Víðarr Administrator’s Guide

Running a Víðarr instance involves a few separate roles:

care and feeding of the Víðarr server (system operations)
care and feeding of the workflow runs (workflow operations)
creation and redesign of workflows (workflow development)

This guide is broken down by these roles, but they may overlap to some degree.

See Víðarr Code Style for preferred code formatting.

System Operations Guide

Running a Víðarr instance requires:

Java 17 or later
PostgreSQL 12 or later
Maven (for building, not required on installation machine)
Docker (for building, not required on installation machine)

Installing Víðarr on a Linux Instance

Build your own copy of Víðarr using Maven:

mvn install
mvn dependency:copy-dependencies

Pull all the JARs required for Víðarr and its plugins into a directory, say /srv/vidarr/jars:

mkdir -p /srv/vidarr/jars
cp vidarr-server/target/{,dependency}/*.jar /srv/vidarr/jars
# If you intend to use the command line interface
cp vidarr-cli/target/{,dependency}/*.jar /srv/vidarr/jars
# And any plugins you want to use
cp vidarr-cromwell/target/{,dependency}/*.jar /srv/vidarr/jars
cp vidarr-sh/target/{,dependency}/*.jar /srv/vidarr/jars

It can be easiest to launch Víðarr with a shellscript as follows stored in /srv/vidarr/run:

#!/bin/sh
exec /usr/lib/jvm/java-17-openjdk-amd64/bin/java -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:7000 --module-path $(ls /srv/vidarr/jars/*.jar|tr '\n' :) -m ca.on.oicr.gsi.vidarr.server/ca.on.oicr.gsi.vidarr.server.Main "$@"

To start Víðarr using systemd, create a vidarr.service as follows:

[Unit]
Description=Víðarr workflow provenance server

[Service]
User=debian
ExecStart=/srv/vidarr/run /srv/vidarr/config
KillMode=process
Restart=always
RestartSec=10

[Install]
WantedBy=multi-user.target

Create a new PostgreSQL database and role for Víðarr.

CREATE ROLE vidarr LOGIN PASSWORD 'mash keyboard here';
CREATE DATABASE vidarr OWNER vidarr;
\c vidarr;
ALTER SCHEMA public OWNER TO vidarr;
GRANT ALL ON SCHEMA public TO vidarr;

Now prepare the JSON configuration file /srv/vidarr/config as follows:

{
  "dbHost": "pg_db_host",
  "dbName": "pg_db_name",
  "dbPass": "pg_db_pass",
  "dbPort": 5432,
  "dbUser": "pg_db_user",
  "inputProvisioners": {},
  "name": "my_instance",
  "otherServers": {},
  "outputProvisioners": {},
  "port": 8088,
  "runtimeProvisioners": {},
  "targets": {},
  "url": "http://myinstance.vidarr.example.com/",
  "workflowEngines": {}
}

Replace all the pg_db_ values with the appropriate values to connect to the database.

"port" determines the port on which the Víðarr HTTP server will run. Choose something appropriate, especially if using a reverse proxy.

"url" should be set to the URL this Víðarr server is accessible on, after reverse proxying; Víðarr will use this to generate any self-referential URLs.

Víðarr also operates in a federated fashion so "name" should be set to a unique identifier for this server independent of its URL.

"otherServers" can be set up to connect to other Víðarr servers, using the other server’s "name" identifier as the key and the other server’s URL as the value.

Now, the plugins must be configured. Here are example configurations for using Cromwell in an HPC environment. Note that the names are arbitrary and multiple plugins can be defined with different names:

  "inputProvisioners": {
    "raw": {
      "formats": [
        "FILE",
        "DIRECTORY"
      ],
      "type": "raw"
    }
 },
  "outputProvisioners": {
    "cromwell-output": {
      "cromwellUrl": "http://cromwell-output.example.com:8000",
      "fileField": "provisionFileOut.inputFilePath",
      "fileSizeField": "provisionFileOut.fileSizeBytes",
      "checksumField": "provisionFileOut.fileChecksum",
      "checksumTypeField": "provisionFileOut.fileChecksumType",
      "outputPrefixField": "provisionFileOut.outputDirectory",
      "storagePathField": "provisionFileOut.fileOutputPath",
      "type": "cromwell",
      "wdlVersion": "1.0",
      "workflowOptions": {
        "read_from_cache": false,
        "write_to_cache": false
      },
      "workflowUrl": "http://example.com/provisionFileOut.wdl"
    }
  },
 "workflowEngines": {
    "local-cromwell": {
      "type": "cromwell",
      "url": "http://cromwell.example.com:8000"
    }
  }

Now, these different plugins can be linked together into a target. The target names will be visible to clients.

   "targets": {
    "local_hpc": {
      "inputProvisioners": [
        "raw"
      ],
      "outputProvisioners": [
        "cromwell-output"
      ],
      "consumableResources": [],
      "runtimeProvisioners": [],
      "workflowEngine": "local-cromwell"
    }
  },

Once configured, Víðarr should be able to start. On an empty database, it will automatically install its schema.

When new versions are released, simply replace the JARs and restart the service. It will automatically upgrade the database schema on start.

Creating a Development Environment

For workflow developers, it is also useful to install a /srv/vidarr/cli script:

#!/bin/sh
exec /usr/lib/jvm/java-17-openjdk-amd64/bin/java -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:7071 --module-path $(ls /srv/vidarr/jars/*.jar|tr '\n' :) -m ca.on.oicr.gsi.vidarr.cli/ca.on.oicr.gsi.vidarr.cli.Main "$@"

This file does not have to be on the Víðarr server and a copy of JARs and this script can be placed on another server. They will also need a configuration file to be able to run workflows in testing. It is a reduced form of the main configuration file:

{
  "engine": {
    "type": "cromwell",
    "url": "http://cromwell-dev.example.com:8000",
    "debugInflightRuns": false,
    "engineParameters": {
      "read_from_cache": "boolean",
      "write_to_cache": "boolean"
    }   
  },
  "inputs": [
    {
      "formats": [
        "DIRECTORY",
        "FILE"
      ],
      "type": "raw"
    }
  ],
  "outputs": [
    {
      "cromwellUrl": "http://cromwell-dev.example.com:8000",
      "chunks": [2, 4],
      "debugCalls": false,
      "fileField": "provisionFileOut.inputFilePath",
      "fileSizeField": "provisionFileOut.fileSizeBytes",
      "checksumField": "provisionFileOut.fileChecksum",
      "checksumTypeField": "provisionFileOut.fileChecksumType",
      "outputPrefixField": "provisionFileOut.outputDirectory",
      "storagePathField": "provisionFileOut.fileOutputPath",
      "type": "cromwell",
      "wdlVersion": "1.0",
      "workflowOptions": {
        "read_from_cache": false,
        "write_to_cache": false
      },
      "workflowUrl": "http://example.com/provisionFileOut.wdl"
    }
  ],
  "runtimes": []
}

For testing, only a single target can be configured, so the configuration for each plugin is not put though a layer of indirection. Otherwise, the plugin configuration are exactly as they would be for a normal server.

Workflow Operations

TODO – there is nothing useful at this point for workflow operations

Workflow development

Workflow developers need to test workflows, install those workflows in Víðarr, and make use of them via Shesmu.

Building Workflows

TODO – this is not implemented yet

Running Workflows Manually

The command line interface allows manually running workflows. See /srv/vidarr/cli run --help for details. Normally, the caller provides 3 pieces of information:

the arguments to the workflow
the external information to associate with the output of the workflow (metadata)
extra parameters to provide to the workflow engine

These are provided as either JSON files or JSON arguments on the command line. The exact format of these files will vary depending on the workflow and the plugin configuration.

After the workflow runs successfully, the provenance records generated by the workflow will be written out to a JSON file.

Testing Workflows

The command line interface allows for testing workflows. See /srv/vidarr/cli test --help for details. To run a series of automated tests, use test definition file. Many tests can be defined in one file.

[
  {
    "arguments": {},
    "description": "Basic test",
    "engineArguments": {},
    "id": "test1",
    "metadata": {},
    "validators": [
      {
        "metrics_calculate": "/srv/vidarr/test/calculate-md5",
        "metrics_compare": "/srv/vidarr/test/compare",
        "output_metrics": "/srv/vidarr/test/someworkflow/test1",
        "type": "script"
      }
    ]
  }
]

"arguments", "engineArguments", and "metadata" should be configured for each test to be run. Since each test is run individually, internal Víðarr IDs cannot be used for inputs as there will be no inputs. "id" is a unique identifier for the test and will be provided to plugins for generating provision out directories. "description" is a human-friendly name for the test to appear in logs.

After each test runs, the output will be validated. Currently, the only validator supported is "script", which runs a calculate script on the output files and then runs a comparison script that checks that the calculate script’s output matches the reference data.

Users have an option to provide a filepath to a directory where they would like the provisioned out file. For example, adding the argument: -o /scratch2/groups/gsi/development/ will provision the output file to the gsi scratch2 development directory.

If none is provided then the provisioned out file will be symlinked into a temporary directory. The "metrics_calculate" script will be run in that directory receiving the path to that directory as the first argument. Anything it writes to standard output will be captured. Then "metrics_calculate" will be called with the "output_metrics" as the first argument and the file generated in the previous step as the second argument. If it exits with a non-zero return code, then the test is allowed to pass.