4. Your first sequence

Open a second terminal — the first one is busy serving your step — and set it up:

$ cd ~/anvil-book
$ export PATH="$PWD/anvil-v0.5.0-x86_64-linux-musl:$PATH"
$ mkdir sequences

The file

Create sequences/first.yseq:

name: first

executors:
  - { name: bench, type: grpc, host: 127.0.0.1, port: 9201 }

main:
  - name: board/measure_rail
    executor: bench
    limit: { type: range, min: 4.75, max: 5.25 }

It is YAML. Line by line:

• name names the sequence in reports.
• executors is the list of executors this sequence talks to. Each has a name you choose, a type — grpc for a process listening on a port, as your C# executor is — and where to find it.
• main is the list of steps to run. Chapter 6 adds setup and cleanup.
• Each step has the name the executor publishes and the executor that serves it, by the name you gave it above.
• limit is the acceptance criterion: a range passes when the measurement is between min and max.

Always write executor: on a step. A step without one is sent to a small executor built into the engine for its own demonstrations, which does not know your steps.

The extension can be .yseq or .yaml; Anvil reads both the same way.

Run it

$ anvil sequences/first.yseq
ejecutor de pasos escuchando en 40243
secuencia 'first' cargada (1 pasos en main, 0 subsecuencia(s) externa(s), 1 ejecutor(es))
motor conectado
conectado a los ejecutores de pasos (embebido en 127.0.0.1:40243)
catálogo pedido
1 paso(s) comprobados contra el catálogo de su ejecutor
=== first: pass ===
  [pass] board/measure_rail: 
conexión cerrada; esperando otra
$ echo $?
0

Two kinds of lines are mixed there.

The report is the part between === first: pass === and the step lines under it: the sequence passed, and so did its one step. It goes to standard output.

Everything else is diagnostics on the error stream: the engine starting its built-in executor on a free port, loading the file, connecting, and — the line that matters — 1 paso(s) comprobados contra el catálogo de su ejecutor, “1 step checked against its executor’s catalog”. Before running anything, Anvil asked bench what it serves and checked that the sequence only asks for steps that exist. These messages are still in Spanish in 0.5.0 (#59).

The exit code is 0 because the sequence passed. Anything else — a fail, an error, a file that does not load — exits with 1.

To see only the report, send the diagnostics away:

$ anvil sequences/first.yseq 2>/dev/null
=== first: pass ===
  [pass] board/measure_rail: 

The rest of the book does that, unless the diagnostics are the point.

The console report does not show the measured value — 4.98 appears nowhere. The reports in chapter 10 carry it.

When a name is wrong

Make a typo on purpose. sequences/unknown.yseq asks for measure_rial:

name: unknown

executors:
  - { name: bench, type: grpc, host: 127.0.0.1, port: 9201 }

main:
  - name: board/measure_rial
    executor: bench

$ anvil sequences/unknown.yseq 2>&1 | tail -n 3
la secuencia no casa con lo que ofrecen los ejecutores (1 problema(s)):
  - step 'board/measure_rial': executor 'bench' does not serve it (it serves: board/measure_rail)
conexión cerrada; esperando otra

“The sequence does not match what the executors offer”: bench does not serve board/measure_rial, and the message lists what it does serve. Nothing ran. This check happens on every run, before the first step, so a misspelt step never gets as far as the bench.