snipsco/hermes-protocol

.. image:: https://badge.fury.io/py/hermes-python.svg :target: https://badge.fury.io/py/hermes-python

About

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The hermes-python library provides python bindings for the Hermes protocol that snips components use to communicate together over MQTT. hermes-python allows you to interface seamlessly with the Snips platform and kickstart development of Voice applications.

hermes-python abstracts away the connection to the MQTT bus and the parsing of incoming and outcoming messages from and to the components of the snips platform.

Requirements

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Pre-compiled wheels are available for Python 2.7+ and Python 3.5

The pre-compiled wheels supports the following platform tags :

• manylinux1_x86_64

• armv7l, armv6

• macos

If you want to install hermes-python on another platform, you have to build it from source.

Installation

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The library is packaged as a pre-compiled platform wheel, available on PyPi <https://pypi.org/project/hermes-python/>_.

It can be installed with : pip install hermes-python.

Or you can add it to your requirements.txt file.

Building from source

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If you want to use hermes-python on platforms that are not supported, you have to manually compile the wheel.

You need to have rust installed :

curl https://sh.rustup.rs -sSf

Clone, the hermes-protocol repository :

::

git clone [e-mail]:snipsco/hermes-protocol.git cd hermes-protocol

You need to compile the dynamically linked shared object library :

::

mkdir -p platforms/hermes-python/target CARGO_TARGET_DIR=platforms/hermes-python/target cargo rustc --lib --manifest-path hermes-mqtt-ffi/Cargo.toml --release -- --crate-type cdylib mv platforms/hermes-python/target/release/libhermes_mqtt_ffi.dylib platforms/hermes-python/hermes_python/dylib/

You can then build the wheel :

::

virtualenv env source env/bin/activate python setup.py bdist_wheel

The built wheels should be in platforms/hermes-python/dist

You can install those with pip : pip install platforms/hermes-python/dist/<your_wheel>.whl

Tutorial

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The lifecycle of a script using hermes-python has the following steps :

• Initiating a connection to the MQTT broker

• Registering callback functions to handle incoming intent parsed by the snips platform

• Listening to incoming intents

• Closing the connection

Let’s quickly dive into an example :

Let’s write an app for a Weather Assistant ! This code implies that you created a weather assistant using the Snips Console <https://console.snips.ai/>_, and that it has a searchWeatherForecast intent.

::

from hermes_python.hermes import Hermes

MQTT_ADDR = "localhost:1883" # Specify host and port for the MQTT broker

def subscribe_weather_forecast_callback(hermes, intent_message): # Defining callback functions to handle an intent that asks for the weather. print("Parsed intent : {}".format(intent_message.intent.intent_name))

with Hermes(MQTT_ADDR) as h: # Initialization of a connection to the MQTT broker h.subscribe_intent("searchWeatherForecast", subscribe_weather_forecast_callback) \ # Registering callback functions to handle the searchWeatherForecast intent .start() # We get out of the with block, which closes and releases the connection.

This app is a bit limited as it only prints out which intent was detected by our assistant. Let’s add more features.

Handling the IntentMessage object

In the previous example, we registered a callback that had this signature.

::

subscribe_intent_callback(hermes, intent_message)

The intent_message object contains information that was extracted from the spoken sentence.

For instance, in the previous code snippet, we extracted the name of the recognized intent with

::

intent_message.intent.intent_name

We could also retrieve the associated confidence score the NLU engine had when classifying this intent with

::

intent_message.intent.confidence_score

Extracting slots

Here are some best practices when dealing with slots. The IntentMessage object has a slots attribute.

This slots attributes is a container that is empty when the intent message doesn’t have slots :

::

assert len(intent_message.slots) == 0

This container is a dictionary where the key is the name of the slot, and the value is a list of all the slot values for this slot name.

You can access these values in two ways :

::

assert len(intent_message.slots.slot1) == 0 assert len(intent_message.slots["slot1"]) == 0

The slot values are of type NluSlot which is a deeply nested object, we offer convenience methods to rapidly access the slot_value attribute of the NluSlot.

To access the first slot_value of a slot called myslot, you can use :

::

intent_message.slots.myslot.first()

You can also access all the slot_value of a slot called myslot :

::

intent_message.slots.myslot.all()

Let’s add to our Weather assistant example.

We assume that the searchWeatherForecast has one slot called forecast_location, that indicates which location the user would like to know the weather at.

Let’s print all the forecast_location slots :

::

for slot in intent_message.slots.forecast_location: name = slot.slot_name confidence = slot.confidence_score print("For slot : {}, the confidence is : {}".format(name, confidence))

The dot notation was used, but we can also use the dictionary notation :

::

for slot in intent_message.slots.forecast_location: name = slot["slot_name"] print(name)

Some convenience methods are available to easily retrieve slot values :

Retrieving the first slot value for a given slot name

::

slot_value = intent_message.slots.forecast_location.first()

Retrieving all slot values for a given slot name

::

slot_values = intent_message.slots.forecast_location.all()

Coming back to our example, we can now have the app print the forecast_location slot value back to the user :

::

def subscribe_weather_forecast_callback(hermes, intent_message): slot_value = intent_message.slots.forecast_location.first().value print("The slot was : {}".format(slot_value)

Managing sessions

Snips platform includes support for conversations with back and forth communication between the Dialogue Manager and the client code. For a conversation, the dialogue manager creates sessions.

Starting a session

A session can be started in two manners :

• with a notification

• with an action

Ending a session

Slot Filling

Configuring MQTT options

The connection to your MQTT broker can be configured with the hermes_python.ffi.utils.MqttOptions class.

The Hermes client uses the options specified in the MqttOptions class when establishing the connection to the MQTT broker.

Here is a code example :

::

from hermes_python.hermes import Hermes from hermes_python.ffi.utils import MqttOptions

mqtt_opts = MqttOptions()

def simple_intent_callback(hermes, intent_message): print("I received an intent !")

with Hermes(mqtt_options=mqtt_opts) as h: h.subscribe_intents().loop_forever()

Here are the options you can specify in the MqttOptions class :

• broker_address: The address of the MQTT broker. It should be formatted as ip:port.

• username: Username to use on the broker. Nullable

• password: Password to use on the broker. Nullable

• tls_hostname: Hostname to use for the TLS configuration. Nullable, setting a value enables TLS

• tls_ca_file: CA files to use if TLS is enabled. Nullable

• tls_ca_path: CA path to use if TLS is enabled. Nullable

• tls_client_key: Client key to use if TLS is enabled. Nullable

• tls_client_cert: Client cert to use if TLS is enabled. Nullable

• tls_disable_root_store: Boolean indicating if the root store should be disabled if TLS is enabled.

Let’s connect to an external MQTT broker that requires a username and a password :

::

from hermes_python.hermes import Hermes from hermes_python.ffi.utils import MqttOptions

mqtt_opts = MqttOptions(username="user1", password="password", broker_address="my-mqtt-broker.com:18852")

def simple_intent_callback(hermes, intent_message): print("I received an intent !")

with Hermes(mqtt_options=mqtt_opts) as h: h.subscribe_intents().loop_forever()

Configuring Dialogue

hermes-python offers the possibility to configure different aspects of the Dialogue system.

Enabling and disabling intents on the fly

It is possible to enable and disable intents of your assistant on the fly. Once an intent is disabled, it will not be recognized by the NLU.

Note that intents in the intent filters of started or continued session will take precedence over intents that are enabled/disabled in the configuration of the Dialogue.

You can disable/enable intents with the following methods :

::

from hermes_python.ontology.dialogue.session import DialogueConfiguration

dialogue_conf = DialogueConfiguration()
.disable_intent("intent1")
.enable_intent("intent2")
.enable_intents(["intent1", "intent2"])
.disable_intents(["intent2", "intent1"])

hermes.configure_dialogue(dialogue_conf)

Release Checklist

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Everytime you need to perform a release, do the following steps : - [ ] Commit all changes to the project for said release - [ ] Write all the changes introduced in the Changelog (source/HISTORY.rst file) and commit it - [ ] Run tests - [ ] Build the documentation and commit the README.rst - [ ] Bump the version and commit it - [ ] Upload to PyPI

Build details

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Creating macOS wheels

The build script : build_scripts/build_macos_wheels.sh uses pyenv to generate hermes-python wheels for different versions of python.

To be able to run it, you need to :

• install pyenv : brew install pyenv. Then follow the additional steps detailled

• you then have to install python at different versions: pyenv install --list to list the available version to install

• Before installing and building the different python version from sources, install the required dependencies : Link here <https://github.com/pyenv/pyenv/wiki/>_

That’s it ! History

0.4.4 (2019-03-20) ^^^^^^^^^^^^^^^^^^

• Adds support to configure the Dialogue Mananger : enabling and disabling intents on the fly.
• Adds slot filling API : You can ask for a specific slot when continuing a session
• adding support for OrdinalSlot

0.3.3 (2019-03-06) ^^^^^^^^^^^^^^^^^^

• Fixes a bug with publish_start_session_notification that didn't take the text parameter into account.

0.3.2 (2019-02-25) ^^^^^^^^^^^^^^^^^^

• Fixes an important bug that gave the argument hermes the wrong type for every registered callback.
• Fixes an important bug that caused the program to crash when parsing intentMessage that had no slots.

0.3.1 (2019-02-25) ^^^^^^^^^^^^^^^^^^

• Fixes import bug with templates, the hermes_python.ffi.utils module now re-exports MqttOptions

0.3.0 (2019-02-25) ^^^^^^^^^^^^^^^^^^

• IntentClassifierResult's probability field has been renamed to confidence_score.
• Introduces support for snips-platform 1.1.0 - 0.61.1.

0.2.0 (2019-02-04) ^^^^^^^^^^^^^^^^^^

• Introduces options to connect to the MQTT broker (auth + TLS are now supported).

0.1.29 (2019-01-29) ^^^^^^^^^^^^^^^^^^^

• Fixes bug when deserializing TimeIntervalValue that used wrong encode method instead of decode.

0.1.28 (2019-01-14) ^^^^^^^^^^^^^^^^^^^

• Fixes bug when the __exit__ method was called twice on the Hermes class.
• Introduces two methods to the public api : connect and disconnect that should bring more flexibility

0.1.27 (2019-01-07) ^^^^^^^^^^^^^^^^^^^

• Fixed broken API introduced in 0.1.26 with the publish_continue_session method of the Hermes class.
• Cast any string that goes in the mqtt_server_adress parameter in the constructor of the Hermes class to be a 8-bit string.

0.1.26 (2019-01-02) ^^^^^^^^^^^^^^^^^^^^^

• LICENSING : This wheel now has the same licenses as the parent project : APACHE-MIT.
• Subscription to not recognized intent messages is added to the API. You can now write your own callbacks to handle unrecognized intents.
• Adds send_intent_not_recognized flag to continue session : indicate whether the dialogue manager should handle non recognized intents by itself or sent them as an IntentNotRecognizedMessage for the client to handle.

0.1.25 (2018-12-13) ^^^^^^^^^^^^^^^^^^^^^

• Better error handling : Errors from wrapped C library throw a LibException with detailled errors.