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Python 3 microservice library / framework using asyncio with HTTP, websockets, RabbitMQ / AMQP and AWS SNS+SQS support.

Project description

tomodachi - a lightweight microservices framework with asyncio

Python 3 microservice framework using asyncio (async / await) with HTTP, websockets, RabbitMQ / AMQP and AWS SNS+SQS support for event bus based communication.

Tomodachi is a tiny framework designed to build fast microservices listening on HTTP or communicating over event driven message buses like RabbitMQ, AMQP, AWS (Amazon Web Services) SNS+SQS, etc. It’s designed to be extendable to make use of any type of transport layer available.

Tomodachi (友達) means friends – and since microservices wouldn’t make sense on their own I think they need to be friends with each other. 😻 👬 👭 👫

How do I use this?

Installation via pip 🌮

local ~$ pip install tomodachi

Basic HTTP based service 🌟

import tomodachi

class Service(object):
    name = 'example'

    # Request paths are specified as regex for full flexibility
    @tomodachi.http('GET', r'/resource/(?P<id>[^/]+?)/?')
    async def resource(self, request, id):
        # Returning a string value normally means 200 OK
        return 'id = {}'.format(id)

    @tomodachi.http('GET', r'/health')
    async def health_check(self, request):
        # Return can also be a tuple, dict or even an aiohttp.web.Response
        # object for more complex responses - for example if you need to
        # send byte data, set your own status code or define own headers
        return {
            'body': 'Healthy',
            'status': 200

    # Specify custom 404 catch-all response
    async def error_404(self, request):
        return 'error 404'

Run the service 😎

# if installed via pip
$ tomodachi run

# if cloned from repo
$ python run
October 02, 2017 - 13:38:00,481516
Quit services with <ctrl+c>.
2017-10-02 13:38:01,234 (services.service): Initializing service "example" [id: <uuid>]
2017-10-02 13:38:01,248 (transport.http): Listening [http] on
2017-10-02 13:38:01,248 (services.service): Started service "example" [id: <uuid>]
$ curl -v ""
< HTTP/1.1 200 OK
< Content-Type: text/plain; charset=utf-8
< Server: tomodachi
< Content-Length: 9
< Date: Mon, 02 Oct 2017 13:38:02 GMT
id = 1234

Requirements 👍

License 🙋

Offered under the MIT license

Source code 🦄

The latest developer version of tomodachi is available at the GitHub repo

Any questions?

What is the best way to run a tomodachi service?
There is no way to tell you how to orchestrate your infrastructure. Some people may run it containerized in a Docker environment, deployed via Terraform and some may run several services on the same environment, on the same machine. There are no standards and we’re not here to tell you about your best practices.
Are there any more example services?
There are a few examples in the examples folder, including examples to publish events/messages to an AWS SNS topic and subscribe to an AWS SQS queue. There’s also a similar example of how to work with pub-sub for RabbitMQ via AMQP transport protocol.
Why should I use this?
I’m not saying you should, but I’m not saying you shouldn’t. tomodachi is a perfect place to start when experimenting with your architecture or trying out a concept for a new service. It may not have all the features you desire and it may never do.
Should I run this in production?
It’s all still highly experimental and it depends on other experimental projects, so you have to be in charge here and decide for yourself. Let me know if you do however!
Who built this and why?
My name is Carl Oscar Aaro and I’m a coder from Sweden. I simply wanted to learn more about asyncio and needed a constructive off-work project to experiment with – and here we are. 🎉


0.9.0 (2018-03-04)

  • Updated to use aiohttp 3.X.X+ and aiobotocore 0.6.X+.
  • Dropped support for Python versions below 3.5.3 as new aiohttp requires at least Python 3.5.3. Last version with support for Python 3.5.0, 3.5.1 and 3.5.2 is tomodachi 0.8.X series.

0.8.3 (2018-03-02)

  • Print stack trace for outputs from schedule invoker functions tasks instead of silently catching exceptions.
  • Handle close and receive errors for websockets and cleanly close already opened websockets on service exit.

0.8.2 (2018-02-28)

  • Fixed broken HTTP transports due to missing colorama import.

0.8.1 (2018-02-27)

  • Correction for README in 0.8.X release.

0.8.0 (2018-02-27)

  • It’s now possible to specify queue_name on AWS SNS+SQS and AMQP decorators for competing queues. If not specified an automatically generated hash will be used as queue name as it worked previously.
  • Fixes an issue with relative imports from within service files, which resulted in “SystemParent module ‘’ not loaded, cannot perform relative import” or “ImportError: attempted relative import with no known parent package”. (github: 0x1EE7)
  • Exceptions that are subclasses of AmqpInternalServiceError and AWSSNSSQSInternalServiceError will now also work in the same way, resulting in the messages to be retried when raised.
  • Service classes now have built in log functions for setting up logging to file as well as logging. They are self.log_setup('logname', level, filename) and self.log('logname', level, message).
  • HTTP services will have their access log color coded when outputting to nothing else than stdout, which should be helpful in an overview during development.

0.7.0 (2018-01-27)

  • Added @websocket as a decorator type for handling websockets. A function call should return two callables which will be used for receiving messages through the socket and as a way to notify about the closure of the socket.

0.6.5 (2018-01-16)

  • Updated aiohttp to latest version which solves incompabilities with yarl.

0.6.4 (2018-01-15)

  • Added a stricter dependency check for yarl.

0.6.3 (2018-01-12)

  • Gracefully handle exceptions thrown when receiving messages from AWS SNS+SQS. For example when invalid XML data in response which causes botocore to throw a botocore.parsers.ResponseParserError.
  • Updated dependencies to allow for newer version of aiohttp 2.3.X.
  • Improved type hinting.

0.6.2 (2017-11-15)

  • Recreate queues and resubscribe to topics if queue is removed during runtime.

0.6.1 (2017-11-15)

  • Introduced new options for AWS SNS/SQS transport to use aws_endpoint_urls for sns and sqs if the user wishes to connect to other endpoints and the actual AWS endpoints, which could be useful for development and testing. The AWS SNS/SQS examples has been updated with values to reflect these options.
  • Reworked timeouts and reconnects and fixed an issue in the recreate_client method which was called on server disconnects.

0.6.0 (2017-11-15)

  • Stricter version control of required packages to not break installation on major/minor related updates.
  • Updates to support aiohttp 2.3.X and aiobotocore 0.5.X.

0.5.3 (2017-11-08)

  • Corrects issues on timeouts and server disconnects.
  • Specify fixed version for aiohttp to not break installation.
  • Code cleanup to conform with pycodestyle.

0.5.2 (2017-10-08)

  • Add argument option for log level as ‘-l’ or ‘–log’. (github: djKooks)
  • Better matching of imported modules on hot-reload which will cause reloading into code with syntax errors or indentation errors much harder.

0.5.1 (2017-10-03)

  • More improvements regarding hot-reloading of code that may have syntax errors, indentation errors or issues when the service is being initiated.

0.5.0 (2017-10-02)

  • Solves the issue where hot-loading into a state where the code errors due to syntax errors would crash the application, making the user need to manually restart the process.

0.4.10 (2017-10-02)

  • Fixes for failing tests on hot-reloading during test phase.

0.4.9 (2017-10-02)

  • Solves issue with Segmentation fault in Python 3.6 during hot-reload on Linux.

0.4.8 (2017-10-02)

  • Fixes type hinting issues with Python 3.5.1.

0.4.7 (2017-09-30)

  • Reworked watcher since it ended up using 90% CPU of the running core due to constant re-indexing (mstat) of every file every 0.5s. Full re-index will now only run every 10 seconds, since it’s more rare that new files are added than existing files edited. Watcher for edited existing files will still run at the same intervals.
  • Watched file types may now be specified via configuration via options.watcher.watched_file_endings.

0.4.6 (2017-09-29)

  • Messages via SNS+SQS or AMQP over 60000 bytes as JSON will now be sent in a gzipped base64 encoded format to allow for larger limits and lower potential SNS costs due to multiplexed messaging.
  • Fixes an issue with multidict 3.2.0 on hot-reload which made the tomodachi application crash.

0.4.5 (2017-09-07)

  • Possibility to requeue messages that result in specific exceptions. Exceptions that will nack the message (for AMQP transport) is called AmqpInternalServiceError. Exceptions that won’t delete the message from the queue and in turn will result in it to “reappear” unless configured non-default (for AWS SNS+SQS transport) is called AWSSNSSQSInternalServiceError.

0.4.4 (2017-08-25)

  • Corrected an issue regarding crontab notation for scheduling function calls where it didn’t parse the upcoming date correctly if both isoweekday and day part were given.

0.4.3 (2017-08-09)

  • Catches unintended HTTP exceptions and prints a useful stacktrace if log_level is set to DEBUG.

0.4.2 (2017-08-07)

  • Fixes an issue where Content-Type header couldn’t be specified without charset in HTTP transports.
  • Cleared some old debug code.

0.4.1 (2017-08-05)

  • Corrects and issue with AMQP transport which caused invoked functions to not be able to declare scope variables without crashes.

0.4.0 (2017-08-05)

  • Release fixes a major issue which caused invoked functions to not be able to declare any scope variables.
  • @http_static decorator for serving static files from a folder on disk. Takes to values; 1. the path to the folder, either relative to the service file or absolute; 2. the base URL path for static files as a regexp.

0.3.0 (2017-07-25)

  • Changed format of access log for HTTP requests - now logging user agent and login name (if authorization via Basic Auth).
  • Support for X-Forwarded-For headers via real_ip_from and real_ip_header options which will log the forwarded IP instead of the one from the load balancer / proxy.
  • Access log for HTTP can now be specified as a filename to which the service will log all requests.
  • Fixes issue with schedule invoker which would crash if invoked at second 0.
  • Updated dependencies to latest available versions.

0.2.17 (2017-07-05)

  • Timezone support for schedule invoker functions.
  • Added more decorator invoker functions as aliases for common scheduler use cases - @minutely, @hourly, @daily and @heartbeat (every second)
  • Updated example services and better test cases.
  • Updated aiohttp / aiobotocore / botocore dependencies.

0.2.16 (2017-07-02)

  • Solved issues with aiobotocore / aiohttp dependencies.
  • Refactored loader functions.

0.2.15 (2017-07-02)

  • Corrected issue with configuration values for AWS and AWS SNS+SQS settings.
  • Improved testing suite and more code coverage for integration tests.

0.2.14 (2017-06-30)

  • New “transport” invoker for service functions: schedule. It works like cron type scheduling where specific functions will be run on the specified interval. For example a function can be specified to run once per day at a specific time or every second minute, or the last Tuesday of January and March at 05:30 AM.
  • Values for keyword arguments invoked by transport decorators were earlier always set to None, despite having other default values. This is now corrected.

0.2.13 (2017-06-20)

  • Type hinted examples and test cases.
  • Shielded function calls for AMQP and SNS+SQS transports to avoid unexpected execution stop.
  • Added version output to tomodachi CLI tool.
  • Additional test cases.

0.2.12 (2017-06-18)

  • Type hinted code base and minor bug fixes for internal functions.

0.2.11 (2017-06-09)

  • Invoker methods can now be called directly without the need to mock the invoker decorator function.

0.2.10 (2017-06-08)

  • Added @functools.wraps decorator to invoked functions of service classes.

0.2.9 (2017-06-06)

  • Added a list of safe modules that may never be removed from the list of already loaded modules. Removing the module ‘typing’ from the list would cause a RecursionError exception since Python 3.6.1.

0.2.8 (2017-05-23)

  • Additional improvements to network connectivity issues to not get stuck in waiting state.

0.2.7 (2017-05-23)

  • Improved SNS+SQS draining / restart when network connectivity has been lost or temporarily suspended. Would improve situations when development machine has been in hibernation.
  • Replaced deprecated logging functions to rid warnings.

0.2.6 (2017-05-22)

  • Support for a “generic” aws dictonary in options that can hold region, access key id and secret to be shared among other AWS resources/services.
  • Updated aiobotocore / botocore dependencies.
  • Gracefully handle and discard invalid SNS/SQS messages not in JSON format.
  • Corrected issue where watched directories with “similar” names as settings would be ignored.

0.2.5 (2017-05-16)

  • Updated issues with function caching due to keepalive when hot reloading in development. Currently disables keepalive entirely.
  • Fixed issue with updated file logging for watcher.

0.2.4 (2017-05-12)

  • Downgraded botocore to meet requirements and to make the installed tomodachi script runnable again.

0.2.3 (2017-05-10)

  • Watcher is now configurable to ignore specific directories dependant on the service. (github: smaaland)
  • Fixed issue where using --config instead of -c would result in a raised exception. (github: smaaland)

0.2.2 (2017-05-04)

  • tomodachi.transport.http has its own Response object that works better with default content types and charsets - examples/ updated.
  • No automatic conversion will be tried if the returned response of an http method is of bytes type.

0.2.1 (2017-05-03)

  • Improved handling of how charsets and encodings work with aiohttp.
  • Fixed an issue where Content-Type header would always be included twice for aiohttp.web.Response objects.

0.2.0 (2017-05-02)

  • Watcher now only reacts to files with file endings .py, .json, .yml, .html or .html and ignores to look at paths __pycache__, .git, .svn, __ignored__, __temporary__ and __tmp__.
  • HTTP transport may now respond with an aiohttp.web.Response object for more complex responses.
  • HTTP transport response headers can now use the multidict library.

0.1.11 (2017-04-02)

  • Working PyPI release.
  • Added unit tests.
  • Works with aiohttp 2 and aiobotocore 0.3.
  • Service classes must be decorated with @tomodachi.service.

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