Writing interactive bots
This guide is about writing and testing interactive bots. We assume
familiarity with our guide for running bots.
On this page you'll find:
- A step-by-step
guide
on how to set up a development environment for writing bots with all
of our nice tooling to make it easy to write and test your work.
- A guide on writing a bot.
- A guide on adding a bot to Zulip.
- A guide on testing a bot's output.
- Documentation of the bot API.
- Common problems when developing/running bots and their solutions.
Installing a development version of the Zulip bots package
-
git clone https://github.com/zulip/python-zulip-api.git
- clone the python-zulip-api repository.
-
cd python-zulip-api
- navigate into your cloned repository.
-
python3 ./tools/provision
- install all requirements in a Python virtualenv.
-
The output of provision
will end with a command of the form source .../activate
;
run that command to enter the new virtualenv.
-
Finished. You should now see the name of your venv preceding your prompt,
e.g. (zulip-api-py3-venv)
.
Hint: provision
installs the zulip
, zulip_bots
, and
zulip_botserver
packages in developer mode. This enables you to
modify these packages and then run your modified code without
having to first re-install the packages or re-provision.
Writing a bot
The tutorial below explains the structure of a bot <my-bot>.py
,
which is the only file you need to create for a new bot. You
can use this as boilerplate code for developing your own bot.
Every bot is built upon this structure:
class MyBotHandler(object):
'''
A docstring documenting this bot.
'''
def usage(self):
return '''Your description of the bot'''
def handle_message(self, message, bot_handler):
# add your code here
handler_class = MyBotHandler
-
The class name (in this case MyBotHandler) can be defined by you
and should match the name of your bot. To register your bot's class,
adjust the last line handler_class = MyBotHandler
to match your
class name.
-
Every bot needs to implement the functions
usage(self)
handle_message(self, message, bot_handler)
-
These functions are documented in the next section.
Adding a bot to Zulip
Zulip's bot system resides in the python-zulip-api repository.
The structure of the bots ecosystem looks like the following:
zulip_bots
└───zulip_bots
├───bots
│ ├───bot1
│ └───bot2
│ │
│ ├───bot2.py
│ ├───bot2.conf
│ ├───doc.md
│ ├───requirements.txt
│ ├───test_bot2.py
│ ├───assets
│ │ │
│ │ └───pic.png
│ ├───fixtures
│ │ │
│ │ └───test1.json
│ └───libraries
│ │
│ └───lib1.py
├─── lib.py
├─── test_lib.py
├─── run.py
└─── provision.py
Each subdirectory in bots
contains a bot. When writing bots, try to use the structure outlined
above as an orientation.
Testing a bot's output
If you just want to see how a bot reacts to a message, but don't want to set it up on a server,
we have a little tool to help you out: zulip-bot-shell
Example invocations are below:
> zulip-bot-shell converter
Enter your message: "12 meter yard"
Response: 12.0 meter = 13.12336 yard
> zulip-bot-shell -b ~/followup.conf followup
Enter your message: "Task completed"
Response: stream: followup topic: foo_sender@zulip.com
from foo_sender@zulip.com: Task completed
Note that the -b
(aka --bot-config-file
) argument is for an optional third party
config file (e.g. ~/giphy.conf), which only applies to certain types of bots.
Bot API
This section documents functions available to the bot and the structure of the bot's config file.
With this API, you can
- intercept, view, and process messages sent by users on Zulip.
- send out new messages as replies to the processed messages.
With this API, you cannot
- modify an intercepted message (you have to send a new message).
- send messages on behalf of or impersonate other users.
- intercept private messages (except for PMs with the bot as an
explicit recipient).
usage
usage(self)
is called to retrieve information about the bot.
Arguments
- self - the instance the method is called on.
Return values
- A string describing the bot's functionality
Example implementation
def usage(self):
return '''
This plugin will allow users to flag messages
as being follow-up items. Users should preface
messages with "@followup".
Before running this, make sure to create a stream
called "followup" that your API user can send to.
'''
handle_message
handle_message(self, message, bot_handler)
handles user message.
Arguments
-
self - the instance the method is called on.
-
message - a dictionary describing a Zulip message
-
bot_handler - used to interact with the server, e.g. to send a message
Return values
None.
Example implementation
def handle_message(self, message, bot_handler):
original_content = message['content']
original_sender = message['sender_email']
new_content = original_content.replace('@followup',
'from %s:' % (original_sender,))
bot_handler.send_message(dict(
type='stream',
to='followup',
subject=message['sender_email'],
content=new_content,
))
bot_handler.send_message
bot_handler.send_message(message)
will send a message as the bot user. Generally, this is less
convenient than send_reply, but it offers additional flexibility
about where the message is sent to.
Arguments
- message - a dictionary describing the message to be sent by the bot
Example implementation
bot_handler.send_message(dict(
type='stream', # can be 'stream' or 'private'
to=stream_name, # either the stream name or user's email
subject=subject, # message subject
content=message, # content of the sent message
))
bot_handler.send_reply
bot_handler.send_reply(message, response)
will reply to the triggering message to the same place the original
message was sent to, with the content of the reply being response.
Arguments
- message - Dictionary containing information on message to respond to
(provided by
handle_message
).
- response - Response message from the bot (string).
bot_handler.update_message
bot_handler.update_message(message)
will edit the content of a previously sent message.
Arguments
- message - dictionary defining what message to edit and the new content
Example
From zulip_bots/bots/incrementor/incrementor.py
:
bot_handler.update_message(dict(
message_id=self.message_id, # id of message to be updated
content=str(self.number), # string with which to update message with
))
bot_handler.storage
A common problem when writing an interactive bot is that you want to
be able to store a bit of persistent state for the bot (e.g. for an
RSVP bot, the RSVPs). For a sufficiently complex bot, you want need
your own database, but for simpler bots, we offer a convenient way for
bot code to persistently store data.
The interface for doing this is bot_handler.storage
.
The data is stored in the Zulip Server's database. Each bot user has
an independent storage quota available to it.
Since each access to bot_handler.storage
will involve a round-trip
to the server, we recommend writing bots so that they do a single
bot_handler.storage.get
at the start of handle_message
, and a
single bot_handler.storage.put
at the end to submit the state to the
server. We plan to offer a context manager that takes care of this
automatically.
bot_handler.storage.put
bot_handler.storage.put(key, value)
will store the value value
in the entry key
.
Arguments
- key - a UTF-8 string
- value - a UTF-8 string
Example
bot_handler.storage.put("foo", "bar") # set entry "foo" to "bar"
bot_handler.storage.get
bot_handler.storage.get(key)
will retrieve the value for the entry key
.
Arguments
Example
bot_handler.storage.put("foo", "bar")
print(bot_handler.storage.get("foo")) # print "bar"
bot_handler.storage.contains
bot_handler.storage.contains(key)
will check if the entry key
exists.
Arguments
Example
bot_handler.storage.contains("foo") # False
bot_handler.storage.put("foo", "bar")
bot_handler.storage.contains("foo") # True
bot_handler.storage marshaling
By default, bot_handler.storage
accepts any object for keys and
values, as long as it is JSON-able. Internally, the object then gets
converted to an UTF-8 string. You can specify custom data marshaling
by setting the functions bot_handler.storage.marshal
and
bot_handler.storage.demarshal
. These functions parse your data on
every call to put
and get
, respectively.
Configuration file
[api]
key=<api-key>
email=<email>
site=<dev-url>
-
key - the API key you created for the bot; this is how Zulip knows
the request is from an authorized user.
-
email - the email address of the bot, e.g. some-bot@zulip.com
-
site - your development environment URL; if you are working on a
development environment hosted on your computer, use
localhost:9991
Writing tests for bots
Bots, like most software that you want to work, should have unit tests. In this section,
we detail our framework for writing unit tests for bots. We require that bots in the main
python-zulip-api
repository include a reasonable set of unit tests, so that future developers can easily
refactor them.
Unit tests for bots make heavy use of mocking. If you want to get comfortable with mocking,
mocking strategies, etc. you should check out our mocking guide.
A simple example
Let's have a look at a simple test suite for the helloworld
bot.
from zulip_bots.test_lib import StubBotTestCase
class TestHelpBot(StubBotTestCase):
bot_name: str = "helloworld"
def test_bot(self) -> None:
dialog = [
('', 'beep boop'),
('help', 'beep boop'),
('foo', 'beep boop'),
]
self.verify_dialog(dialog)
The helloworld
bot replies with "beep boop" to every message @-mentioning it. We
want our test to verify that the bot actually does that.
Note that our helper method verify_dialog
simulates the conversation for us, and
we just need to set up a list of tuples with expected results.
The best way to learn about bot tests is to read all the existing tests in the
bots
subdirectories.
Testing your test
Once you have written a test suite, you want to verify that everything works as expected.
Advanced testing
This section shows advanced testing techniques for more complicated bots that have
configuration files or interact with third-party APIs.
The code for the bot testing library can be found here.
Testing bots with config files
Some bots, such as Giphy,
support or require user configuration options to control how the bot works.
To test such a bot, you can use the following pattern:
with self.mock_config_info(dict(api_key=12345)):
# self.verify_reply(...)
mock_config_info()
replaces the actual step of reading configuration from the file
system and gives your test "dummy data" instead.
Testing bots with internet access
Some bots, such as Giphy,
depend on a third-party service, such as the Giphy web app, in order to work. Because
we want our test suite to be reliable and not add load to these third-party APIs, tests
for these services need to have "test fixtures": sample HTTP request/response pairs to
be used by the tests. You can specify which one to use in your test code using the
following helper method:
with self.mock_http_conversation('test_fixture_name'):
# self.assert_bot_response(...)
mock_http_conversation(fixture_name)
patches requests.get
and returns the data specified
in the file fixtures/{fixture_name}.json
. Use the following JSON code as a skeleton for new
fixtures:
{
"request": {
"api_url": "http://api.example.com/",
"params": {
}
},
"response": {
},
"response-headers": {
}
}
For an example, check out the giphy bot.
Tip: You can use requestbin or a similar
tool to capture payloads from the service your bot is interacting
with.
Examples
Check out our bots
to see examples of bot tests.
Common problems
Future direction
The long-term plan for this bot system is to allow the same
ExternalBotHandler
code to eventually be usable in several contexts:
- Run directly using the Zulip
call_on_each_message
API, which is
how the implementation above works. This is great for quick
development with minimal setup.
- Run in a simple Python webserver server, processing messages
received from Zulip's outgoing webhooks integration.
- For bots merged into the mainline Zulip codebase, enabled via a
button in the Zulip web UI, with no code deployment effort required.