Spring Boot+Gradle本地K8s环境Tilt构建失败：环境变量解析错误

错误日志 #

STEP 1/3 — Building Custom Build: [supplier-service]
Custom Build: Injecting Environment Variables
  EXPECTED_REF=supplier-service:tilt-build-1679856709
  EXPECTED_IMAGE=library/supplier-service
  EXPECTED_TAG=tilt-build-1679856709
Running cmd: gradlew bootBuildImage --imageName $EXPECTED_REF
> Task :compileJava UP-TO-DATE
> Task :processResources UP-TO-DATE
> Task :classes UP-TO-DATE
> Task :resolveMainClassName UP-TO-DATE
> Task :processAot UP-TO-DATE
> Task :compileAotJava UP-TO-DATE
> Task :processAotResources UP-TO-DATE
> Task :aotClasses UP-TO-DATE
> Task :collectReachabilityMetadata UP-TO-DATE
> Task :bootJar UP-TO-DATE
> Task :bootBuildImage FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':bootBuildImage'.
> Unable to parse image reference "$EXPECTED_REF". Image reference must be in the form '[domainHost:port/][path/]name[:tag][@digest]', with 'path' and 'name' containing only [a-z0-9][.][_][-]

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 7s
9 actionable tasks: 1 executed, 8 up-to-date
gradlew bootBuildImage --imageName $EXPECTED_REF exited with exit code 1

Build Failed: Custom build "gradlew bootBuildImage --imageName $EXPECTED_REF" failed: exit status 1

当前Tiltfile配置 #

# Build
custom_build(
    # Name of the container image
    ref = 'supplier-service',
    # Command to build the container image
    command = 'gradlew bootBuildImage --imageName $EXPECTED_REF',

    # Files to watch that trigger a new build
    deps = ['build.gradle', 'src'],

    live_update = [
        sync('src', '/workspace/BOOT-INF/classes')
    ]
)

# Deploy
k8s_yaml(kustomize('k8s'))

# Manage
k8s_resource('supplier-service', port_forwards=['9001'])

解决方案 #

问题根源 #

Tilt执行custom_build命令时会注入EXPECTED_REF等环境变量，但原配置使用单引号包裹命令，导致shell将$EXPECTED_REF视为字面量字符串，而非环境变量展开，最终bootBuildImage接收到无效的镜像引用字符串$EXPECTED_REF，触发格式错误。

修复方式 #

将custom_build中的command字段改用双引号包裹，让shell正确解析环境变量：

# Build
custom_build(
    ref = 'supplier-service',
    # 改用双引号，确保shell展开$EXPECTED_REF环境变量
    command = "gradlew bootBuildImage --imageName $EXPECTED_REF",
    deps = ['build.gradle', 'src'],
    live_update = [
        sync('src', '/workspace/BOOT-INF/classes')
    ]
)

# Deploy
k8s_yaml(kustomize('k8s'))

# Manage
k8s_resource('supplier-service', port_forwards=['9001'])

替代方案 #

也可以直接使用Tilt的构建ID变量拼接镜像名，避免依赖shell环境变量解析：

import os

# Build
build_id = os.getenv("TILT_BUILD_ID")
custom_build(
    ref = 'supplier-service',
    command = f'gradlew bootBuildImage --imageName supplier-service:tilt-build-{build_id}',
    deps = ['build.gradle', 'src'],
    live_update = [
        sync('src', '/workspace/BOOT-INF/classes')
    ]
)

# Deploy
k8s_yaml(kustomize('k8s'))

# Manage
k8s_resource('supplier-service', port_forwards=['9001'])

内容的提问来源于stack exchange，提问作者Alois Vollmaier