[kalwei]

What

fsmes scenario — a player that writes timed tag values into any OPC UA server, Kepware first, so a product can be run through a line and every system reading that server (this MES, another MES, a script under test) sees the same thing.

• fsmes scenario play <file> --endpoint ... [--security --user --password] [--speed] [--from mm:ss] — writes each value at its time, as the node's own type, and prints a line per write. Ctrl-C stops.
• fsmes scenario check <file> [--endpoint ...] [--timeline] — offline, names the line of each mistake in the file; connected, reports every tag's type, access and the driver rule, writing nothing.
• fsmes scenario serve <file> — a rehearsal server holding the file's tags as writable memory tags at their own addresses, so the whole thing can be tried without Kepware.

The file is JSON (PyYAML is not a dependency of the product): tags as short names for node ids or browse paths, drivers, steps with value or ramp, and product — stations in order, advance_s apart, each bumping a count from what it holds, setting a state, an id, or other tags.

The safety rule, in code

Before anything is written, every target is read. A tag whose channel is not declared Simulator or Memory Based in the file is refused, with the channel and the reason; so is a declared Advanced Simulator or PLC driver. Kepware's address space does not name a channel's driver (its System Tags page lists none), so the declaration is required — and on a Kepware server the player also looks for _System._ComId, _System._NetworkAdapter and an IP-address _DeviceId, any of which refuses the channel whatever the file says. A read-only tag is reported, not written. Nothing is written unless every target passes. There is no override flag.

Shadow mode refuses it. MES_SHADOW=true promises this MES changes nothing outside its own database; a scenario changes tags on another server, so play refuses before it connects and again at the write. Both new paths are in fsmes.shadow.REGISTER (now 38 entries: opc.scenario_play refused, sim.scenario_rehearsal allowed), and the register's source scan now matches .write_attribute(, which it did not see before.

Writes carry no source timestamp (Kepware refuses those) and use the node's own variant type (Kepware answers a wrong one with BadTypeMismatch).

How verified

• tests/test_scenario_player.py, 19 tests (one: play in shadow mode writes nothing and never connects), plus a proof in tests/test_shadow_mode.py: the file's mistakes named by line (bad time, unknown tag, unknown key, invalid JSON, a duplicated key); ramp and product expansion; the driver rule; type coercion with ranges and array lengths; and against in-test asyncua servers (slow tier): string, bool, Int16, UInt32, Int16[4] and Float written as their own types at the right times at 2x; a PLC-driver channel refused with nothing at all written; a Kepware-shaped server whose device is addressed by IP overruling a "Simulator" declaration; read-only and missing tags reported; the lab's product walk played into its own rehearsal server.
• By hand, on loopback port 4945: setpoint-drill.json checked and played into fsmes run-opc-sim --replay (its setpoints are the tags it lets a client write); product-through-the-line.json played into fsmes scenario serve and read back with fsmes opc-browse.
• Not verified here: a real KEPServerEX. Whether a Simulator channel shows none of the three device signs is what Scott's first check --endpoint against his server will say.
• ruff check . and pytest green locally, except test_the_calibration_the_supervisor_records_is_on_the_gauges_own_register, which fails on this machine in the evening when the local date and the UTC date differ; it does not touch this change.

Docs: docs/operate/scenarios.md (in the nav), with the Kepware notes from Kepware's Simulator Driver Help and System Tags page, and which points remain to check on a real server.

🤖 Generated with Claude Code

[github-actions]

Thanks for the first pull request. Checks: every commit signed off (git commit -s), ruff and pytest green, and the house-rules checklist in the template. The maintainer reviews within a few days.