# Google Cloud Platform

The Google Cloud Platform (GCP) engine allows you to run workflows on Google Cloud Platform using Cromwell. This engine is deployed using the DNAstack [engine installer](https://github.com/DNAstack/cromwell-on-gcp-workbench-engine-installer) following the Cromwell on GCP [installation instructions](https://docs.omics.ai/products/workbench/engines/adding-and-updating-an-engine/google-cloud-platform).

Since the underlying engine is Cromwell, you can use the same set of parameters that cromwell supports. Workbench's parameters are synonymous with Cromwell's parameters, and you can find the full list of Cromwell parameters in the [Cromwell documentation](https://cromwell.readthedocs.io/en/stable/wf_options/Overview/#workflow-options-overview).

The following is a list of parameters that are specific to the GCP engine specifically. For the complete list of options available in Workbench for a Cromwell engine see page on [Cromwell engine parameters](https://docs.omics.ai/products/workbench/engines/parameters/cromwell)

## Available Parameters

### `jes_gcs_root`=`STRING`

Where outputs of the workflow will be written. Expects this to be a GCS URL (e.g. gs\://my-bucket/workflows). If this is not set, this defaults to the value within `backend.jes.config.root` in the Configuration.

### `google_compute_service_account`=`STRING`

Alternate service account to use on the compute instance (e.g. <my-new-svcacct@my-google-project.iam.gserviceaccount.com>). If this is not set, this defaults to the value within `backend.jes.config.genomics.compute-service-account` in the Configuration if specified or default otherwise.

### `google_project`=`STRING`

Google project used to execute this workflow.

### `auth_bucket`=`STRING`

A GCS URL that only Cromwell can write to. The Cromwell account is determined by the `google.authScheme` (and the corresponding `google.userAuth` and `google.serviceAuth`). Defaults to the the value in `jes_gcs_root`.

### `monitoring_script`=`STRING`

Specifies a GCS URL to a script that will be invoked prior to the user command being run. For example, if the value for `monitoring_script` is "gs\://bucket/script.sh", it will be invoked as `./script.sh > monitoring.log &`. The value `monitoring.log` file will be automatically de-localized.

### `monitoring_image`=`STRING`

Specifies a Docker image to monitor the task. This image will run concurrently with the task container, and provides an alternative mechanism to `monitoring_script` (the latter runs inside the task container). For example, one can use `quay.io/broadinstitute/cromwell-monitor`, which reports cpu/memory/disk utilization metrics to Stackdriver.

### `monitoring_image_script`=`STRING`

Specifies a GCS URL to a script that will be invoked on the container running the `monitoring_image`. This script will be invoked instead of the `ENTRYPOINT` defined in the `monitoring_image`. Unlike the `monitoring_script` no files are automatically de-localized.

### `google_labels`=`OBJECT`

An object containing only string values. Represent custom labels to send with PAPI job requests. Per the PAPI specification, each key and value must conform to the regex `[a-z]([-a-z0-9]*[a-z0-9])?`.

### `enable_ssh_access`=`BOOLEAN`

If set to true, will enable SSH access to the Google Genomics worker machines. Please note that this is a community contribution and is not officially supported by the Cromwell development team.

### `delete_intermediate_output_files`=`BOOLEAN`

Experimental: Any File variables referenced in call output sections that are not found in the workflow output section will be considered an intermediate File. When the workflow finishes and this option is set to true, all intermediate File objects will be deleted from GCS. Cromwell must be run with the configuration value `system.delete-workflow-files` set to true. The default for both values is false. NOTE: The behavior of this option on other backends is unspecified.

### `enable_fuse`=`BOOLEAN`

Specifies if workflow tasks should be submitted to Google Pipelines with an additional `ENABLE_FUSE` flag. It causes container to be executed with `CAP_SYS_ADMIN`. Use it only for trusted containers. Please note that this is a community contribution and is not officially supported by the Cromwell development team.