如何在執行Gradle任務的依賴關係之前做些事情？

Question

我在build.gradle如下：

task aoeu << { 
    println "**************************** during" 
} 

tasks.publish.dependsOn(aoeu) 

tasks.publish.doFirst { 
    println "************************* before" 
} 

tasks.publish.doLast { 
    println "************************* after" 
} 

它的輸出是：

:aoeu 
**************************** during 
:publish 
************************* before 
************************* after 

但我真正需要的是爲「中」到「前」和「後」之間發生。如何才能做到這一點？ 「發佈」應該依賴於「之前」嗎？如果是這樣，我怎麼能保證它發生在其他依賴之前？

Answer 1

task snth << { 
    println "************************* before" 
} 

task aoeu << { 
    println "**************************** during aoeu" 
} 
publish.dependsOn(aoeu) 

task ueoa << { 
    println "**************************** during ueoa" 
} 
publish.dependsOn(ueoa) 

publish.doLast { 
    println "************************* after" 
} 

publish.dependsOn.each { dependency -> 
    if (dependency instanceof Task) { 
     dependency.dependsOn(aoeu) 
    } 
} 

將輸出：

:snth 
************************* before 
:aoeu 
**************************** during aoeu 
:ueoa 
**************************** during ueoa 
:publish 
************************* after 

如果你想添加的依賴遞歸：

def recursivelyAddDependsOn(Task parent, Task dependsOn) { 
    if (!parent.equals(dependsOn)) { 
     parent.dependsOn(dependsOn) 

     def tasks = parent.dependsOn.findAll { dependency -> 
      dependency instanceof Task 
     } 
     tasks.each { task -> 
      recursivelyAddDependsOn(task, dependsOn) 
     } 
    } 
} 

recursivelyAddDependsOn(publish, snth) 

而更多功能的解決方案是：

def recursivelyApplyToTaskDependencies(Task parent, Closure closure) { 
    closure(parent) 

    parent.dependsOn.findAll { dependency -> 
     dependency instanceof Task 
    }.each { task -> 
     recursivelyApplyToTaskDependencies(task, closure) 
    } 
} 

def recursivelyAddTaskDependency(Task parent, Task dependency) { 
    def addTaskDependency = { p -> 
     if (!p.name.equals(dependency.name)) { 
      p.dependsOn(dependency) 
     } 
    } 

    recursivelyApplyToTaskDependencies(parent, addTaskDependency) 
} 

recursivelyAddTaskDependency(publish, snth) 

Answer 2

據我所知，你的代碼應該可以正常工作，但它不會。應在0​​（執行階段）之前運行的配置階段執行 doFirst。 BTW這個代碼工作正常：

彼得Niederwiser寫到這裏https://stackoverflow.com/a/9204159/2069368doFirst運行在執行階段的第一條語句（doLast之前），這樣您的代碼工作正常。這個例子會告訴你執行順序gradle這個編譯：

task publish { 
    println "(1) before (run in configuration phase)" // this will run before gradle dependencies 
} 

task aoeu << { 
    println "(2) during (run in execution phase as last statement)" 
} 

tasks.publish.dependsOn(aoeu) 
tasks.publish.doLast { 
    println "(4) after (run in execution phase as last statement)" 
} 

tasks.publish.doFirst { 
    println "(3) after (run in execution phase as FORST statement - before doLast/<<)" 
} 

它將返回

C:\>gradle publish 
(1) before (run in configuration phase) 
:aoeu 
(2) during (run in execution phase as last statement) 
:publish 
(3) after (run in execution phase as FORST statement - before doLast/<<) 
(4) after (run in execution phase as last statement) 

[更新]

這裏http://gradle.1045684.n5.nabble.com/task-run-order-lt-lt-syntax-doLast-doFirst-etc-td3337481.html是很好的例子很好的問題，顯示執行順序。

閱讀this article關於gradle生命週期，它會幫助你理解它。

[更新] 如果你想在publish執行階段運行任務aoeu可以調用publish.doFirstaoeu.execute。但據我所知，不應該這樣做。

task publish { 
} 

task aoeu << { 
    println "(2) during (run in execution phase as last statement)" 
} 

tasks.publish.doLast { 
    println "(3) after (run in execution phase as last statement)" 
} 

tasks.publish.doFirst { 
    println "(1) after (run in execution phase as FORST statement - before doLast/<<)" 
    aoeu.execute() 
} 

將返回

C:\>gradle publish 
:publish 
(1) after (run in execution phase as FORST statement - before doLast/<<) 
(2) during (run in execution phase as last statement) 
(3) after (run in execution phase as last statement) 

當我看到你想在publish任務的途中跑aoeu。我認爲最好的辦法做到這一點將是將publish任務分成兩個單獨的任務，並使用depends,mustRunAfter來控制執行順序。請看下面的例子：

task publishInit << { 
    println '(1)' 
} 

task aoeu << { 
    println '(2)' 
} 

task publish << { 
    println '(3)' 
} 

publish.dependsOn publishInit 
publish.dependsOn aoeu 
aoeu.mustRunAfter publishInit 

它將返回

C:\>gradle publish 
:publishInit 
(1) 
:aoeu 
(2) 
:publish 
(3)