Fan-out (for_each glob)

The for_each field lets you spawn one process instance per glob match. This is useful when the number of configuration files (or similar inputs) is not known at authoring time.

YAML syntax

Add a for_each block to a process definition with two required sub-fields:

nodes:
  for_each:
    glob: "/etc/nodes/*.yaml"
    as: CONFIG_PATH
  run: node-agent --config $CONFIG_PATH
  once: true

Variable substitution

For each glob match the as variable is:

1. Set in the instance’s environment so the child process can read it directly.
2. Substituted into the run string — both $VAR and ${VAR} forms are replaced with the matched path before the command is executed.

Instance naming

Glob results are sorted lexicographically. Each instance is named {template_name}-{index} where the index is 0-based. For the example above, three matches would produce processes named nodes-0, nodes-1, and nodes-2.

Group completion

A process_exited dependency can reference the template name (e.g. nodes). The dependency is satisfied only when all instances have exited successfully (exit code 0). This lets you gate a downstream process on the entire fan-out group completing:

nodes:
  for_each:
    glob: "/etc/nodes/*.yaml"
    as: CONFIG_PATH
  run: provision --config $CONFIG_PATH
  once: true

deploy:
  depends:
    - process_exited: nodes
  run: deploy-cluster
  once: true

Here deploy will not start until every nodes-* instance has completed successfully.

Constraints

• Zero matches is an error. If the glob pattern matches no files, procman exits with an error rather than silently doing nothing.
• once: true is typical. Fan-out processes usually represent one-shot tasks (provisioning, migration, etc.). Without once: true, any instance exiting would trigger shutdown of the entire process group.