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Task Inputs

In the previous section the only inputs to the task container were the image used. Base images, such as Docker images, are relatively static and relatively big, slow things to create. So Concourse supports inputs into tasks to pass in files/folders for processing.

Consider the working directory of a task that explicitly has no inputs:

cd ../task-inputs
fly -t tutorial e -c no_inputs.yml

The task runs ls -al to show the (empty) contents of the working folder inside the container:

running ls -al
total 8
drwxr-xr-x    2 root     root          4096 Feb 27 07:23 .
drwxr-xr-x    3 root     root          4096 Feb 27 07:23 ..

Note that above we used the short-hand form of the execute command in this example, simply e, as the action. Many commands have shortened single character forms, for example fly s is an alias for fly sync.

In the example task inputs_required.yml we add a single input:

- name: some-important-input

When we try to execute the task:

fly -t tutorial e -c inputs_required.yml

It will fail:

error: missing required input `some-important-input`

Commonly if wanting to run fly execute we will want to pass in the local folder (.). Use -i name=path option to configure each of the required inputs:

fly -t tutorial e -c inputs_required.yml -i some-important-input=.

Now the fly execute command will upload the . directory as an input to the container. It will be made available at the path some-important-input:

running ls -alR
total 12
drwxr-xr-x    3 root     root          4096 Dec 18 02:35 .
drwxr-xr-x    3 root     root          4096 Dec 18 02:35 ..
drwxr-xr-x    1 root     root          4096 Dec 18 02:35 some-important-input

total 24
drwxr-xr-x    1 root     root          4096 Dec 18 02:35 .
drwxr-xr-x    3 root     root          4096 Dec 18 02:35 ..
-rw-r--r--    1 501      20             156 Dec  9 22:26 input_parent_dir.yml
-rw-r--r--    1 501      20             162 Dec  9 22:26 inputs_required.yml
-rw-r--r--    1 501      20             123 Dec  9 22:26 no_inputs.yml
-rwxr-xr-x    1 501      20             522 Dec 17 21:31

To pass in a different directory as an input, provide its absolute or relative path:

fly -t tutorial e -c inputs_required.yml -i some-important-input=../task-hello-world

The fly execute -i option can be removed if the current directory is the same name as the required input.

The task input_parent_dir.yml contains an input task-inputs which is also the current directory. So the following command will work and return the same results as above:

fly -t tutorial e -c input_parent_dir.yml