Add a processing stage to a parade flow

A stage defines a computational step in the flow with typed inputs and outputs, optional dependencies, and configurable data handling options.

Usage

stage(
  fl,
  id,
  f,
  needs = character(),
  schema,
  prefix = TRUE,
  sink = NULL,
  skip_when = NULL,
  hoist_struct = FALSE,
  inputs = NULL,
  input_artifacts = NULL,
  outputs = NULL,
  io_mode = c("off", "warn", "error"),
  retries = NULL,
  retry_backoff = NULL,
  retry_base = NULL,
  retry_on = NULL,
  resources = NULL,
  cpus = NULL,
  memory = NULL,
  time = NULL,
  ...
)

Arguments

fl: A parade_flow object
id: Unique stage identifier (character)
f: Function to execute for this stage
needs: Character vector of stage IDs this stage depends on
schema: Schema defining expected output structure (from returns())
prefix: Whether to prefix output columns with stage ID (logical)
sink: Optional sink specification for artifact persistence
skip_when: Optional function to determine when to skip this stage
hoist_struct: Whether to hoist nested data structures (logical)
inputs: Optional character vector of required input names for this stage.
input_artifacts: Optional character vector of inputs that must be artifact/file-reference values.
outputs: Optional character vector of declared output names. Defaults to schema column names.
io_mode: I/O contract behavior: "off" (default), "warn", or "error".
retries: Optional stage-level retry override (non-negative integer).
retry_backoff: Optional stage-level retry backoff override: "none", "fixed", "linear", "exponential".
retry_base: Optional stage-level retry base delay (seconds).
retry_on: Optional stage-level retry classifier override.
resources: Optional stage-level resource hints as a named list with keys cpus, memory, time (aliases: cpus_per_task, ncpus, mem).
cpus: Optional stage-level CPUs per task hint.
memory: Optional stage-level memory hint.
time: Optional stage-level walltime hint.
...: Additional constant arguments passed to the stage function

Value

The input flow with the new stage added

Examples

grid <- data.frame(x = 1:3)
fl <- flow(grid) |>
  stage("double", function(x) x * 2, schema = returns(result = dbl()))