# Instruction file¶

An instruction file is a YAML document. It has three top-level elements; apt, source, data, run, result, and upload.

## apt¶

The apt section specifies a package list to be installed via apt.

apt:
- nodejs
- package_a
- package_b


## souce¶

The source section specifics how to obtain source codes. It could have either git repository URL or normal URL. A git repository URL is a URL ends with .git. Such URLs will be used with git clone. If you want to use ssh to connect your repository, you may need to deploy valid ssh keys in /root/.ssh in this container. For normal URL, in addition to the basic scheme http and https, this url supports gs which means an object in Google Cloud Storage, and dropbox. See the next section for detail.

### Example¶

Clone source code from a git repository:

source: https://github.com/itslab-kyushu/youtube-comment-scraper.git


source: https://exmaple.com/abc.txt


source: gs://your_bucket/path_to_object


source: dropbox://www.dropbox.com/sh/abcdefg/ABCDEFGHIJKLMN


## data¶

The data section specifies URLs to be downloaded. It must be a list of extended URLs and the format of extended URL is scheme://hostname/path or scheme://hostname/path:dest URL schemes Roadie-GCP supports are gs, dropbox and schemes which curl supports. To download objects, Roadie-GCP uses curl but uses gsutil for gs scheme. dropbox is a pseudo scheme to download objects from Dropbox. To use this scheme, get public URL from Dropbox and then replace https to dropbox. When you download objects via Dropbox’s public link, they are zipped. Using dropbox scheme will unzip those objects.

Downloaded objects will be put in /data which is the default working directory. You can also use the second format of URL to specify destinations of objects.

## run¶

The run section specifies what commands will be run. It must be a list of commands. Those commands will be executed via shell. STDOUT of those commands will be stored to files named stdout*.txt and uploaded to Google Cloud Storage. For example, the outputs of the first commands will be stored to stdout0.txt. On the other hands, STRERR will be outputted to docker logs.

## result¶

The result section specifies where outputted results should be stored. Outputted results include STDOUT of each commands. Roadie-GCP supports only a place in Google Cloud Storage, currently. Thus, the value of the result element must be a URL of which scheme is gs.

The upload section specifies other files to be uploaded as results. This section consist of a list of glob patterns. Objects matching to one of the patterns will be uploaded to the cloud storage. Each glob pattern can have a destination after :. For example, "*.out:result means objects matching *.out will be uploaded to result folder.