Checking models

verifyModel checks a BPMN model the way bpmn-server loads and runs it, without running it. Use it before saving a model, in a build, or in a test, to find what would otherwise fail only when an instance reaches it: a gateway with no way out, a script that does not compile, a timer that is not a valid duration, a service the application does not provide.

Available since bpmn-server 3.2.

From the command line

No server and no database are needed:

npx bpmn-server verify "Leave Application.bpmn"
npx bpmn-server verify processes/            # every .bpmn file in the folder
npx bpmn-server verify processes/ --json     # the results as JSON

processes/invoice.bpmn: 2 errors, 3 warnings
  error   script-syntax remind: The script does not compile: Unexpected token ')'
  error   timer-invalid wait: Timer duration '2 days' is not a valid ISO 8601 duration or cron expression.
  warning no-end-event invoice: Process has no end event.
  warning no-outgoing wait: Element has no outgoing sequence flow; the path ends here without an end event.
  warning no-diagram: The model has no diagram information (BPMN DI); the modeler can not display it.

Each line is the severity, the check's code, the element's id, and the message.

The exit code is 1 when a model has errors, so a build or CI step fails on a broken model.

From code

import { verifyModel } from 'bpmn-server';

const result = await verifyModel(xml, server);   // server is optional
if (!result.valid)
    for (const issue of result.issues.filter(i => i.severity == 'error'))
        console.log(issue.code, issue.elementId, issue.message);

With a server, the checks that need the application run too: whether the services a service task calls exist, whether a called process is a saved model, and whether a connector task's connector, operation and inputs are the server's.

Through the API, by model name or source:

const result = await api.model.verifyModel('Leave Application', user);

The result:

{
    valid: boolean,     // no errors (warnings do not make a model invalid)
    errors: number,
    warnings: number,
    issues: [{ severity: 'error' | 'warning' | 'info', code, message, elementId?, elementName?, processId? }]
}

code is stable: filter or suppress issues by it.

What is checked

Area	Codes
XML and references	empty-model, invalid-xml (error), unresolved-reference (error), duplicate-id (error), xml-warning
Processes	no-process (error), empty-process, no-start-event (error), no-end-event
Flows	flow-missing-endpoint (error), empty-condition (error), start-event-incoming, end-event-outgoing, unreachable, no-outgoing
Gateways	mixed-gateway, default-flow-not-outgoing (error), flow-without-condition, no-default-flow (info), event-gateway-target (error)
Diagram	no-diagram, not-in-diagram
The engine's load	engine-load-failed (error)
Scripts, conditions, expressions	script-syntax (error), expression-syntax (error), empty-script (info)
Timers	timer-not-defined (error), timer-invalid (error): ISO 8601 durations and dates, cron expressions
Services	service-not-named (info), service-not-found (info), unknown-app-service
Connectors (more)	connector-not-named (error), connector-and-service (error), connector-unknown (error), connector-unreadable (error), connector-operation-unknown (error), connector-input-missing (error), connector-disabled, connector-operation-disabled, connector-input-unknown
Decisions (more)	decision-not-named, decision-not-found, decision-invalid, decision-result-not-saved, decision-input-from-data (info)
Data objects	data-object-not-loaded, no-data-object-loader
Parameters and expressions	parameter-is-text, expression-juel, expression-unknown-name, template-not-closed
Called processes	call-activity-no-target (error), called-model-missing

Codes not marked are warnings.