Docker容器中的并行代码执行 [英] Parallel code execution in Docker containers

问题描述

我有一个脚本，可以按URLslist抓取数据。
该脚本正在docker容器中执行。
我想在多个实例中运行它，例如20。
为此，我想使用 docker-compose scale worker = 20 并向每个实例传递INDEX，以便脚本知道应删除哪些URL。

I have a script that scrapes data by URLslist. This script is executing in a docker container. I would like to run it in multiple instances, for example, 20. For that, I wanted to use docker-compose scale worker=20 and to pass the INDEX to each instance so that the script knows which URLs should be scrapped.

示例。

ID, URL
0 https://example.org/sdga2
1 https://example.org/fsdh34
2 https://example.org/fs4h35
3 https://example.org/f1h36
4 https://example.org/fs4h37
...

如果存在3个实例，脚本的第一个实例应处理一个URL，其ID等于0、3、6、9，即ID = INDEX + INSTANCES_NUM * k。

If there are 3 instances, 1st instance of script should process a url whose ID equals to 0, 3, 6, 9 i.e. ID = INDEX + INSTANCES_NUM * k.

我不知道如何将INDEX传递给在Docker容器中运行的脚本。
当然，我可以在docker-compose.yml中使用环境变量中的不同INDEX复制服务。但是，如果实例数大于10，甚至大于50，将是一个非常糟糕的解决方案）

I don't know how to pass INDEX to script running in Docker container. Of course, I can duplicate services in docker-compose.yml with different INDEX in environment vars. But if instances number is greater 10 or even 50 it will be a very bad solution)

有人知道怎么做吗？

推荐答案

使用 docker-compose ，我不认为对此有任何支持。但是，在可以使用类似撰写文件的群集模式下，您可以使用 {{.Task.Slot}} 作为环境变量进行传递： //docs.docker.com/engine/reference/commandline/#create-services-using-templates rel = nofollow noreferrer>服务模板。例如，

With docker-compose, I don't believe there's any support for this. However, with swarm mode, which can use a similar compose file, you can pass {{.Task.Slot}} as an environment variable using service templates. E.g.

version: '3'
services:
  test:
    image: busybox
    command: /bin/sh -c "echo My task number is $$task_id && tail -f /dev/null"
    environment:
      task_id: "{{.Task.Slot}}"
    deploy:
      replicas: 5

而不是 docker-compose up ，我使用 docker stack deploy进行部署-c docker-compose.yml test 。我的本地群集集群只是使用 docker swarm init 创建的单个节点。

Instead of docker-compose up, I deploy with docker stack deploy -c docker-compose.yml test. My local swarm cluster is just a single node created with docker swarm init.

然后，检查每个运行的群集容器：

Then, reviewing each of these running containers:

$ docker ps --filter label=com.docker.swarm.service.name=test_test
CONTAINER ID        IMAGE               COMMAND                  CREATED              STATUS              PORTS               NAMES
ccd0dbebbcbe        busybox:latest      "/bin/sh -c 'echo My…"   About a minute ago   Up About a minute                       test_test.3.i3jg6qrg09wjmntq1q17690q4
bfaa22fa3342        busybox:latest      "/bin/sh -c 'echo My…"   About a minute ago   Up About a minute                       test_test.5.iur5kg6o3hn5wpmudmbx3gvy1
a372c0ce39a2        busybox:latest      "/bin/sh -c 'echo My…"   About a minute ago   Up About a minute                       test_test.4.rzmhyjnjk00qfs0ljpfyyjz73
0b47d19224f6        busybox:latest      "/bin/sh -c 'echo My…"   About a minute ago   Up About a minute                       test_test.1.tm97lz6dqmhl80dam6bsuvc8j
c968cb5dbb5f        busybox:latest      "/bin/sh -c 'echo My…"   About a minute ago   Up About a minute                       test_test.2.757e8evknx745120ih5lmhk34

$ docker ps --filter label=com.docker.swarm.service.name=test_test -q | xargs -n 1 docker logs
My task number is 3
My task number is 5
My task number is 4
My task number is 1
My task number is 2

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