`copy_file`

Copy a regular file to a new location through the same tracked atomic writer as write_file. The copy runs on a tracked blocking worker and is bounded by IRONFLOW_MAX_FILE_BYTES (default 50 MiB).

Parameters

sourcestringrequired: Path to the source file. Must be a regular file. Supports ${ctx.key} interpolation.
destinationstringrequired: Path for the copied file. Missing parent directories are created. Supports ${ctx.key} interpolation.

Source and destination safety

The source follows the read_file policy: FIFOs, devices and directories are refused before any byte is read. Final-path symlinks are also refused on Unix and Windows. Its size is admitted against IRONFLOW_MAX_FILE_BYTES, and a source that changes size while being copied fails the copy.
Configured parent-directory aliases, including macOS /tmp, are resolved before staging. Unix pins the resolved directory, so retargeting the alias afterward cannot redirect the copy. This is not permission to follow a destination-file symlink.
A destination-file symlink, dangling link or special file is refused and its target is never opened or truncated. An existing regular destination is replaced only after a complete, flushed and synced copy.
On Unix, the copy keeps the source's permission bits (for example an executable 0751 script stays 0751); the staged file is created 0600 and receives the source mode before it is published. Other platforms use native file-permission semantics, not Unix modes; protect destination directories with appropriate access controls.
Source, admission, cancellation or commit failure leaves an existing destination unchanged and removes the staged file.
Portable platforms revalidate the destination immediately before an OS-level atomic replacement, but cannot close a hostile parent-directory swap race; protect destination trees from same-identity mutation.

Context Output

copy_file_source — The resolved source path (after interpolation).
copy_file_destination — The resolved destination path (after interpolation).
copy_file_success — true when the staged copy was committed.

Example

local flow = Flow.new("copy_demo")

flow:step("copy", nodes.copy_file({
    source = "/tmp/original.txt",
    destination = "/tmp/backup.txt"
}))

flow:step("done", nodes.log({
    message = "Copied to ${ctx.copy_file_destination}",
    level = "info"
})):depends_on("copy")

return flow