Concourse task input folder is empty - concourse

Question

I'm experimenting with building a gradle based java app. My pipeline looks like this:
---
resources:
- name: hello-concourse-repo
type: git
source:
uri: https://github.com/ractive/hello-concourse.git
jobs:
- name: gradle-build
public: true
plan:
- get: hello-concourse-repo
trigger: true
- task: build
file: hello-concourse-repo/ci/build.yml
- task: find
file: hello-concourse-repo/ci/find.yml
The build.yml looks like:
---
platform: linux
image_resource:
type: docker-image
source:
repository: java
tag: openjdk-8
inputs:
- name: hello-concourse-repo
outputs:
- name: output
run:
path: hello-concourse-repo/ci/build.sh
caches:
- path: .gradle/
And the build.sh:
#!/bin/bash
export ROOT_FOLDER=$( pwd )
export GRADLE_USER_HOME="${ROOT_FOLDER}/.gradle"
export TERM=${TERM:-dumb}
cd hello-concourse-repo
./gradlew --no-daemon build
mkdir -p output
cp build/libs/*.jar output
cp src/main/docker/* output
ls -l output
And finally find.yml
---
platform: linux
image_resource:
type: docker-image
source: {repository: busybox}
inputs:
- name: output
run:
path: ls
args: ['-alR']
The output of ls at the end of the bash.sh script shows me that the output folder contains the expected files, but the find task only shows empty folders:
What am I doing wrong that the output folder that I'm using as an input in the find task is empty?
The complete example can be found here with the concourse files in the ci subfolder.

Answer 1

You need to remember some things:
There is an initial working directory for your tasks, lets call it '.' (Unless you specify 'dir'). In this initial directory you will find a directory for all your inputs and outputs.
i.e.
./hello-concourse-repo
./output
When you declare an output, there's no need to create a folder 'output' from your script, it will be created automatically.
If you navigate to a different folder in your script, you need to return to the initial working directory or use relative paths to find other folders.
Below you will find the updated script with some comments to fix the problem:
#!/bin/bash
export ROOT_FOLDER=$( pwd )
export GRADLE_USER_HOME="${ROOT_FOLDER}/.gradle"
export TERM=${TERM:-dumb}
cd hello-concourse-repo #You changed directory here, so your 'output' folder is in ../output
./gradlew --no-daemon build
# Add this line to return to the initial working directory or use ../output or $ROOT_FOLDER/output when compiling.
#mkdir -p output <- This line is not required, you already defined an output with this name
cp build/libs/*.jar ../output
cp src/main/docker/* ../output
ls -l ../output
Since you are defining ROOT_FOLDER variable you can use it to navigate.

Answer 2

You are still inside hello-concourse-repo and need to move output up one level.