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Part 3: YAML

This tutorial writes the factory from Part 1 and Part 2 as a YAML blueprint, and runs it with the ddes command. The file holds only configuration, and no Python is written.

1. Write the blueprint

Install the core package, which also installs the ddes command:

pip install dynamic-des

Create a file called first_factory.yaml:

docs/snippets/yaml/first_factory.yaml
# Part 3 of the tutorials: the first factory as a blueprint.
# Run it with: ddes run first_factory.yaml
simulation:
  sim_id: Factory_A
  factor: 1.0

egress:
  - type: Console

resources:
  lathe: {current_cap: 1, max_cap: 1}

services:
  # With no std, a normal distribution returns its mean every time.
  machining: {dist: normal, mean: 1.5}

arrivals:
  # One part every 2 seconds on average. Each arrival spawns one process_part.
  parts: {dist: exponential, rate: 0.5, spawn: process_part}

tasks:
  process_part:
    service: machining
    resource: lathe
    # The finished event's value. id_field adds the task id as part_id.
    payload: {}
    id_field: part_id

run:
  until: 10

Each section is one builder call from Part 2:

Section Part 2 Part 1
simulation SimulationContext(sim_id="Factory_A", factor=1.0) DynamicRealtimeEnvironment(factor=1.0) and the sim_id of SimParameter
egress .add_egress(ConsoleEgress()) env.setup_egress([ConsoleEgress()])
resources, services, arrivals .add_resource, .add_service, .add_arrival the SimParameter fields
spawn on the arrival the @app.arrival_loop function parts_generator
tasks the @app.task function process_part
run.until app.run(until=10.0) run(until=10.0)

payload is the value of the finished event. It is empty here, and id_field adds the task id to it as part_id, so the finished event is {'part_id': 0}, as in Part 2.

2. Run it

ddes run first_factory.yaml

The run prints the same records as Parts 1 and 2, and stops after 10 simulation seconds:

[TEL] {'sim_ts': 0.0, 'timestamp': '...', 'path_id': 'system.simulation.lag_seconds', 'value': 0.0}
[EVT] {'sim_ts': 1.596, 'timestamp': '...', 'key': 'task-0', 'value': {'path_id': 'Factory_A.service.machining', 'status': 'queued'}}
[EVT] {'sim_ts': 1.596, 'timestamp': '...', 'key': 'task-0', 'value': {'path_id': 'Factory_A.service.machining', 'status': 'started'}}
[EVT] {'sim_ts': 3.096, 'timestamp': '...', 'key': 'task-0', 'value': {'part_id': 0}}

--until overrides run.until, so ddes run first_factory.yaml --until 30 runs for 30 simulation seconds. A mistake in the file stops the load with the file and the line, before anything runs.

From Python, SimulationContext.from_yaml("first_factory.yaml") returns the same context that Part 2 builds, and run() runs it.

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