From 90dafb1bed18f4e94b73e54be85436e2f392bed6 Mon Sep 17 00:00:00 2001 From: erlinux <1006990314@qq.com> Date: Thu, 16 Jun 2016 17:17:28 +0800 Subject: [PATCH] erlinux translated --- ... Rapid prototyping with docker-compose.md | 142 ------------------ 1 file changed, 142 deletions(-) delete mode 100644 sources/tech/20160512 Rapid prototyping with docker-compose.md diff --git a/sources/tech/20160512 Rapid prototyping with docker-compose.md b/sources/tech/20160512 Rapid prototyping with docker-compose.md deleted file mode 100644 index 136eff7a7a..0000000000 --- a/sources/tech/20160512 Rapid prototyping with docker-compose.md +++ /dev/null @@ -1,142 +0,0 @@ -Translating by Bestony -Rapid prototyping with docker-compose -======================================== - -In this write-up we'll look at a Node.js prototype for **finding stock of the Raspberry PI Zero** from three major outlets in the UK. - -I wrote the code and deployed it to an Ubuntu VM in Azure within a single evening of hacking. Docker and the docker-compose tool made the deployment and update process extremely quick. - -### Remember linking? - -If you've already been through the [Hands-On Docker tutorial][1] then you will have experience linking Docker containers on the command line. Linking a Node hit counter to a Redis server on the command line may look like this: - -``` -$ docker run -d -P --name redis1 -$ docker run -d hit_counter -p 3000:3000 --link redis1:redis -``` - -Now imagine your application has three tiers - -- Web front-end -- Batch tier for processing long running tasks -- Redis or mongo database - -Explicit linking through `--link` is just about manageable with a couple of containers, but can get out of hand as we add more tiers or containers to the application. - -### Enter docker-compose - -![](http://blog.alexellis.io/content/images/2016/05/docker-compose-logo-01.png) ->Docker Compose logo - -The docker-compose tool is part of the standard Docker Toolbox and can also be downloaded separately. It provides a rich set of features to configure all of an application's parts through a plain-text YAML file. - -The above example would look like this: - -``` -version: "2.0" -services: - redis1: - image: redis - hit_counter: - build: ./hit_counter - ports: - - 3000:3000 -``` - -From Docker 1.10 onwards we can take advantage of network overlays to help us scale out across multiple hosts. Prior to this linking only worked across a single host. The `docker-compose scale` command can be used to bring on more computing power as the need arises. - ->View the [docker-compose][2] reference on docker.com - -### Real-world example: Raspberry PI Stock Alert - -![](http://blog.alexellis.io/content/images/2016/05/Raspberry_Pi_Zero_ver_1-3_1_of_3_large.JPG) ->The new Raspberry PI Zero v1.3 image courtesy of Pimoroni - -There is a huge buzz around the Raspberry PI Zero - a tiny microcomputer with a 1GHz CPU and 512MB RAM capable of running full Linux, Docker, Node.js, Ruby and many other popular open-source tools. One of the best things about the PI Zero is that costs only 5 USD. That also means that stock gets snapped up really quickly. - -*If you want to try Docker or Swarm on the PI check out the tutorial below.* - ->[Docker Swarm on the PI Zero][3] - -### Original site: whereismypizero.com - -I found a webpage which used screen scraping to find whether 4-5 of the most popular outlets had stock. - -- The site contained a static HTML page -- Issued one XMLHttpRequest per outlet accessing /public/api/ -- The server issued the HTTP request to each shop and performed the scraping - -Every call to /public/api/ took 3 seconds to execute and using Apache Bench (ab) I was only able to get through 0.25 requests per second. - -### Reinventing the wheel - -The retailers didn't seem to mind whereismypizero.com scraping their sites for stock, so I set about writing a similar tool from the ground up. I had the intention of handing a much higher amount of requests per second through caching and de-coupling the scrape from the web tier. Redis was the perfect tool for the job. It allowed me to set an automatically expiring key/value pair (i.e. a simple cache) and also to transmit messages between Node processes through pub/sub. - ->Fork or star the code on Github: [alexellis/pi_zero_stock][4] - -If you've worked with Node.js before then you will know it is single-threaded and that any CPU intensive tasks such as parsing HTML or JSON could lead to a slow-down. One way to mitigate that is to use a second worker process and a Redis messaging channel as connective tissue between this and the web tier. - -- Web tier - -Gives 200 for cache hit (Redis key exists for store) - -Gives 202 for cache miss (Redis key doesn't exist, so issues message) - -Since we are only ever reading a Redis key the response time is very quick. -- Stock Fetcher - -Performs HTTP request - -Scrapes for different types of web stores - -Updates a Redis key with a cache expire of 60 seconds - -Also locks a Redis key to prevent too many in-flight HTTP requests to the web stores. -``` -version: "2.0" -services: - web: - build: ./web/ - ports: - - "3000:3000" - stock_fetch: - build: ./stock_fetch/ - redis: - image: redis -``` - -*The docker-compose.yml file from the example.* - -Once I had this working locally deploying to an Ubuntu 16.04 image in the cloud (Azure) took less than 5 minutes. I logged in, cloned the repository and typed in `docker compose up -d`. That was all it took - rapid prototyping a whole system doesn't get much better. Anyone (including the owner of whereismypizero.com) can deploy the new solution with just two lines: - -``` -$ git clone https://github.com/alexellis/pi_zero_stock -$ docker-compose up -d -``` - -Updating the site is easy and just involves a `git pull` followed by a `docker-compose up -d` with the `--build` argument passed along. - -If you are still linking your Docker containers manually, try Docker Compose for yourself or my code below: - ->Fork or star the code on Github: [alexellis/pi_zero_stock][5] - -### Check out the test site - -The test site is currently deployed now using docker-compose. - ->[stockalert.alexellis.io][6] - -![](http://blog.alexellis.io/content/images/2016/05/Screen-Shot-2016-05-16-at-22-34-26-1.png) - -Preview as of 16th of May 2016 - ----------- -via: http://blog.alexellis.io/rapid-prototype-docker-compose/ - -作者：[Alex Ellis][a] -译者：[译者ID](https://github.com/译者ID) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]: http://blog.alexellis.io/author/alex/ -[1]: http://blog.alexellis.io/handsondocker -[2]: https://docs.docker.com/compose/compose-file/ -[3]: http://blog.alexellis.io/dockerswarm-pizero/ -[4]: https://github.com/alexellis/pi_zero_stock -[5]: https://github.com/alexellis/pi_zero_stock -[6]: http://stockalert.alexellis.io/ -