Add examples of using jq for parsing JSON output

The CLI is able to output standard JSON for CLI commands. This makes it relatively easy to store infrastructure as code as well as to retrieve settings/status for Tower entities. jq is a great tool for this purpose. It allows you to retrieve specific entries within the JSON schema dumped by the CLI on the CLI.

For example if you use -o json for any command in the Tower CLI it will dump the output in JSON format. The command below is fetching various information about a run in the community/showcase workspace on Tower:

$ tw -o json runs view --id 5tMT2PJXCp1hz2 --workspace=community/showcase
{
  "general" : {
    "id" : "5tMT2PJXCp1hz2",
    "operationId" : "592f3c8f-c3d8-4055-9332-b3918d7XXXXX",
    "runName" : "silly_torvalds",
    "startingDate" : "2022-08-30T05:18:42Z",
    "commitId" : "959967364c7c0105b5b271acf0441fa9290e0d4c",
    "sessionId" : "f51221d8-dc76-4162-b47c-588ca03XXXXX",
    "username" : "brett-calcott",
    "workdir" : "s3://<MY_BUCKET>/scratch/5tMT2PJXCp1hz2",
    "container" : "",
    "executors" : "awsbatch",
    "computeEnv" : "AWS_Batch_Ireland",
    "nextflowVersion" : "22.06.1.edge",
    "status" : "SUCCEEDED"
  }
}

We can simply pipe this command to jq to get specific entries within the JSON output.

$ tw -o json runs view --id 5tMT2PJXCp1hz2 --workspace=community/showcase | jq -r '.[].status'
SUCCEEDED

Please consult the jq docs for more extensive patterns and usage.

seqeralabs / tower-cli

Add examples of using jq for parsing JSON output #251