Module executor 

Run a list of ExpandedNodes under a bounded-concurrency executor.

Semantics:

• Roots run concurrently under Semaphore(max_concurrent).
• Each root captures its written records (via a CapturingSink wrapper) so descendants can fan out per parent record.
• For each child whose parent has finished successfully, one pipeline invocation runs per parent record. ${parent.dotted.path} tokens in the source / sink config and state-key suffix are resolved against that record via interpolate_record.
• All invocations share one global semaphore — children and roots compete for the same budget.
• A node with depends_on: [row, …] starts only after every listed row’s invocations finish successfully — pure completion-ordering, no record hand-off. A failed or skipped dependency skips the node (and, in turn, its own subtree and dependents).
• on_error: continue (default) skips a failed node’s subtree but keeps running siblings. on_error: stop cancels everything after the first failure.
• State-key collisions among children of the same parent surface as a CliError::DuplicateStateKey.

Structs

ExecuteOptions

Knobs passed to run_expanded.

InvocationOutcome

One pipeline invocation’s outcome.

RunSummary

Aggregate outcome of run_expanded.

Functions

build_dlq_config

Translate a crate::config::DlqSpec from the YAML/JSON config into a runtime DlqConfig ready to attach to a Pipeline.

run_expanded

Execute every node in nodes. nodes must be in BFS order (roots first then children) — that’s what crate::expand::expand returns.