用自定义执行器使用 LXD

在这个例子中，我们使用 LXD 为每个构建创建容器，过后再进行清理。

这个例子中每个阶段都使用 Bash 脚本。您可以指定您自己的镜像，会展示为 CI_作业镜像。出于简单考虑，这个例子使用 ubuntu:18.04 镜像。如果想支持多个镜像，您需要修改执行器。

这些脚本拥有以下先决条件：

配置

[[runners]]
  name = "lxd-driver"
  url = "https://jihulab.com"
  token = "xxxxxxxxxxx"
  executor = "custom"
  builds_dir = "/builds"
  cache_dir = "/cache"
  [runners.custom]
    prepare_exec = "/opt/lxd-driver/prepare.sh" # Path to a bash script to create lxd container and download dependencies.
    run_exec = "/opt/lxd-driver/run.sh" # Path to a bash script to run script inside the container.
    cleanup_exec = "/opt/lxd-driver/cleanup.sh" # Path to bash script to delete container.

基础

准备、运行和清理阶段都会用到这个脚本，用以生成脚本需要用到的变量。

很重要的一点是，这个脚本和其他脚本所在的目录相同，也就是 /opt/lxd-driver/。

#!/usr/bin/env bash

# /opt/lxd-driver/base.sh

CONTAINER_ID="runner-$CUSTOM_ENV_CI_RUNNER_ID-project-$CUSTOM_ENV_CI_PROJECT_ID-concurrent-$CUSTOM_ENV_CI_CONCURRENT_PROJECT_ID-$CUSTOM_ENV_CI_JOB_ID"

准备

准备脚本会进行以下操作：

如果已经有一个正在运行中，则销毁拥有同样名称的容器。
启动容器并等待。
安装先决条件依赖项。

#!/usr/bin/env bash

# /opt/lxd-driver/prepare.sh

currentDir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
source ${currentDir}/base.sh # Get variables from base.

set -eo pipefail

# trap any error, and mark it as a system failure.
trap "exit $SYSTEM_FAILURE_EXIT_CODE" ERR

start_container () {
    if lxc info "$CONTAINER_ID" >/dev/null 2>/dev/null ; then
        echo 'Found old container, deleting'
        lxc delete -f "$CONTAINER_ID"
    fi

    # The container image is hardcoded, but you can use
    # the `CI_JOB_IMAGE` predefined variable
    # https://docs.gitlab.com/ee/ci/variables/predefined_variables.html
    # which is available under `CUSTOM_ENV_CI_JOB_IMAGE` to allow the
    # user to specify the image. The rest of the script assumes that
    # you are running on an ubuntu image so modifications might be
    # required.
    lxc launch ubuntu:18.04 "$CONTAINER_ID"

    # Wait for container to start, we are using systemd to check this,
    # for the sake of brevity.
    for i in $(seq 1 10); do
        if lxc exec "$CONTAINER_ID" -- sh -c "systemctl isolate multi-user.target" >/dev/null 2>/dev/null; then
            break
        fi

        if [ "$i" == "10" ]; then
            echo 'Waited for 10 seconds to start container, exiting..'
            # Inform GitLab Runner that this is a system failure, so it
            # should be retried.
            exit "$SYSTEM_FAILURE_EXIT_CODE"
        fi

        sleep 1s
    done
}

install_dependencies () {
    # Install Git LFS, git comes pre installed with ubuntu image.
    lxc exec "$CONTAINER_ID" -- sh -c 'curl -s "https://packagecloud.io/install/repositories/github/git-lfs/script.deb.sh" | sudo bash'
    lxc exec "$CONTAINER_ID" -- sh -c "apt-get install -y git-lfs"

    # Install gitlab-runner binary since we need for cache/artifacts.
    lxc exec "$CONTAINER_ID" -- sh -c 'curl -L --output /usr/local/bin/gitlab-runner "https://gitlab-runner-downloads.gitlab.cn/latest/binaries/gitlab-runner-linux-amd64"'
    lxc exec "$CONTAINER_ID" -- sh -c "chmod +x /usr/local/bin/gitlab-runner"
}

echo "Running in $CONTAINER_ID"

start_container

install_dependencies

运行

系统会通过 STDIN 向容器发送脚本内容，运行极狐GitLab Runner 生成的脚本。

#!/usr/bin/env bash

# /opt/lxd-driver/run.sh

currentDir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
source ${currentDir}/base.sh # Get variables from base.

lxc exec "$CONTAINER_ID" /bin/bash < "${1}"
if [ $? -ne 0 ]; then
    # Exit using the variable, to make the build as failure in GitLab
    # CI.
    exit $BUILD_FAILURE_EXIT_CODE
fi

清理

因为构建已经结束，所以会销毁容器。

#!/usr/bin/env bash

# /opt/lxd-driver/cleanup.sh

currentDir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
source ${currentDir}/base.sh # Get variables from base.

echo "Deleting container $CONTAINER_ID"

lxc delete -f "$CONTAINER_ID"