# Gradle copy creates an empty file

**URL:** <https://discuss.gradle.org/t/gradle-copy-creates-an-empty-file/18571>\
**Category:** Help/Discuss\
**Created:** [July 19, 2016, 5:24pm UTC](https://discuss.gradle.org/t/gradle-copy-creates-an-empty-file/18571 "2016-07-19T17:24:59Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![bostone](https://sea1.discourse-cdn.com/gradle/user_avatar/discuss.gradle.org/bostone/32/4785_2.png) [@bostone](https://discuss.gradle.org/u/bostone)\
**Post date:** [July 19, 2016, 5:24pm UTC](https://discuss.gradle.org/t/gradle-copy-creates-an-empty-file/18571/1 "2016-07-19T17:24:59Z")

</div>

I have a multi-project gradle build that copies some source files from the parent project into the build directory and then attempts to overwrite a token in one of the copied files. Everything runs OK but the file ends up being empty. Here’s the file snippet with the template to replace:

```
---
# file: clients.yaml
#properties shared by all client machines

jmeter_version: "${jmeterVersion}"

```

Here’s snippet of gradle.properties:

```
jmeterVersion=3.0

```

And here are two tasks that suppose to do the trick

```
/** This task copies files from pdo-shared */
task copyFromCommonProject(type:Copy, dependsOn: configurations.commonProjectContent){
    from configurations.commonProjectContent.collect{ zipTree(it) }
    into "$buildDir"
    /*doLast {
        updateAnsibleTokens.execute()
    }*/
}

task updateAnsibleTokens(type: Copy, dependsOn: copyFromCommonProject) {
   from "$buildDir/commons/ansible/group_vars/clients.yml"
   into "$buildDir/commons/ansible/group_vars/"
   expand(jmeterVersion: "$jmeterVersion")
}

```

I run this from the parent project as `gradle clean :tpcds-benchmark:updateAnsibleTokens`

First tasks copies all the files where and as expected it’s the 2nd task that does not work

Please notice commented out `doLast` section. I tried to run these two tasks as `gradle clean :tpcds-benchmark:copyFromCommonProject` by uncommenting `doLast` section and removing `dependsOn: copyFromCommonProject` from the 2nd task

In both instances client.yml ends up completely empty

P.S. Even if I disable expand(jmeterVersion: “$jmeterVersion”) line I will get an empty file. With some more tests it seems that copying a file on itself will generate an empty file so perhaps I’m just doing it wrong. The same code I have will work if I only change the destination directory

This is a [repost from Stackoverflow](http://stackoverflow.com/questions/38463095/gradle-copy-creates-an-empty-file)

---

<div class="post-metadata">

**Author:** ![bostone](https://sea1.discourse-cdn.com/gradle/user_avatar/discuss.gradle.org/bostone/32/4785_2.png) [@bostone](https://discuss.gradle.org/u/bostone)\
**Post date:** [July 19, 2016, 7:08pm UTC](https://discuss.gradle.org/t/gradle-copy-creates-an-empty-file/18571/2 "2016-07-19T19:08:27Z")

</div>

Basically I had to [reread this manual section](https://docs.gradle.org/current/userguide/build_lifecycle.html) to understand the lifecycle better.

Following my original example here’s 2 tasks that will work as intended. The problem as I started to suspect was that attempt to copy and modify `client.yml` was happening in the configuration cycle before the actual copying from the source was happening. Adding `<<` for the 2nd task ensured that the modification was happening in the execution cycle after the original file was copied

```
/** This task copies files from pdo-shared */
task copyFromCommonProject(type:Copy, dependsOn: configurations.commonProjectContent){
    from configurations.commonProjectContent.collect{ zipTree(it) }
    into "$buildDir"
}

task updateAnsibleTokens(type: Copy, dependsOn: copyFromCommonProject) << {
   from "$buildDir/commons/ansible/group_vars/clients.yml"
   into "$buildDir/commons/ansible/group_vars/"
   expand(jmeterVersion: "$jmeterVersion")
}

```