python - 如何通过运行 Fargate ECS 任务查看 Python 打印语句？

Question

我有一个 Fargate ECS 容器，用于通过 ECS 中的任务运行 Docker 容器。当任务开始时，会调用一个 sh 脚本， runner.sh ，

#!/bin/sh
echo "this line will get logged to ECS..."
python3 src/my_python_script.py # however print statements from this Python script are not logged to ECS

这又会启动一个长时间运行的 Python 脚本 my_python_script.py 。我知道 Python 脚本运行良好，因为它完成了它需要做的事情，但我看不到 Python 脚本的输出。
在 my_python_script.py 内部有几个 print() 语句。在我的 ECS Fargate 任务的 CloudWatch 日志中，我看到了 sh 脚本 ( "this line will get logged to ECS..." ) 的输出，但没有看到 Python 脚本中生成的 print() 语句的输出。
这是我的任务定义中的日志配置:

{
    "ipcMode": null,
    "executionRoleArn": "myecsTaskExecutionRolearn",
    "containerDefinitions": [
        {
            "dnsSearchDomains": null,
            "environmentFiles": null,
            "logConfiguration": {
                "logDriver": "awslogs",
                "secretOptions": null,
                "options": {
                    "awslogs-group": "/ecs/mylogsgroup",
                    "awslogs-region": "eu-west-1",
                    "awslogs-stream-prefix": "ecs"
                }
            },
            "entryPoint": null,
            "portMappings": [],
            "command": null,
            "linuxParameters": null,
            "cpu": 0,
            "environment": [],
            "resourceRequirements": null,
            "ulimits": null,
            "dnsServers": null,
            "mountPoints": [],
            "workingDirectory": null,
            "secrets": null,
            "dockerSecurityOptions": null,
            "memory": null,
            "memoryReservation": null,
            "volumesFrom": [],
            "stopTimeout": null,
            "image": "1234567.dck.aws.com/mydockerimage",
            "startTimeout": null,
            "firelensConfiguration": null,
            "dependsOn": null,
            "disableNetworking": null,
            "interactive": null,
            "healthCheck": null,
            "essential": true,
            "links": null,
            "hostname": null,
            "extraHosts": null,
            "pseudoTerminal": null,
            "user": null,
            "readonlyRootFilesystem": null,
            "dockerLabels": null,
            "systemControls": null,
            "privileged": null,
            "name": "my-task-definition-name"
        }
    ],
    "memory": "4096",
    "taskRoleArn": "myecsTaskRolearn",
    "family": "my-task-definition-name",
    "pidMode": null,
    "requiresCompatibilities": [
        "FARGATE"
    ],
    "networkMode": "awsvpc",
    "cpu": "2048",
    "inferenceAccelerators": [],
    "proxyConfiguration": null,
    "volumes": [],
    "tags": []
}

Dockerfile:

FROM rocker/verse:3.6.0
ENV DEBIAN_FRONTEND noninteractive

RUN install2.r --error \
    jsonlite

RUN echo "deb http://ftp.de.debian.org/debian testing main" >> /etc/apt/sources.list
RUN echo 'APT::Default-Release "stable";' | tee -a /etc/apt/apt.conf.d/00local
RUN apt-get update && apt-get -t testing install -y --force-yes python3.6
RUN apt-get update && apt-get -t testing install -y libmagick++-dev python3-pip python-setuptools 

RUN mkdir /app
WORKDIR /app
COPY ./src /app/src

RUN pip3 install --trusted-host pypi.python.org -r /app/requirements.txt

CMD /app/runner.sh

我想我正在遵循 https://docs.aws.amazon.com/AmazonECS/latest/userguide/using_awslogs.html 的 awslogs 说明，但也许不是？我是否需要做一些明显的事情来确保 Python 脚本中的 print() 语句被捕获到我的 ECS 任务的 CloudWatch 日志中？

Answer 1

在我看来，您可以在这里处理几件事。
第一个是 Python 的默认缓冲行为，这可能会阻止输出显示。您将需要停止此操作。
您可以设置 PYTHONUNBUFFERED通过在 CMD 之前插入以下内容来正确设置 env var:ENV PYTHONUNBUFFERED=1其次，引自Using the awslogs driver您链接的文档:

The type of information that is logged by the containers in your task depends mostly on their ENTRYPOINT command. By default, the logs that are captured show the command output that you would normally see in an interactive terminal if you ran the container locally, which are the STDOUT and STDERR I/O streams. The awslogs log driver simply passes these logs from Docker to CloudWatch Logs. For more information on how Docker logs are processed, including alternative ways to capture different file data or streams, see View logs for a container or service in the Docker documentation.

因此，按照 the Exec form of ENTRYPOINT，我将用以下内容替换 CMD 行: ENTRYPOINT ["/app/runner.sh"]这应该用于为您的 shell 脚本连接 STDOUT 和 STDERR I/O 流，并希望将您的 Python 脚本连接到容器日志记录。