After several iterations with code and experiments with body positions, here’s the final version of the Quadropod for your judgement. Controlled over Bluetooth with a general purpose controller Android app.
Let me know what you think.
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Подключаем очередь сообщений к Flask-приложению под управлением Gunicorn
Один из возможных подходов к построению микросервисных приложений состоит в организации общения сервисов между собой посредством шины сообщений. Такая архитектура называется “Event-driven architecture”. Её преймущество в слабой связности компонентов. В этой небольшой статье я делюсь методом добавления интеграции с шиной на основе RabbitMQ в приложение, написанное на Flask.
Меняем KrakenD на OpenResty
В предыдущем посте я писал о выборе API шлюза и как KrakenD позволил нам склеивать ответы от различных API. В итоге мы отказались от KrakenD в пользу OpenResty и я расскажу почему.
Merging responses in KrakenD
KrakenD is exciting. Among all different features there’s one tech that’s particularly interesting and helpful. It’s possible to define an endpoint that calls several underlying services (either sequentially or concurrently) and merges the responses.
When it’s sequential calling, it even lets you use the data returned from the previous calls in the following. However, at the moment of writing (KrakenD 2.0.5) it’s limited to using JSON field values as parts of the request path only. You cannot compose bodies of following requests using this data declaratively.
Choosing API Gateway
Recently we’ve started working on an experimental internal project based on microservices principles. We’ve broken down our application into contexts using several event storming sessions, defined events, commands and aggregates. When it all took shape, we sat and started working on services.
Two months into development I went talking to the frontend team only to find that they would be more than happy to see a single entry point into API.
Scripted sorting in Elasticsearch
In some of our projects where we need flexible fuzzy search capabilities with weighted results we use Elasticsearch. It indexes everything you throw at it, then gives you tools to search it flexibly.
In this short article I share the approach we used to sort the weighted output additionally basing on certain criteria.
Introducing HiDoq
IMPORTANT UPDATE
P2P Telehealth has been rebranded as HiDoq. At the moment we have several servers working with clients in the following regions:
Earlier this year together with two partners we started a small company to work on P2P Telehealth – easy to use, compliant and secure telehealth platform. It’s like Zoom or Skype, but for health providers, clinics and their patients.
Anyone with no technical background should be able to join the consultation in seconds. No new apps needed. I think we succeeded.
Quadropod - Mission completed
Quadropod - The library
Today I focused on several things:
- Converted functional code into classes
- Extracted general purpose pieces like the driver and the module to prepare move sequence buffers into a library
- Built the rest of the custom code on top of it
- Made the bot go back a step
- Made an improvement to how the step is made which increased precision
- Updated calculations to take the base piece length into account. Next comes turning, and this will become handy.
Quadropod - Rework complete
Rework of the code is complete. Now it’s completely based on the timer interrupt. I must admit, it’s a huge difference in the way motion feels and is programmed. The level of control over what happens and when is tremendous. Exciting!
Quadropod - Switching to interrupts and timers
After a bit of experimentation I finally figured that working with servos from the main program loop is not very efficient and precise. The main issue I’ve been facing is synchronous and controlled rotation of several servos to different angles.