In this tutorial I will show you how to execute task scripts and using task inputs to have the ability to pass data to concourse for processing.
For my other content on concourse, have a look at the concourse category.
Task Inputs
First, let's run a task on concourse that does not rely on any inputs.
platform: linux
image_resource:
type: docker-image
source: {repository: busybox}
run:
path: uname
args: ["-a"]
Running execute with the configuration from above:
$ fly -t ci e -c no_inputs.yml
executing build 37 at http://10.20.30.40/builds/37
initializing
running uname -a
Linux 2fd4e261-a708-4e15-4a4a-2bc50221a664 4.9.0-8-amd64 #1 SMP Debian 4.9.110-3+deb9u4 (2018-08-21) x86_64 GNU/Linux
succeeded
As you can see we have executed the command uname -a on one of the containers in Concourse.
Tasks Inputs: Specify Path
Now lets say, we have data that needs to be transferred to the container where we are running our tasks. For that we are using inputs.
In this example, we will set the input parameter in our task definition, and override the path with the cli. We will create a couple of files in a folder, then list them in the container where the task is running.
Creating the data:
$ mkdir my-data-folder
$ touch my-data-folder/test1.txt my-data-folder/test2.txt
Our task definition:
platform: linux
image_resource:
type: docker-image
source: {repository: busybox}
inputs:
- name: my-input
run:
path: ls
args: ['-alR']
As you can see our input name is called my-input and we will use the cli to map the local folder my-data-folder to the parameter name:
$ fly -t ci e -c inputs_required.yml -i my-input=./my-data-folder/
executing build 32 at http://10.20.30.40/builds/32
initializing
my-input: 262.13 KiB/s 0s
running ls -alR
.:
total 0
drwxr-xr-x 1 root root 16 Feb 10 08:53 .
drwxr-xr-x 1 root root 16 Feb 10 08:53 ..
drwxr-xr-x 1 root root 36 Feb 10 08:53 my-input
./my-input:
total 0
drwxr-xr-x 1 root root 36 Feb 10 08:53 .
drwxr-xr-x 1 root root 16 Feb 10 08:53 ..
-rw-r--r-- 1 501 staff 0 Feb 10 08:52 test1.txt
-rw-r--r-- 1 501 staff 0 Feb 10 08:52 test2.txt
succeeded
As you can see from the above output, the folder was uploaded and placed inside the container where we ran our task.
Task Inputs: Parent Directory
Then we can use parent directories. Running a task that relies on the input path which will be our current working directory. Note: the input name should be the same as the current working directory
The input name will be the only thing that differs, which will look like:
inputs:
- name: my-data-folder
Running the task:
$ cd my-data-folder
$ fly -t ci e -c ../input_parent_dir.yml
executing build 35 at http://10.20.30.40/builds/35
initializing
my-data-folder: 395.85 KiB/s 0s
running ls -alR
.:
total 0
drwxr-xr-x 1 root root 38 Feb 10 09:17 .
drwxr-xr-x 1 root root 16 Feb 10 09:17 ..
drwxr-xr-x 1 root root 18 Feb 10 09:17 my-data-folder
./my-data-folder:
total 0
drwxr-xr-x 1 root root 18 Feb 10 09:17 .
drwxr-xr-x 1 root root 38 Feb 10 09:17 ..
-rw-r--r-- 1 501 staff 0 Feb 10 09:15 test1.txt
-rw-r--r-- 1 501 staff 0 Feb 10 09:15 test2.txt
succeeded
The source code for this can be found at https://github.com/ruanbekker/concourse-tutorial/tree/master/02-task-inputs
Task Scripts:
In conjunction with inputs, we can let our task configuration reference a script that we want to execute, and using inputs, we can upload the current working directory to concourse, so then the container has context about the data that it needs.
Our task configuration task_show_hostname.yml
platform: linux
image_resource:
type: docker-image
source: {repository: busybox}
inputs:
- name: 03-task-scripts
run:
path: ./03-task-scripts/task_show_hostname.sh
Our executable script 03-task-scripts/task_show_hostname.sh
#!/bin/sh
get_hostname=$(hostname)
echo "Hostname is: ${get_hostname}"
Make sure to apply the executable permissions to the script:
$ chmod +x 03-task-scripts/task_show_hostname.sh
With this configuration, it uploads the current working directory to concourse, and the data inside the directory gets placed on the container's working directory: 03-task-scripts, which is the name of the input.
$ fly -t ci e -c 03-task-scripts/task_show_hostname.yml
executing build 39 at http://10.20.30.40/builds/39
initializing
03-task-scripts: 347.15 KiB/s 0s
running ./03-task-scripts/task_show_hostname.sh
Hostname is: 3ccb3c28-d452-4068-5ea1-101153803d93
succeeded
The source code for this example can be found at https://github.com/ruanbekker/concourse-tutorial/tree/master/03-task-scripts
That's it for Task Inputs and Task Scripts on Concourse, please feel free to have a look at my other content about Concourse
Thank You
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