FlowX Engine setup

Infrastructure prerequisites

Before installing the FlowX.AI Engine, verify that the following infrastructure components are installed and configured:

Kafka
Elasticsearch
PostgreSQL or Oracle
MongoDB

Dependencies

The FlowX Engine requires the following components:

Database: Primary storage for the engine (PostgreSQL or Oracle)
Redis Server: Used for caching. See Redis Configuration
Kafka: Handles messaging and event-driven architecture. See Configuring Kafka

For a microservices architecture, services typically manage their data via dedicated databases.

Required external services

Redis Cluster: Caches process definitions, compiled scripts, and Kafka responses
Kafka Cluster: Enables communication with external plugins and integrations

Configuration setup

FlowX.AI Engine uses environment variables for configuration. This section covers key configuration areas:

Database configuration
Authorization & access roles
Kafka configuration
File upload size
Elasticsearch connection

Database configuration

The FlowX Engine supports both PostgreSQL and Oracle as its primary relational database.

PostgreSQL

Environment variable	Description
`SPRING_DATASOURCE_URL`	Database URL for PostgreSQL
`SPRING_DATASOURCE_USERNAME`	Username for PostgreSQL
`SPRING_DATASOURCE_PASSWORD`	Password for PostgreSQL
`SPRING_DATASOURCE_DRIVERCLASSNAME`	Driver class for PostgreSQL

Oracle

Environment variable	Description
`SPRING_DATASOURCE_URL`	Database URL for Oracle
`SPRING_DATASOURCE_USERNAME`	Username for Oracle
`SPRING_DATASOURCE_PASSWORD`	Password for Oracle
`SPRING_DATASOURCE_DRIVERCLASSNAME`	Driver class for Oracle

Default: oracle.jdbc.OracleDriver

MongoDB configuration

Configure connection to the Runtime MongoDB instance:

Environment variable	Description	Default value
`SPRING_DATA_MONGODB_RUNTIME_URI`	URI for connecting to MongoDB	Format: `mongodb://${RUNTIME_DB_USERNAME}:${DB_PASSWORD}@<host1>,<host2>,<arbiter-host>:<port>/${DB_NAME}?retryWrites=false`
`RUNTIME_DB_USERNAME`	MongoDB username	`app-runtime`
`DB_NAME`	MongoDB database name	`app-runtime`

Configuration parameters

There are two types of Config Params that can be read from the environment: variables and secrets. There is one provider for variables and secrets extracted from the environment variables, and two providers for the ones extracted from Kubernetes. By default, the variables and secrets are extracted from environment variables (env provider).

Configuration parameters from environment variables (default)

The env provider used for variables and secrets extracts them from environment variables. For security reasons, the env provider uses an allow list regex which defaults to FLOWX_CONFIGPARAM_.*. This means only environment variables that match this naming pattern can be read at runtime into configuration params (either as variables or secrets). Feel free to edit it to match the environment variables that you use in your deployment.

Environment variable	Description	Default value
`FLOWX_CONFIGPARAMS_VARS_PROVIDER`	Provider type for variables	`env`
`FLOWX_CONFIGPARAMS_VARS_ALLOWLISTREGEX`	Regular expression to match allowed env variables for variables	`FLOWX_CONFIGPARAM_.*`
`FLOWX_CONFIGPARAMS_SECRETS_PROVIDER`	Provider type for secrets	`env`
`FLOWX_CONFIGPARAMS_SECRETS_ALLOWLISTREGEX`	Regular expression to match allowed env variables for secrets	`FLOWX_CONFIGPARAM_.*`

Configuration parameters from Kubernetes Secrets and ConfigMaps

Use the following configuration to read Config Params from Kubernetes Secrets and ConfigMaps:

Environment variable	Description	Values
`FLOWX_CONFIGPARAMS_VARS_PROVIDER`	Provider type for variables	`k8s-configmaps`
`FLOWX_CONFIGPARAMS_SECRETS_PROVIDER`	Provider type for secrets	`k8s-secrets`

These providers can be configured as follows:

Environment variable	Description	Values
`FLOWX_CONFIGPARAMS_PROVIDERS_K8SCONFIGMAPS_CONFIGMAPSLIST_0_`	Name of the ConfigMap to use for variables	`flowx-configparams`
`FLOWX_CONFIGPARAMS_PROVIDERS_K8SSECRETS_SECRETSLIST_0_`	Name of the Secret to use for secrets	`flowx-configparams`

You can configure multiple secrets and ConfigMaps by incrementing the index number (e.g., FLOWX_CONFIGPARAMS_PROVIDERS_K8SSECRETS_SECRETSLIST_1, FLOWX_CONFIGPARAMS_PROVIDERS_K8SCONFIGMAPS_CONFIGMAPSLIST_1). Values are overridden based on the order in which the maps are defined.The default provider is env, but there is a built-in allowlist with the regex pattern FLOWX_CONFIGPARAM_.*. This means only configuration parameters that match this naming pattern can be read at runtime, whether they are environment variables or secret variables.

Config params cache

Configure caching behavior for configuration parameters to optimize performance:

Environment variable	Description	Default value
`FLOWX_CACHE_CONFIGPARAMS_TTLSECONDS`	Time-to-live in seconds for cached configuration params	`120`
`FLOWX_CACHE_CONFIGPARAMS_MAXENTRIES`	Maximum number of entries in the config params cache	`500`

These settings control how long configuration parameters are cached in memory before being refreshed from the source (environment variables, ConfigMaps, or Secrets). Adjust these values based on how frequently your configuration changes and your memory constraints.

Authorization & access roles

This section covers OAuth2 configuration settings for securing the Spring application.

Security configuration

Environment variable	Description	Default value
`SECURITY_TYPE`	Type of security mechanism	`oauth2`
`SECURITY_BASIC_ENABLED`	Enable basic authentication	`false`
`SECURITY_PUBLIC_PATHS_0`	Public path not requiring authentication	`/api/platform/components-versions`
`SECURITY_PUBLIC_PATHS_1`	Public path not requiring authentication	`/manage/actuator/health`
`SECURITY_PATH_AUTHORIZATIONS_0_PATH`	Security path pattern	`"/api/**"`
`SECURITY_PATH_AUTHORIZATIONS_0_ROLES_ALLOWED`	Roles allowed for path access	`"ANY_AUTHENTICATED_USER"`

Resource server (opaque-token introspection)

Environment variable	Description	Default value
`SECURITY_OAUTH2_BASE_SERVER_URL`	OAuth2 server base URL
`SECURITY_OAUTH2_REALM`	OAuth2 realm name
`SECURITY_OAUTH2_CLIENT_CLIENT_ID`	Client ID for token introspection
`SECURITY_OAUTH2_CLIENT_CLIENT_SECRET`	Client secret for token introspection

Service account configuration

Environment variable	Description	Default value
`SECURITY_OAUTH2_SERVICE_ACCOUNT_ADMIN_CLIENT_ID`	Service account client ID	`flowx-process-engine-sa`
`SECURITY_OAUTH2_SERVICE_ACCOUNT_ADMIN_CLIENT_SECRET`	Service account client secret
`SPRING_SECURITY_OAUTH2_CLIENT_PROVIDER_MAINAUTHPROVIDER_TOKEN_URI`	Provider token URI	`${SECURITY_OAUTH2_BASE_SERVER_URL}/realms/${SECURITY_OAUTH2_REALM}/protocol/openid-connect/token`

For more information about the necessary service account, see Process Engine Service Account.

Configuring Kafka

Kafka handles all communication between the FlowX.AI Engine, external plugins, and integrations. It also notifies running process instances when certain events occur.

Kafka connection settings

Environment variable	Description	Default value
`KAFKA_BOOTSTRAP_SERVERS`	Kafka bootstrap servers (fallback: `SPRING_KAFKA_BOOTSTRAP_SERVERS`)	`localhost:9092`
`KAFKA_SECURITY_PROTOCOL`	Security protocol for Kafka (fallback: `SPRING_KAFKA_SECURITY_PROTOCOL`)	`PLAINTEXT`

Message routing configuration

Environment variable	Description	Default value
`KAFKA_DEFAULT_FX_CONTEXT`	Default context value for message routing when no context is provided	`""` (empty string)

When KAFKA_DEFAULT_FX_CONTEXT is set and an event is received on Kafka without an fxContext header, the system will automatically apply the default context value to the message.

Kafka consumer retry settings

Environment variable	Description	Default value
`KAFKA_AUTHEXCEPTIONRETRYINTERVAL`	Interval between retries after `AuthorizationException` (seconds)	`10`

Consumer groups & consumer threads configuration

Both a producer and a consumer must be configured:

Configuring a Kafka Producer

Configuring a Kafka Consumer

FlowX Engine Kafka communication pattern

About consumer groups and threads

A consumer group is a set of consumers that jointly consume messages from one or more Kafka topics. Each consumer group has a unique identifier (group ID) that Kafka uses to manage message distribution. Thread numbers refer to the number of threads a consumer application uses to process messages. Increasing thread count can improve parallelism and efficiency, especially with high message volumes.

Consumer group configuration

Environment variable	Description	Default value
`KAFKA_CONSUMER_GROUPID_NOTIFYADVANCE`	Group ID for notifying advance actions	`advance`
`KAFKA_CONSUMER_GROUPID_NOTIFYPARENT`	Group ID for notifying when a subprocess is blocked	`notify-parent`
`KAFKA_CONSUMER_GROUPID_ADAPTERS`	Group ID for messages related to adapters	`adapters`
`KAFKA_CONSUMER_GROUPID_SCHEDULERRUNACTION`	Group ID for running scheduled actions	`scheduler-run-action`
`KAFKA_CONSUMER_GROUPID_SCHEDULERADVANCING`	Group ID for messages indicating continuing advancement	`scheduler-advancing`
`KAFKA_CONSUMER_GROUPID_MESSAGEEVENTS`	Group ID for message events	`message-events`
`KAFKA_CONSUMER_GROUPID_PROCESS_START`	Group ID for starting processes	`process-start`
`KAFKA_CONSUMER_GROUPID_PROCESS_STARTFOREVENT`	Group ID for starting processes for an event	`process-start-for-event`
`KAFKA_CONSUMER_GROUPID_PROCESS_EXPIRE`	Group ID for expiring processes	`process-expire`
`KAFKA_CONSUMER_GROUPID_PROCESS_OPERATIONS`	Group ID for processing operations from Task Management plugin	`process-operations`
`KAFKA_CONSUMER_GROUPID_PROCESS_BATCHPROCESSING`	Group ID for processing bulk operations from Task Management plugin	`process-batch-processing`
`KAFKA_CONSUMER_GROUPID_PROCESS_UIFLOWUPDATE`	Group ID for processing UI flow session variable updates	`ui-flow-update`

Consumer thread configuration

Environment variable	Description	Default value
`KAFKA_CONSUMER_THREADS_NOTIFYADVANCE`	Number of threads for notifying advance actions	`6`
`KAFKA_CONSUMER_THREADS_NOTIFYPARENT`	Number of threads for notifying when a subprocess is blocked	`6`
`KAFKA_CONSUMER_THREADS_ADAPTERS`	Number of threads for processing messages related to adapters	`6`
`KAFKA_CONSUMER_THREADS_SCHEDULERADVANCING`	Number of threads for continuing advancement	`6`
`KAFKA_CONSUMER_THREADS_SCHEDULERRUNACTION`	Number of threads for running scheduled actions	`6`
`KAFKA_CONSUMER_THREADS_MESSAGEEVENTS`	Number of threads for message events	`6`
`KAFKA_CONSUMER_THREADS_PROCESS_START`	Number of threads for starting processes	`6`
`KAFKA_CONSUMER_THREADS_PROCESS_STARTFOREVENT`	Number of threads for starting processes for an event	`2`
`KAFKA_CONSUMER_THREADS_PROCESS_EXPIRE`	Number of threads for expiring processes	`6`
`KAFKA_CONSUMER_THREADS_PROCESS_OPERATIONS`	Number of threads for processing operations from task management	`6`
`KAFKA_CONSUMER_THREADS_PROCESS_BATCHPROCESSING`	Number of threads for processing bulk operations from task management	`6`
`KAFKA_CONSUMER_THREADS_PROCESS_UIFLOWUPDATE`	Number of threads for processing UI flow session variable updates	`6`

All events that start with a configured pattern will be consumed by the Engine. This enables you to create new integrations and connect them to the engine without changing the configuration.

Configuring Kafka topics

Topic naming configuration

Environment Variable	Description	Default Value
`KAFKA_TOPIC_NAMING_PACKAGE`	Package prefix for topic names	`ai.flowx.`
`KAFKA_TOPIC_NAMING_ENVIRONMENT`	Environment segment for topic names
`KAFKA_TOPIC_NAMING_VERSION`	Version suffix for topic names	`.v1`
`KAFKA_TOPIC_NAMING_SEPARATOR`	Primary separator for topic names	`.`
`KAFKA_TOPIC_NAMING_SEPARATOR2`	Secondary separator for topic names	`-`
`KAFKA_TOPIC_NAMING_ENGINERECEIVEPATTERN`	Engine receive pattern	`engine.receive.`
`KAFKA_TOPIC_NAMING_INTEGRATIONRECEIVEPATTERN`	Integration receive pattern	`integration.receive.`

Core engine topics

Environment variable	Description	Default value
`KAFKA_TOPIC_PROCESS_NOTIFY_ADVANCE`	Topic used internally for advancing processes	`ai.flowx.core.notify.advance.process.v1`
`KAFKA_TOPIC_PROCESS_NOTIFY_PARENT`	Topic used for sub-processes to notify the parent process	`ai.flowx.core.notify.parent.process.v1`
`KAFKA_TOPIC_PATTERN`	Pattern the Engine listens on for incoming events	`ai.flowx.engine.receive.*`
`KAFKA_TOPIC_PROCESS_EVENT_MESSAGE`	Topic for process message events	`ai.flowx.core.message.event.process.v1`

Topics related to the Task Management plugin

Environment variable	Description	Default value
`KAFKA_TOPIC_TASK_OUT`	Topic used for sending notifications to the plugin	`ai.flowx.plugin.tasks.trigger.save.task.v1`
`KAFKA_TOPIC_PROCESS_OPERATIONS_IN`	Topic for receiving information about operations performed	`ai.flowx.core.trigger.operation.v1`
`KAFKA_TOPIC_PROCESS_OPERATIONS_BULKIN`	Topic where operations can be performed in bulk	`ai.flowx.core.trigger.operations.bulk.v1`

Topics related to the Notification plugin

Environment variable	Description	Default value
`KAFKA_NOTIFICATION_OUT`	Topic for sending notification requests to the Notification plugin	`ai.flowx.plugin.notification.trigger.send.notification.v1`

The KAFKA_NOTIFICATION_OUT topic must resolve to the same value as KAFKA_TOPIC_NOTIFICATION_INTERNAL_IN in the Notification plugin configuration.

Topics related to the Document plugin

The process-engine receives results from document-plugin operations on topics matching the pattern ai.flowx.engine.receive.plugin.document.*. The following topics are used for file encryption and decryption operations:

Topic name	Description
`ai.flowx.engine.receive.plugin.document.encrypt.file.results.v1`	Topic for receiving file encryption results from document-plugin
`ai.flowx.engine.receive.plugin.document.decrypt.file.results.v1`	Topic for receiving file decryption results from document-plugin

These topics are automatically matched by the Engine’s KAFKA_TOPIC_PATTERN configuration (default: ai.flowx.engine.receive.*). No additional configuration is required. The topics must be created in your Kafka infrastructure before deployment.

OPERATIONS_IN request example

{
  "operationType": "UNASSIGN", //type of operation performed in Task Management plugin
  "taskId": "some task id",
  "processInstanceUuid": "1cff0b7d-966b-4b35-9e9b-63b1d6757ec6",
  "swimlaneName": "Default",
  "swimlaneId": "51ec1241-fe06-4576-9c84-31598c05c527",
  "owner": {
    "firstName": null,
    "lastName": null,
    "username": "service-account-flowx-process-engine-account",
    "enabled": false
  },
  "author": "admin@flowx.ai"
}

BULK_IN request example

{
  "operations": [
    {
      "operationType": "HOLD",
      "taskId": "some task id",
      "processInstanceUuid": "d3aabfd8-d041-4c62-892f-22d17923b223", // the id of the process instance
      "swimlaneName": "Default", //name of the swimlane
      "owner": null,
      "author": "john.doe@flowx.ai"
    },
    {
      "operationType": "HOLD",
      "taskId": "some task id",
      "processInstanceUuid": "d3aabfd8-d041-4c62-892f-22d17923b223",
      "swimlaneName": "Default", //name of the swimlane
      "owner": null,
      "author": "john.doe@flowx.ai"
    }
  ]
}      

To send additional keys in the response, attach them in the header. For example, you can use a requestID key.

A response should be sent on a callbackTopic if it is mentioned in the headers:

Callback topic with requestID header example

{"processInstanceId": ${processInstanceId}, "callbackTopic": "test.operations.out", "requestID":"1234567890"}

Task manager operations include: assignment, unassignment, hold, unhold, terminate. These are matched with the ...operations.out topic on the engine side. For more information, see the Task Management plugin documentation:📄 Task management plugin

Topics related to UI flow session updates

Environment variable	Description	Default value
`KAFKA_TOPIC_UIFLOW_UPDATE_IN`	Topic for receiving UI flow session variable updates	`ai.flowx.core.trigger.ui-flow.update.v1`

Topics related to the scheduler extension

Environment variable	Description	Default value
`KAFKA_TOPIC_PROCESS_EXPIRE_IN`	Topic for requests to expire processes	`ai.flowx.core.trigger.expire.process.v1`
`KAFKA_TOPIC_PROCESS_SCHEDULE_OUT_SET`	Topic used for scheduling process expiration	`ai.flowx.core.trigger.set.schedule.v1`
`KAFKA_TOPIC_PROCESS_SCHEDULE_OUT_STOP`	Topic used for stopping process expiration	`ai.flowx.core.trigger.stop.schedule.v1`
`KAFKA_TOPIC_PROCESS_SCHEDULE_IN_RUN_ACTION`	Topic for requests to run scheduled actions	`ai.flowx.core.trigger.run.action.v1`
`KAFKA_TOPIC_PROCESS_SCHEDULE_IN_ADVANCE`	Topic for events related to advancing through a database	`ai.flowx.core.trigger.advance.process.v1`

Topics related to Timer Events

Environment variable	Description	Default value
`KAFKA_TOPIC_PROCESS_SCHEDULEDTIMEREVENTS_OUT_SET`	Used to communicate with Scheduler microservice	`ai.flowx.core.trigger.set.timer-event-schedule.v1`
`KAFKA_TOPIC_PROCESS_SCHEDULEDTIMEREVENTS_OUT_STOP`	Used to communicate with Scheduler microservice	`ai.flowx.core.trigger.stop.timer-event-schedule.v1`

Topics related to the Search Data service

Environment variable	Description	Default value
`KAFKA_TOPIC_DATA_SEARCH_IN`	Topic that the Engine listens on for search requests	`ai.flowx.core.trigger.search.data.v1`
`KAFKA_TOPIC_DATA_SEARCH_OUT`	Topic used by the Engine to reply after finding a process	`ai.flowx.engine.receive.core.search.data.results.v1`

Topics related to the Audit service

Environment variable	Description	Default value
`KAFKA_TOPIC_AUDIT_OUT`	Topic for sending audit logs	`ai.flowx.core.trigger.save.audit.v1`

Topics related to Elasticsearch indexing

Environment variable	Default value
`KAFKA_TOPIC_PROCESS_INDEX_OUT`	`ai.flowx.core.index.process.v1`

Processes that can be started by sending messages to a Kafka topic

Environment variable	Description	Default value
`KAFKA_TOPIC_PROCESS_START_IN`	Topic for requests to start a new process instance	`ai.flowx.core.trigger.start.process.v1`
`KAFKA_TOPIC_PROCESS_START_OUT`	Topic for sending the reply after starting a new process instance	`ai.flowx.core.confirm.start.process.v1`

Topics related to Message Events

Environment variable	Default value
`KAFKA_TOPIC_PROCESS_STARTFOREVENT`	`ai.flowx.core.trigger.start-for-event.process.v1`

Topics related to Events-gateway microservice

Environment variable	Description	Default value
`KAFKA_TOPIC_EVENTSGATEWAY_OUT_MESSAGE`	Outgoing messages from process-engine to events-gateway	`ai.flowx.eventsgateway.engine.commands.message.v1`
`KAFKA_TOPIC_EVENTSGATEWAY_OUT_DISCONNECT`	Disconnect commands from process-engine to events-gateway	`ai.flowx.eventsgateway.engine.commands.disconnect.v1`
`KAFKA_TOPIC_EVENTSGATEWAY_OUT_CONNECT`	Connect commands from process-engine to events-gateway	`ai.flowx.eventsgateway.engine.commands.connect.v1`

Topics related to platform components

Environment variable	Description	Default value
`KAFKA_TOPIC_PLATFORM_COMPONENTS_VERSIONS_OUT`	Topic for platform version caching	`ai.flowx.core.trigger.platform.versions.caching.v1`

Inter-service topic coordination

When configuring FlowX services, ensure the following:

The Engine’s pattern must match the pattern used by services sending messages to the Engine
The integrationPattern must match the pattern used by the Integration Designer
Output topics from one service must match the expected input topics of another service

For example:

Services send to topics matching ai.flowx.engine.receive.* → Engine listens
Engine sends to topics matching ai.flowx.integration.receive.* → Integration Designer listens

Kafka message size configuration

Environment variable	Description	Default value
`KAFKA_MESSAGE_MAX_BYTES`	Maximum message size in bytes	`52428800` (50MB)

This setting affects:

Producer message max bytes
Producer max request size
Consumer max partition fetch bytes

Kafka authentication (when using SASL_PLAINTEXT)

For secure environments, enable OAuth authentication with the following environment variables:

Environment Variable	Description	Default Value
`KAFKA_OAUTH_CLIENT_ID`	OAuth client ID	`kafka`
`KAFKA_OAUTH_CLIENT_SECRET`	OAuth client secret	`kafka-secret`
`KAFKA_OAUTH_TOKEN_ENDPOINT_URI`	OAuth token endpoint	`kafka.auth.localhost`

When using the kafka-auth profile, the security protocol will automatically be set to SASL_PLAINTEXT and the SASL mechanism will be set to OAUTHBEARER.

Configuring Elasticsearch connection

The Process Engine uses Elasticsearch for process instance indexing and search capabilities. Configure the connection using these environment variables:

Variable	Description	Default Value
`SPRING_ELASTICSEARCH_REST_PROTOCOL`	Connection protocol	`https`
`SPRING_ELASTICSEARCH_REST_URIS`	URL(s) of Elasticsearch nodes (no protocol)	-
`SPRING_ELASTICSEARCH_REST_DISABLESSL`	Disable SSL verification	`false`
`SPRING_ELASTICSEARCH_REST_USERNAME`	Authentication username	-
`SPRING_ELASTICSEARCH_REST_PASSWORD`	Authentication password	-

For indexing setup, check the Configuring Elasticsearch indexing section.

Indexing settings

Variable	Description	Default Value
`FLOWX_INDEXING_ENABLED`	Enable/disable indexing globally	`true`
`FLOWX_INDEXING_TYPE`	Indexing strategy (http, kafka, no-indexing)	`http`
`FLOWX_ELASTICSEARCH_INDEXSETTINGS_NAME`	Name of the Elasticsearch index	`process_instance`
`FLOWX_ELASTICSEARCH_INDEXSETTINGS_SHARDS`	Number of primary shards	`2`
`FLOWX_ELASTICSEARCH_INDEXSETTINGS_REPLICAS`	Number of replica shards	`0`
`FLOWX_INDEXING_OPTIMISTICLOCKINGRETRIES`	Retry attempts for optimistic locking (HTTP only)	`3`

Configuring file upload size

Environment variable	Description	Default value
`SPRING_SERVLET_MULTIPART_MAXFILESIZE`	Maximum file size allowed for uploads	`50MB`
`SPRING_SERVLET_MULTIPART_MAXREQUESTSIZE`	Maximum request size allowed for uploads	`50MB`

Connecting the Advancing controller

To use the advancing controller, configure the following variables:

Environment variable	Description	Default value
`ADVANCING_DATASOURCE_URL`	Connection URL for Advancing Postgres DB	`jdbc:postgresql://postgresql:5432/advancing`
`ADVANCING_DATASOURCE_USERNAME`	Username for Advancing DB connection	`flowx`
`ADVANCING_DATASOURCE_PASSWORD`	Password for Advancing DB connection	`-`
`ADVANCING_DATASOURCE_MAXIMUMPOOLSIZE`	Maximum size of the advancing datasource connection pool. Worker threads open their own connections, configured separately via `ADVANCING_PICKINGTHREADS` and `ADVANCING_PROCESSINGTHREADS`	`20`

Configuring the Advancing controller

Environment variable	Description	Default value
`ADVANCING_TYPE`	Type of advancing mechanism	`PARALLEL` (alternatives: `KAFKA`, `PARALLEL`)
`ADVANCING_PICKINGTHREADS`	Number of worker threads for reading from database (picking operations)	`1`
`ADVANCING_PROCESSINGTHREADS`	Number of threads for parallel processing of advancing events	`20`
`ADVANCING_PROCESSINGBUFFERSIZE`	Maximum buffer size for processing queue. Controls how many events can be queued	`20`
`ADVANCING_BLOCKPICKINGIFNOWORKERAVAILABLE`	Block picking operations when no worker threads are available	`true`
`ADVANCING_PICKINGPAUSEMILLIS`	Pause duration between picking batches (ms)	`50`
`ADVANCING_COOLDOWNAFTERSECONDS`	Cooldown period after processing a batch (seconds)	`120`
`ADVANCING_SCHEDULER_HEARTBEAT_CRONEXPRESSION`	Cron expression for the heartbeat	`"/2 * * * ?"`

How the new advancing controller works:

Picking threads (ADVANCING_PICKINGTHREADS): Controls how many worker threads read events from the database. This handles only the picking/reading operations.
Processing buffer (ADVANCING_PROCESSINGBUFFERSIZE): Acts as a queue between picking and processing. When the buffer is full, no new events are read. When there’s available space (even just 1 position), that amount of events will be read.
Processing threads (ADVANCING_PROCESSINGTHREADS): Controls how many threads process the advancing events in parallel. Events are processed instantly if processing threads are available. If all processing threads are busy, events accumulate in the buffer until it reaches capacity.
Blocking behavior (ADVANCING_BLOCKPICKINGIFNOWORKERAVAILABLE): When enabled, prevents picking operations if no worker threads are available, ensuring better resource management.

Advancing controller setup

CAS lib configuration

Environment Variable	Description	Default Value
`FLOWX_SPICEDB_HOST`	SpiceDB server hostname	`spicedb`
`FLOWX_SPICEDB_PORT`	SpiceDB server port	`50051`
`FLOWX_SPICEDB_TOKEN`	SpiceDB authentication token	-

Configuring cleanup mechanism

Environment variable	Description	Default value
`SCHEDULER_THREADS`	Number of threads for the scheduler	`10`
`SCHEDULER_PROCESSCLEANUP_ENABLED`	Activates the cron job for process cleanup	`false`
`SCHEDULER_PROCESSCLEANUP_CRONEXPRESSION`	Cron expression for the process cleanup scheduler	`0 /5 0-5 * ?` (every 5 minutes between 12 AM and 5 AM)
`SCHEDULER_PROCESSCLEANUP_BATCHSIZE`	Number of processes to clean up in one batch	`1000`
`SCHEDULER_MASTERELECTION_CRONEXPRESSION`	Cron expression for the master election process	`30 /3 * * ?` (every 3 minutes)

Managing subprocesses expiration

Environment variable	Description	Default value
`FLOWX_PROCESS_EXPIRESUBPROCESSES`	When true, terminates all subprocesses upon parent process expiration. When false, subprocesses follow their individual expiration settings	`true`

Configuring application management

The following configuration from versions before 4.1 will be deprecated in version 5.0:

MANAGEMENT_METRICS_EXPORT_PROMETHEUS_ENABLED: Enables or disables Prometheus metrics export.

Starting from version 4.1, use the following configuration instead. This setup is backwards compatible until version 5.0.

Environment variable	Description	Default value
`MANAGEMENT_PROMETHEUS_METRICS_EXPORT_ENABLED`	Enables Prometheus metrics export	`false`

RBAC configuration

Process Engine requires specific RBAC permissions for proper access to Kubernetes resources:

rbac:
  create: true
  rules:
    - apiGroups:
        - ""
      resources:
        - secrets
        - configmaps
        - pods
      verbs:
        - get
        - list
        - watch

Ingress and CORS

The Process Engine is exposed on both the admin and public hosts, with a dedicated route for runtime process instances on the admin host. Routing is configured through the FlowX Helm chart, which renders either a Kubernetes Ingress (default) or a Gateway API HTTPRoute per service. CORS handling lives in the service code; only the allowed-origins list is deployment-specific.

Service routes

Host group	External path	Backend receives	Notes
admin	`/onboarding/api`	`/api/...`	Strip `/onboarding`
public	`/onboarding/api`	`/api/...`	Strip `/onboarding`
admin-instances	`/api/instances`	`/api/instances/...`	Path preserved

Paths are set through services.process-engine.ingress.<key>.path (or gateway.<key>.paths) in the chart values. The admin and public routes share the same backend route family — the /onboarding prefix is stripped before forwarding so the backend receives /api/....

CORS configuration

Environment Variable	Description	Default Value
`APPLICATION_CORS_ALLOW_ORIGIN`	Comma-separated list of origins allowed to call this service from the browser. Supports wildcard subdomains. Must include every Designer, runtime renderer, and integration domain that calls Process Engine.	`-`

Allowed methods, allowed headers (including Authorization, Content-Type, Fx-Workspace-Id), and credential handling are baked into the service’s application.yaml with safe defaults. Override these only if you have a non-standard requirement. For the complete route reference, Gateway API HTTPRoute configuration, and route customization, see the ingress configuration guide.

For SSE (Server-Sent Events) communication configuration, refer to the Events Gateway setup guide.

Script engine configuration

The process engine uses a native script engine for executing JavaScript and Python business rules. The native engine runs scripts in separate Node.js and Python worker processes.

Environment variable	Description	Default value
`APPLICATION_SCRIPT_ENGINE_PROVIDER`	Script engine provider (`native` or `graalvm`)	`native`
`APPLICATION_SCRIPT_ENGINE_NATIVEENGINE_JS_POOLSIZE`	Number of Node.js worker processes	`16`
`APPLICATION_SCRIPT_ENGINE_NATIVEENGINE_JS_EXECUTIONTIMEOUTMS`	Execution timeout per script (ms)	`5000`
`APPLICATION_SCRIPT_ENGINE_NATIVEENGINE_JS_MAXEXECUTIONSPERWORKER`	Max executions before a worker is recycled	`10000`
`APPLICATION_SCRIPT_ENGINE_NATIVEENGINE_JS_MAXPAYLOADSIZEBYTES`	Max input payload size (bytes)	`1048576` (1 MB)
`APPLICATION_SCRIPT_ENGINE_NATIVEENGINE_PYTHON_POOLSIZE`	Number of Python worker processes	`8`
`APPLICATION_SCRIPT_ENGINE_NATIVEENGINE_PYTHON_EXECUTIONTIMEOUTMS`	Execution timeout per script (ms)	`10000`
`APPLICATION_SCRIPT_ENGINE_NATIVEENGINE_PYTHON_MAXEXECUTIONSPERWORKER`	Max executions before a worker is recycled	`10000`
`APPLICATION_SCRIPT_ENGINE_NATIVEENGINE_PYTHON_MAXPAYLOADSIZEBYTES`	Max input payload size (bytes)	`1048576` (1 MB)

The native script engine is the default starting with 5.9.0, replacing the previous GraalVM-based engine. Scripts run in isolated subprocess pools. To revert to GraalVM, set APPLICATION_SCRIPT_ENGINE_PROVIDER=graalvm.

Stuck token recovery

Automatically recovers process tokens that get stuck due to transient failures.

Environment variable	Description	Default value
`SCHEDULER_STUCKTOKENRECOVERY_ENABLED`	Turn on or off stuck token recovery	`false`
`SCHEDULER_STUCKTOKENRECOVERY_CRONEXPRESSION`	Cron expression for recovery sweeps	`0 /5 * * ?`
`SCHEDULER_STUCKTOKENRECOVERY_THRESHOLDMINUTES`	Minutes a token must be stuck before recovery triggers	`10`
`SCHEDULER_STUCKTOKENRECOVERY_BATCHSIZE`	Max tokens recovered per sweep	`100`
`SCHEDULER_STUCKTOKENRECOVERY_MAXAGEHOURS`	Max age (hours) of stuck tokens to consider	`4`

Troubleshooting

Common issues

Engine fails to start

Symptoms: The process-engine pod crashes or restarts repeatedly during startup.Solutions:

Verify PostgreSQL connectivity and that the database exists and is accessible
Check Redis connection settings (SPRING_REDIS_HOST, SPRING_REDIS_PORT) and ensure Redis is running
Confirm Kafka bootstrap servers are reachable (SPRING_KAFKA_BOOTSTRAPSERVERS)
Review pod logs for specific connection errors — the first failing dependency is usually the root cause
Ensure all required secrets (database passwords, OAuth credentials) are correctly mounted

Process instances not advancing

Symptoms: Processes get stuck at certain nodes and do not move forward.Solutions:

Verify the advancing controller is running and properly connected (ADVANCING_DATASOURCE_JDBC_URL)
Check that advancing-related Kafka topics exist and are correctly configured (KAFKA_TOPIC_PROCESS_NOTIFY_ADVANCE)
Review the advancing controller type (ADVANCING_TYPE) and thread configuration
Ensure the scheduler extension topics are properly set up for timer-based advances
Check Kafka consumer group lag for advance and scheduler-advancing groups

Elasticsearch indexing not working

Symptoms: Process instances are not appearing in search results or the indexing service reports errors.Solutions:

Confirm FLOWX_INDEXING_ENABLED is set to true
Verify Elasticsearch connection settings (SPRING_ELASTICSEARCH_REST_URIS, credentials)
Check that the indexing type matches your setup (FLOWX_INDEXING_TYPE: kafka or http)
If using Kafka indexing, ensure the KAFKA_TOPIC_PROCESS_INDEX_OUT topic exists
Verify the Elasticsearch index name and shard configuration are valid

High memory usage

Symptoms: The process-engine pod experiences OOM kills or high memory consumption.Solutions:

Review Redis caching configuration — large process definitions and compiled scripts are cached in Redis
Check ADVANCING_PROCESSINGBUFFERSIZE and ADVANCING_PROCESSINGTHREADS — high values increase memory usage
Ensure the cleanup mechanism is enabled (SCHEDULER_PROCESSCLEANUP_ENABLED) to remove completed process instances
Review Kafka consumer thread counts — each thread consumes memory for message buffering
Monitor the config params cache settings (FLOWX_CACHE_CONFIGPARAMS_MAXENTRIES) and reduce if needed

Redis Configuration

Cache and session configuration including Sentinel and Cluster modes

Elasticsearch Indexing

Configure process instance indexing and search capabilities

Process Instance Archiving

Archive and manage historical process instance data

Access Roles for Processes

Configure role-based access control for process definitions

Documentation Index

​Infrastructure prerequisites

​Dependencies

​Required external services

​Configuration setup

​Database configuration

​PostgreSQL

​Oracle

​MongoDB configuration

​Configuration parameters

​Configuration parameters from environment variables (default)

​Configuration parameters from Kubernetes Secrets and ConfigMaps

​Config params cache

​Authorization & access roles

​Security configuration

​Resource server (opaque-token introspection)

​Service account configuration

​Configuring Kafka

​Kafka connection settings

​Message routing configuration

​Kafka consumer retry settings

​Consumer groups & consumer threads configuration

Configuring a Kafka Producer

Configuring a Kafka Consumer

About consumer groups and threads

Consumer group configuration

Consumer thread configuration

​Configuring Kafka topics

Topic naming configuration

Core engine topics

Topics related to the Task Management plugin

Topics related to the Notification plugin

Topics related to the Document plugin

OPERATIONS_IN request example

BULK_IN request example

Topics related to UI flow session updates

Topics related to the scheduler extension

Topics related to Timer Events

Topics related to the Search Data service

Topics related to the Audit service

Topics related to Elasticsearch indexing

Processes that can be started by sending messages to a Kafka topic

Topics related to Message Events

Topics related to Events-gateway microservice

Topics related to platform components

Inter-service topic coordination

Kafka message size configuration

Kafka authentication (when using SASL_PLAINTEXT)

​Configuring Elasticsearch connection

​Indexing settings

​Configuring file upload size

​Connecting the Advancing controller

​Configuring the Advancing controller

Advancing controller setup

​CAS lib configuration

​Configuring cleanup mechanism

​Managing subprocesses expiration

​Configuring application management

​RBAC configuration

​Ingress and CORS

​Service routes

​CORS configuration

​Script engine configuration

​Stuck token recovery

​Troubleshooting

​Common issues

​Related resources

Redis Configuration

Elasticsearch Indexing

Process Instance Archiving

Access Roles for Processes

Infrastructure prerequisites

Dependencies

Required external services

Configuration setup

Database configuration

PostgreSQL

Oracle

MongoDB configuration

Configuration parameters

Configuration parameters from environment variables (default)

Configuration parameters from Kubernetes Secrets and ConfigMaps

Config params cache

Authorization & access roles

Security configuration

Resource server (opaque-token introspection)

Service account configuration

Configuring Kafka

Kafka connection settings

Message routing configuration

Kafka consumer retry settings

Consumer groups & consumer threads configuration

Configuring Kafka topics

Configuring Elasticsearch connection

Indexing settings

Configuring file upload size

Connecting the Advancing controller

Configuring the Advancing controller

CAS lib configuration

Configuring cleanup mechanism

Managing subprocesses expiration

Configuring application management

RBAC configuration

Ingress and CORS

Service routes

CORS configuration

Script engine configuration

Stuck token recovery

Troubleshooting

Common issues

Related resources