Input & output

This section explains the node resources that the algorithm container has access to.

File mounts

The algorithm has access to several file mounts:

Input

The input file contains the user defined input. The user specifies this when a task is created.

Output

The algorithm should write its output to this file. When the docker container exits the contents of this file will be send back to the vantage6-server.

Token

The token file contains a JWT token which can be used by the algorithm to communicate with the central server. The token can only be used to create a new task with the same image, and is only valid while the task has not yet been completed.

Temporary directory

The temporary directory can be used by an algorithm container to share files with other algorithm containers that:

• run on the same node

• have the same run_id

Algorithm containers that origin from another container (a.k.a master container or parent container) share the same run_id. i.o. if a user creates a task a new run_id is assigned.

The paths to these files and directories are stored in the environment variables, which we will explain now.

Environment variables

The environment variables contain the file paths to the file-mounts. The following environment variables are available:

Variable	Description
INPUT_FILE	path to the input file. The input file contains the user defined input for the algorithms.
OUTPUT_FILE	Path to the output file. The contents of the output file are send back to the vantage6-server when the algorithm container exits.
TOKEN_FILE	Path to the token file. The token file contains a JWT token which can be used to access the vantage6-server. This way the algorithm container is able to post new tasks and retrieve results.
TEMPORARY_FOLDER	Path to the temporary folder. This folder can be used to store intermediate results. These intermediate results are shared between all containers that have the same run_id. Algorithm containers which are created from an algorithm container themselves share the same run_id.
HOST	Contains the URL to the vantage6-server.
PORT	Contains the port to which the vantage6-server listens. Is used in combination with HOST and API_PATH.
API_PATH	Contains the api base path from the vantage6-server.
*_DATABASE_URI	Contains the URI of the local database. The * is replaced by the key specified in the node configuration file.

Additional environment variables can be specified in the node configuration file using the algorithm_env key. These additional variables are forwarded to all algorithm containers.