V10 Import an ODCS contract

Use your current course session. Preparation and course runner · R script ↓

Optional deep dive. Enable only the options named in each block, after preparing its packages or services.

V10a Export an ODCS contract

Goal: Save a portable contract.

Prerequisites: H04; adapters, yaml; extras or gui.

The resulting ODCS document is also used in the YAML editor exercises.

training_step(
  "V10a",
  {
    odcs_path <- file.path(training_root, "policies.contract.yaml")
    if (!file.exists(odcs_path)) {
      dataraft.adapters::dr_contract_odcs(policy_contract, path = odcs_path)
    }
    cat(
      readLines(odcs_path),
      sep = "
  "
    )
  },
  needs = c("H04"),
  packages = c("dataraft.adapters", "yaml"),
  enabled = training_options$extras || training_options$gui,
  optional = TRUE
)

Expected result: Readable YAML with contract metadata and columns.

Task: Why use the suffix .contract.yaml?

V10 Import an ODCS contract

Goal: Execute the supported subset.

Prerequisites: V10a.

Unknown executable rules are not evaluated as arbitrary R. Unsupported constructs must be rejected explicitly.

training_step(
  "V10",
  {
    imported_contract <- dataraft.adapters::dr_contract_from_odcs(odcs_path)
    odcs_product <- dr_product(
      "policies.odcs",
      policies,
      contract = imported_contract
    )
    print(dr_run(odcs_product, write = FALSE))
  },
  needs = c("V10a"),
  enabled = training_options$extras || training_options$gui,
  optional = TRUE
)

Expected result: The saved contract is used for our data.

Task: Can dr_contract_yaml replace this roundtrip?