dmstr/flowable-bundle

Reusable Symfony bundle that exposes a Flowable BPMN engine as Doctrine-less API Platform pass-through resources, a per-request HTTP client and matching flowable:* CLI commands.

The bundle owns no database tables: every resource reads from and writes to a remote Flowable REST engine at request time. Connection details (base URL and credentials) are resolved per request from an ApiConfiguration of type flowable (provided by dmstr/api-configuration-bundle).

Requirements

PHP >= 8.4
Symfony 7
API Platform 4, at least 4.3.18 (earlier releases do not enforce security on MCP tools)
A reachable Flowable REST engine (flowable-rest)
ext-pcntl — only for flowable:external-worker:run as a long-lived process, where it enables the graceful shutdown described under External worker tasks. Not a hard dependency: without it the command runs, it just cannot react to SIGTERM.

Installation

composer require dmstr/flowable-bundle

If you do not use a Symfony Flex recipe that registers the bundle, add it to config/bundles.php:

return [
    // ...
    Dmstr\Flowable\FlowableBundle::class => ['all' => true],
];

The bundle is self-wiring: it ships its own service definitions (FlowableBundle::loadExtension()), registers a dedicated flowable Monolog channel and needs no entry in the application's services.yaml. API Platform discovers the resource classes automatically from src/ApiResource.

Configuration

Create an ApiConfiguration of type flowable. Its configJson is validated against schema.json:

{
    "base_url": "http://flowable-rest:8080/flowable-rest/service",
    "auth_type": "basic",
    "username": "rest-admin",
    "password": "..."
}

auth_type is either basic (requires username + password) or bearer (requires token).

password and token are marked writeOnly in the schema, so dmstr/api-configuration-bundle (^0.5) stores them encrypted at rest and returns them masked as ******** on read; sending the mask back on update keeps the stored value. This requires a configured encryption key (CREDENTIALS_ENCRYPTION_KEY, see the api-configuration-bundle documentation). FlowableClientLocator decrypts them only to build the client; if decryption fails, the request fails with a SecretEncryptionException instead of sending the ciphertext to the engine.

Bundle configuration

The config root is dmstr_flowable. Its only options switch the bundle's MCP tools (see MCP tools); all default to false, so an application that does not opt in serves no Flowable tool:

# config/packages/dmstr_flowable.yaml
dmstr_flowable:
    mcp:
        read: true    # tools with readOnlyHint: true
        write: false  # every other tool
        deploy: false # the deploy tools, in addition to write

A tool whose annotations declare readOnlyHint: true is kept only when mcp.read is on; every other tool counts as writing and is kept only when mcp.write is on. The deploy tools flowable_deploy_bundle and flowable_dmn_deploy need mcp.deploy on top of mcp.write: a deployed BPMN or DMN definition is code the engine runs (script, shell and HTTP tasks, expressions), so an agent that can deploy and start processes can execute code on the engine. A switched-off tool is removed from API Platform's resource metadata, so it is neither listed nor callable. API Platform caches that metadata, so run bin/console cache:clear after changing a switch.

API resources

All resources are served under /api/flowable/*:

Resource	Notable operations
`FlowDeployment`	`GET /deployments`, `GET /deployments/{id}`, `POST /deployments/upload`, `DELETE`
`FlowProcessDefinition`	`GET /process_definitions`, `POST /process_definitions/{id}/start`, `GET /process_definitions/{id}/input_schema`
`FlowProcessInstance`	`GET /process_instances`, `POST /process_instances`, `DELETE`
`FlowTask`	`GET /tasks`, `POST /tasks/{id}/complete`, `GET /tasks/{id}/input_schema`
`FlowExecution`	`GET /executions`, `POST /executions/{id}/trigger`
`FlowHistoric*`	read-only history: activities, process instances, tasks, variables
`FlowDmnDeployment`	`GET /dmn_deployments`, `GET /dmn_deployments/{id}`, `POST /dmn_deployments/upload`, `DELETE`
`FlowDecision`	`GET /decisions`, `GET /decisions/{id}`, `POST /decisions/execute`
`FlowHistoricDecisionExecution`	read-only DMN evaluation history (audit, `failed` flag)
`FlowEventDeployment`	`GET /event_deployments`, `GET /event_deployments/{id}`, `POST /event_deployments/upload`, `DELETE`
`FlowEventDefinition`	read-only `GET /event_definitions`, `GET /event_definitions/{id}`
`FlowChannelDefinition`	read-only `GET /channel_definitions`, `GET /channel_definitions/{id}`
`FlowEventInstance`	`POST /event_instances` — send an event into the engine
`FlowExternalWorkerJob`	`GET /external_worker_jobs`, `POST /external_worker_jobs/acquire`, `POST /external_worker_jobs/{id}/{complete,fail,bpmnError,unacquire}`
`FlowJob`	read-only engine jobs: `GET /jobs?kind=async\|timer\|suspended\|deadletter\|history`, `GET /jobs/{id}/stacktrace`

External worker tasks

An <serviceTask flowable:type="external-worker" flowable:topic="…"> inverts the direction of an integration: the engine calls nothing, it puts a job on a topic and waits. That removes both problems a flowable:type="http" task has — no inbound route from the engine to the application, and no credential in the deployment artifact (the .bar usually lives in git; here the worker authenticates).

Write a handler and you are done — the interface is autoconfigured, so no attribute and no service entry is needed:

final class InvoiceHandler implements ExternalWorkerHandlerInterface
{
    public function topics(): array { return ['invoice-export']; }

    public function handle(ExternalWorkerJob $job): ExternalWorkerOutcome
    {
        $id = $job->variables['invoiceId'] ?? null;

        return ExternalWorkerOutcome::complete(['exportedAt' => date(DATE_ATOM)]);
        // or: ExternalWorkerOutcome::bpmnError('INVOICE_REJECTED')  → modelled error path
        // or: ExternalWorkerOutcome::fail(retries: 2)               → engine retry/backoff
        // throwing is reported as fail() with the exception message
    }
}

Run the poll loop with flowable:external-worker:run (see CLI below). Two rules the runner enforces, both deliberate: a handler that throws becomes a fail (the engine owns backoff and dead-lettering — the worker adds no second retry policy), and a topic without a handler is unacquired, never failed, because failing would spend a retry over an incomplete deployment.

lockDuration and retryTimeout are ISO-8601 durations (PT10M), not numbers. Note that a job which exhausted its retries disappears from GET /external_worker_jobs and is then only visible as GET /jobs?kind=deadletter — which is why the read-only FlowJob resource ships with this feature rather than after it.

DMN (decision) engine

flowable-rest ships the DMN engine in the same container under the /dmn-api prefix (the process engine lives under /service); both are reached through the same flowable ApiConfiguration. The DMN engine keeps a separate repository, so a .dmn packaged inside a process (.bar) deployment is not registered as a decision — deploy decision tables via POST /dmn_deployments/upload. POST /decisions/execute evaluates a decision by key ({ "decisionKey": "…", "inputVariables": {…}, "singleResult": false }) and returns the matching rule outputs on the response's result.

Engine version: the DMN resources require a Flowable engine >= 8.0.0 (the DMN repository resource is named decisions; earlier engines exposed decision-tables).

Event registry

flowable-rest ships a third engine repository under the /event-registry-api prefix, again behind the same flowable ApiConfiguration. It stores event definitions (.event — the payload contract and correlation keys of a business event) and channel definitions (.channel — how events travel: type is inbound/outbound, implementation the transport).

The operation worth having is POST /event_instances: it hands an event straight to an inbound channel inside the engine, with no message broker in between.

{
  "eventDefinitionKey": "myEvent",
  "channelDefinitionKey": "myInboundChannel",
  "eventPayload": { "customerId": "42", "amount": 19.99 }
}

Inbound event correlation (BPMN event sub-processes, receive events, boundary events) is therefore usable and verifiable without running Kafka or RabbitMQ. The outbound direction (engine → broker) leaves the engine and is a separate, broker-dependent concern that this bundle does not cover.

Both an event definition reference (eventDefinitionKey or eventDefinitionId) and a channel definition reference (channelDefinitionKey or channelDefinitionId) are required — the channel is what turns the payload into a correlated event. The engine answers 204 No Content, so the operation returns no body. eventPayload must be a JSON object.

No .bar/.zip bundles here. Unlike the process and DMN repositories, POST /event_deployments/upload accepts only a single .event or .channel file (the engine's own API description claims otherwise, but it only ever tests those two suffixes). A deployment needing several resources is uploaded one file at a time.

The input_schema endpoints return the per-task / per-definition input JSON-Schema, resolved at runtime from either an authored <formKey>.schema.json deployment resource or by converting inline Flowable form-data — via the pluggable flowable.task_form_source chain. Start forms work exactly like task forms: put flowable:formKey="<key>" on the BPMN startEvent and ship <key>.schema.json in the same deployment (.bar/ .zip); the resolved fields are wrapped in the businessKey / variables / apiConfiguration envelope of the start operation.

A start-form schema may carry a top-level x-businessKey object to customise the envelope's businessKey property — e.g. a Jedison x-watch/x-template pair that composes the key live from the form variables:

{
  "type": "object",
  "x-businessKey": {
    "title": "Business Key",
    "x-watch": { "jahr": "#/variables/jahr", "revierId": "#/variables/revierId" },
    "x-template": "foo-{{ jahr.value }}-{{ revierId.value }}"
  },
  "properties": { "…": {} }
}

The object is merged over the default businessKey definition and stripped from the variables schema — the composition rule ships with the process deployment instead of being hard-coded in a UI. Details (semantics, watch paths, Jedison rendering, IRI caveat): docs/start-form-business-key.md.

A task-form field may name the process variable holding its data with x-process-data-var, so a step that produced data can hand it to the next step's form:

{
  "landkreise": {
    "type": "array",
    "x-process-data-var": "landkreise"
  }
}

The variable's value — arrays and objects included, not just scalars like {{ token }} — is moved into the field's default, which form renderers use as the initial value; the keyword itself is stripped. Because completion writes the field back to that same variable, reopening an unfinished task shows the last saved state. A missing variable leaves the field without a default and keeps the keyword visible for debugging. Details: docs/task-form-prefill.md.

MCP tools

The bundle declares 14 MCP tools as API Platform McpTool entries on its resources. API Platform serves them when its MCP support is installed and enabled; the packages are suggested, not required:

symfony/mcp-bundle serves the tools;
mcp/sdk is the MCP server runtime it runs on.

Nothing is exposed until the switches dmstr_flowable.mcp.read / mcp.write / mcp.deploy are turned on. Every tool requires ROLE_FLOWABLE_ADMIN, the read tools included: unlike the HTTP read operations, they are not open to ROLE_USER, because tool results go to a language model and the engine has no per-user access check on tasks, variables and history.

Warning: tool results contain engine data that users or external systems wrote (variables, task descriptions, exception messages). Treat it as untrusted input to the model, and do not give an agent that reads such data the write or deploy tools without a human confirming each call.

Tool	Switch	Security	Tag (`_meta` `de.dmstr/tag`)	Backing operation
`flowable_list_process_definitions`	read	`ROLE_FLOWABLE_ADMIN`	`Flowable`	`GET /process_definitions` (`FlowProcessDefinitionProvider`)
`flowable_list_tasks`	read	`ROLE_FLOWABLE_ADMIN`	`Flowable`	`GET /tasks` (`FlowTaskProvider`)
`flowable_get_task_form`	read	`ROLE_FLOWABLE_ADMIN`	`Flowable`	like `GET /tasks/{id}/input_schema` (`FlowTaskFormProvider`)
`flowable_get_process_status`	read	`ROLE_FLOWABLE_ADMIN`	`Flowable`	composite: process instance, open tasks, executions (`FlowProcessStatusProvider`)
`flowable_history_get`	read	`ROLE_FLOWABLE_ADMIN`	`Flowable/History`	composite: historic activities, historic variables, failed decision executions (`FlowProcessHistoryProvider`)
`flowable_system_list_deadletter_jobs`	read	`ROLE_FLOWABLE_ADMIN`	`Flowable/System`	`GET /jobs?kind=deadletter`, kind fixed (`FlowJobProvider`)
`flowable_start_process`	write	`ROLE_FLOWABLE_ADMIN`	`Flowable`	`POST /process_instances`, by key or id (`ProcessInstanceCreateProcessor`)
`flowable_complete_task`	write	`ROLE_FLOWABLE_ADMIN`	`Flowable`	`POST /tasks/{id}/complete` (`TaskCompleteProcessor`)
`flowable_dmn_evaluate`	write	`ROLE_FLOWABLE_ADMIN`	`Flowable/DMN`	`POST /decisions/execute` (`DecisionExecuteProcessor`)
`flowable_events_send`	write	`ROLE_FLOWABLE_ADMIN`	`Flowable/Events`	`POST /event_instances` (`EventInstanceCreateProcessor`)
`flowable_system_trigger_execution`	write	`ROLE_FLOWABLE_ADMIN`	`Flowable/System`	`POST /executions/{id}/trigger` (`ExecutionTriggerProcessor`)
`flowable_dmn_deploy`	write + deploy	`ROLE_FLOWABLE_ADMIN`	`Flowable/DMN`	`POST /dmn_deployments/upload` with an inline file (`DmnDeploymentUploadProcessor`)
`flowable_deploy_bundle`	write + deploy	`ROLE_FLOWABLE_ADMIN`	`Flowable`	several inline files as one `.bar` deployment (`DeploymentBundleProcessor`)
`flowable_system_execute_timer_job`	write	`ROLE_FLOWABLE_ADMIN`	`Flowable/System`	no HTTP operation; `FlowableClientInterface::executeTimerJob()` (`TimerJobExecuteProcessor`)

Every tool carries annotations (readOnlyHint, destructiveHint, idempotentHint), its security expression and the de.dmstr/tag entry in _meta. Every tool that changes engine state in a way that cannot be undone (start, complete, trigger, send an event, deploy, execute a timer job) declares destructiveHint: true, so MCP clients ask before calling it; only flowable_dmn_evaluate, which adds no more than a history row, is a write tool with destructiveHint: false. Each description is one line that names the fields of the result, because some agent frameworks ignore structuredContent; the result is the serialised resource (or result object) in API Platform's MCP output format.

Notes on individual tools:

flowable_start_process starts by processDefinitionKey (latest version) or processDefinitionId, so an agent needs no prior lookup of the definition id; it is backed by POST /process_instances, not by POST /process_definitions/{id}/start.
flowable_dmn_evaluate changes no engine state except a history row, but it is gated behind ROLE_FLOWABLE_ADMIN like its HTTP operation, so it is declared a write tool (readOnlyHint: false, idempotentHint: true) and appears only with mcp.write.
flowable_get_process_status answers only for running instances; flowable_history_get covers ended ones. Both are composites: when one of their engine calls fails, the tool fails as a whole and never returns a partial result. Each list holds at most 200 rows; the *Total fields tell whether it was cut.
flowable_system_execute_timer_job moves the timer job to the executable jobs (POST management/timer-jobs/{id} with {"action": "move"}), where the async executor runs it at once. The remaining wait cannot be restored, hence destructiveHint: true.
flowable_deploy_bundle refuses .dmn files: a process deployment does not register decision tables in the DMN engine, so they go to flowable_dmn_deploy. Building the archive needs the PHP zip extension.

Tool arguments

All arguments are top-level. Operations with a JSON body take the body properties plus the URI variable (id), which is not part of the body; apiConfiguration selects the engine connection (full or partial UUID). List tools take page, itemsPerPage, sort, order and the filters of their HTTP collection; relation filters accept an id or an IRI. Variables are passed preferably as a map {"name": value}; the explicit list [{"name", "value", "type"}] is accepted too.

The advertised input schema of a tool is the operation input file next to its resource class (e.g. src/ApiResource/FlowTask/complete.input.json; tool-only files are named mcp<Verb>.input.json), with the URI variables added as required properties. Top-level allOf/anyOf alternatives ("one of these keys is required") are left out of the advertised schema because several MCP clients cannot represent them; the tool description names the rule, and the processor validates the full file.

Files are passed inline instead of as a multipart upload:

{
    "name": "rates.dmn",
    "content": "<?xml version=\"1.0\"?><definitions …>…</definitions>",
    "deploymentName": "rates"
}

name is the file name including its extension, content the file content as text; binary content (.bar, .zip) is sent base64-encoded with "contentEncoding": "base64". flowable_deploy_bundle takes a list of such files plus deploymentName:

{
    "deploymentName": "order-process",
    "files": [
        {"name": "order.bpmn20.xml", "content": "<?xml …"},
        {"name": "approve.schema.json", "content": "{\"type\": \"object\", …}"}
    ]
}

CLI

Every REST operation has a matching command; command IDs mirror the resource URLs:

flowable:health
flowable:deployments                 flowable:deployments:upload
flowable:process-definitions
flowable:process-instances           flowable:process-instances:create
flowable:tasks                       flowable:tasks:complete
flowable:executions                  flowable:executions:trigger
flowable:dmn:deployments             flowable:dmn:deployments:upload
flowable:dmn:decisions               flowable:dmn:rule:execute
flowable:events:deployments          flowable:events:deployments:upload
flowable:events:definitions          flowable:events:channels
flowable:events:instances:create
flowable:external-worker-jobs        flowable:external-worker:run
flowable:external-worker:complete    flowable:external-worker:fail
flowable:external-worker:bpmn-error  flowable:external-worker:unacquire
flowable:jobs

flowable:external-worker:run is the poll loop: --topic (repeatable, empty = every registered handler's topics), --worker-id, --lock-duration=PT10M, --batch, --max-jobs, --time-limit, --once.

Graceful shutdown requires ext-pcntl. With pcntl loaded, SIGTERM / SIGINT finish the current job, unacquire whatever is still locked and exit, so a container restart leaves no jobs locked. Without pcntl the command still runs (getSubscribedSignals() returns an empty list, so Symfony does not refuse to start it) — but nothing handles the signal: on SIGTERM the acquired jobs stay locked until their lockDuration expires, and the engine hands them out again only after that. Install pcntl before running this as a long-lived worker process, and keep --lock-duration short enough that a lost lock is not painful. Verified 2026-07-29 on a php:8.4 image without pcntl.

Security

Reading is open to any authenticated user. Starting, triggering and completing (all write operations) require ROLE_FLOWABLE_ADMIN. The MCP tools all require ROLE_FLOWABLE_ADMIN, see MCP tools. The acting user is taken from the authenticated identity (JWT sub) and propagated to Flowable — see docs/tenant-and-user.md.

Documentation

docs/walkthrough-vacation-request.md — end-to-end walkthrough of a human-task process.
docs/tenant-and-user.md — tenant and acting-user model.
docs/start-form-business-key.md — the x-businessKey start-form extension.
docs/task-form-prefill.md — the x-process-data-var task-form extension.

Tests

The PHPUnit suite (tests/, configuration phpunit.dist.xml) runs without an engine, a database or a kernel: the Flowable client is a test double, and the MCP tool metadata is read from the resource attributes with API Platform's attribute metadata factory.

composer install
vendor/bin/phpunit

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dmstr/flowable-bundle

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Name		Name	Last commit message	Last commit date
config		config
docs		docs
src		src
tests		tests
.gitignore		.gitignore
CHANGELOG.md		CHANGELOG.md
CLAUDE.md		CLAUDE.md
LICENSE		LICENSE
README.md		README.md
composer.json		composer.json
phpunit.dist.xml		phpunit.dist.xml
schema.json		schema.json

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dmstr/flowable-bundle

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Event registry

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