FlowX Engine setup

Infrastructure prerequisites

Before initiating the FlowX.AI Engine, ensure the following infrastructure components are properly installed and configured:

Kafka
Elasticsearch
Database Instance

Dependencies

The FlowX Engine interacts with various components critical for its operation:

Database: Primary storage for the engine. See Database Configuration.
Redis Server: Used for caching purposes. Refer to Redis Configuration.
Kafka: Facilitates messaging and event-driven architecture. Details on Configuring Kafka.

For a microservices architecture, it’s common for services to manage their data via dedicated databases.

Required external services

Redis Cluster: Essential for caching process definitions, compiled scripts, and Kafka responses.
Kafka Cluster: Serves as the communication backbone with external plugins and integration.

Configuration setup

FlowX.AI Engine utilizes environment variables for configuration. Below are the key environment variables you need to configure:

Authorization & access roles

This section outlines the OAuth2 configuration settings for securing the Spring application, including resource server settings, security type, and access authorizations.

Resource server settings (OAuth2 configuration)

Old configuration from < v4.1 releases (will be deprecated in v4.5):

SECURITY_OAUTH2_BASE_SERVER_URL: The base URL for the OAuth 2.0 Authorization Server, which is responsible for authentication and authorization for clients and users, it is used to authorize clients, as well as to issue and validate access tokens.
SECURITY_OAUTH2_CLIENT_CLIENT_ID: A unique identifier for a client application that is registered with the OAuth 2.0 Authorization Server, this is used to authenticate the client application when it attempts to access resources on behalf of a user.
SECURITY_OAUTH2_CLIENT_CLIENT_SECRET: Secret Key that is used to authenticate requests made by an authorization client.
SECURITY_OAUTH2_REALM: Security configuration env var in the Spring Security OAuth2 framework, it is used to specify the realm name used when authenticating with OAuth2 providers.

New configuration, starting from v4.1 release, available below.

Environment variable	Description	Default Value
`SPRING_SECURITY_OAUTH2_RESOURCE_SERVER_OPAQUE_TOKEN_INTROSPECTION_URI`	URI for token introspection to validate opaque tokens	`${security.oauth2.base-server-url}/realms/${security.oauth2.realm}/protocol/openid-connect/token/introspect`
`SPRING_SECURITY_OAUTH2_RESOURCE_SERVER_OPAQUE_TOKEN_CLIENT_ID`	Client ID for token introspection	`${security.oauth2.client.client-id}`
`SPRING_SECURITY_OAUTH2_RESOURCE_SERVER_OPAQUE_TOKEN_CLIENT_SECRET`	Client secret for token introspection	`${security.oauth2.client.client-secret}`

Service account settings

This section contains the environment variables for configuring process engine service account.

Environment Variable	Description	Default Value
`SECURITY_OAUTH2_SERVICE_ACCOUNT_ADMIN_CLIENT_ID`	Client ID for the service account	`flowx-${SPRING_APPLICATION_NAME}-sa`
`SECURITY_OAUTH2_SERVICE_ACCOUNT_ADMIN_CLIENT_SECRET`	Client secret for the service account

More details about the necessary service account can be found here.

Security configuration

Environment variable	Description	Default Value
`SECURITY_TYPE`	Type of security mechanism used	`oauth2`
`SECURITY_BASIC_ENABLED`	Enable basic authentication	`false`
`SECURITY_PUBLIC_PATHS_0`	List of public paths that do not require authentication	`/api/platform/components-versions`
`SECURITY_PUBLIC_PATHS_1`	List of public paths that do not require authentication	`/manage/actuator/health`
`SECURITY_PATH_AUTHORIZATIONS_0_PATH`	Defines a security path or endpoint pattern. It specifies that the security settings apply to all paths under the `"/api/"` path. The `` is a wildcard that means it includes all subpaths under `"/api/"`.	`"/api/**"`
`SECURITY_PATH_AUTHORIZATIONS_0_ROLES_ALLOWED`	Specifies the roles allowed for accessing the specified path. In this case, the roles allowed are empty (""). This might imply that access to the `"/api/**"` paths is open to all users or that no specific roles are required for authorization.	`"ANY_AUTHENTICATED_USER"`

Configuring Kafka

Kafka handles all communication between the FlowX.AI Engine and external plugins and integrations. It is also used for notifying running process instances when certain events occur.

Kafka connection settings

Environment Variable	Description	Default Value
`SPRING_KAFKA_BOOTSTRAP_SERVERS`	Kafka bootstrap servers	`localhost:9092`
`SPRING_KAFKA_SECURITY_PROTOCOL`	Security protocol for Kafka	`"PLAINTEXT"`

Kafka consumer retry settings

Environment Variable	Description	Default Value
`KAFKA_AUTH_EXCEPTION_RETRY_INTERVAL`	Interval between retries after `AuthorizationException` is thrown.	`10`

Consumer groups & consumer threads configuration

Both a producer and a consumer must be configured:

Configuring a Kafka Producer

Configuring a Kafka Consumer

Consumer groups & consumer threads

In Kafka a consumer group is a group of consumers that jointly consume and process messages from one or more Kafka topics. Each consumer group has a unique identifier called a group ID, which is used by Kafka to manage message consumption and distribution among the members of the group. Thread numbers, on the other hand, refer to the number of threads that a consumer application uses to process messages from Kafka. By default, each consumer instance runs in a single thread, which can limit the throughput of message processing. Increasing the number of consumer threads can help to improve the parallelism and efficiency of message consumption, especially when dealing with high message volumes. Both group IDs and thread numbers can be configured in Kafka to optimize the processing of messages according to specific requirements, such as message volume, message type, and processing latency. The configuration related to consumers (group ids and thread numbers) can be configured separately for each message type as it follows:

Consumer group configuration

Environment Variable	Description	Default Value
`KAFKA_CONSUMER_GROUP_ID_NOTIFY_ADVANCE`	Group ID for notifying advance actions	`notif123-preview`
`KAFKA_CONSUMER_GROUP_ID_NOTIFY_PARENT`	Group ID for notifying when a subprocess is blocked	`notif123-preview`
`KAFKA_CONSUMER_GROUP_ID_ADAPTERS`	Group ID for messages related to adapters	`notif123-preview`
`KAFKA_CONSUMER_GROUP_ID_SCHEDULER_RUN_ACTION`	Group ID for running scheduled actions	`notif123-preview`
`KAFKA_CONSUMER_GROUP_ID_SCHEDULER_ADVANCING`	Group ID for messages indicating continuing advancement	`notif123-preview`
`KAFKA_CONSUMER_GROUP_ID_PROCESS_START`	Group ID for starting processes	`notif123-preview`
`KAFKA_CONSUMER_GROUP_ID_PROCESS_START_FOR_EVENT`	Group ID for starting processes for an event	`notif123-preview`
`KAFKA_CONSUMER_GROUP_ID_PROCESS_EXPIRE`	Group ID for expiring processes	`notif123-preview`
`KAFKA_CONSUMER_GROUP_ID_PROCESS_OPERATIONS`	Group ID for processing operations from Task Management plugin	`notif123-preview`
`KAFKA_CONSUMER_GROUP_ID_PROCESS_BATCH_PROCESSING`	Group ID for processing bulk operations from Task Management plugin	`notif123-preview`

Consumer thread configuration

Environment Variable	Description	Default Value
`KAFKA_CONSUMER_THREADS_NOTIFY_ADVANCE`	Number of threads for notifying advance actions	`6`
`KAFKA_CONSUMER_THREADS_NOTIFY_PARENT`	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_SCHEDULER_ADVANCING`	Number of threads for continuing advancement	`6`
`KAFKA_CONSUMER_THREADS_SCHEDULER_RUN_ACTION`	Number of threads for running scheduled actions	`6`
`KAFKA_CONSUMER_THREADS_PROCESS_START`	Number of threads for starting processes	`6`
`KAFKA_CONSUMER_THREADS_PROCESS_START_FOR_EVENT`	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_BATCH_PROCESSING`	Number of threads for processing bulk operations from task management	`6`

It is important to know that all the events that start with a configured pattern will be consumed by the Engine. This makes it possible to create a new integration and connect it to the engine without changing the configuration.

Configuring Kafka topics

The suggested topic pattern naming convention is the following:

 topic:
    naming:
      package: "ai.flowx."
      environment: "dev."
      version: ".v1"
      prefix: ${kafka.topic.naming.package}${kafka.topic.naming.environment}
      suffix: ${kafka.topic.naming.version}
      engineReceivePattern: engine.receive.

    pattern: ${kafka.topic.naming.prefix}${kafka.topic.naming.engineReceivePattern}*

Environment Variable	Description	Default FlowX.AI value (can be overwritten)
`KAFKA_TOPIC_PROCESS_NOTIFY_ADVANCE`	Kafka topic used internally by the Engine for advancing processes	`ai.flowx.dev.core.notify.advance.process.v1`
`KAFKA_TOPIC_PROCESS_NOTIFY_PARENT`	Kafka topic used for sub-processes to notify the parent process	`ai.flowx.dev.core.notify.parent.process.v1`
`KAFKA_TOPIC_PATTERN`	The topic name pattern that the Engine listens on for incoming events	`ai.flowx.dev.engine.receive.*`
`KAFKA_TOPIC_LICENSE_OUT`	The topic name used by the Engine to generate licensing-related details	`ai.flowx.dev.core.trigger.save.license.v1`

Default parameter (env var)	Description	Default FlowX.AI value (can be overwritten)
`KAFKA_TOPIC_TASK_OUT`	Kafka topic used for sending notifications to the plugin	`ai.flowx.dev.plugin.tasks.trigger.save.task.v1`
`KAFKA_TOPIC_PROCESS_OPERATIONS_IN`	Kafka topic used for receiving calls from the task management plugin with information regarding operations performed	`ai.flowx.dev.core.trigger.operations.v1`
`KAFKA_TOPIC_PROCESS_OPERATIONS_BULK_IN`	Kafka topic where operations can be performed in bulk, allowing multiple operations to be sent at once	`ai.flowx.core.trigger.operations.bulk.v1`

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",
    }
  ]
}

If you need to send additional keys on the response, attach them in the header, as in the following example, where we used requestID key.

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

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

Task manager operations could be the following: assignment, unassignment, hold, unhold, terminate and it is matched with the ...operations.out topic on the engine side. For more information check the Task Management plugin documentation:📄 Task management plugin

Scheduler

Environment variable	Description	Default FlowX.AI value (can be overwritten)
`KAFKA_TOPIC_PROCESS_EXPIRE_IN`	Topic name for requests to expire processes	`ai.flowx.dev.core.trigger.expire.process.v1`
`KAFKA_TOPIC_PROCESS_SCHEDULE_OUT_SET`	Topic name used for scheduling process expiration	`ai.flowx.dev.core.trigger.set.schedule.v1`
`KAFKA_TOPIC_PROCESS_SCHEDULE_OUT_STOP`	Topic name used for stopping process expiration	`ai.flowx.dev.core.trigger.stop.schedule.v1`
`KAFKA_TOPIC_PROCESS_SCHEDULE_IN_RUN_ACTION`	Topic name for requests to run scheduled actions	`ai.flowx.dev.core.trigger.run.action.v1`
`KAFKA_TOPIC_PROCESS_SCHEDULE_IN_ADVANCE`	Topic name for events related to advancing through a database sent by the scheduler	`ai.flowx.dev.core.trigger.advance.process.v1`

Using the scheduler

Environment variable	Description	Default FlowX.AI value (can be overwritten)
`KAFKA_TOPIC_PROCESS_SCHEDULED_TIMER_EVENTS_OUT_SET`	Used to communicate with Scheduler microservice	`ai.flowx.dev.core.trigger.set.timer-event-schedule.v1`
`KAFKA_TOPIC_PROCESS_SCHEDULED_TIMER_EVENTS_OUT_STOP`	Used to communicate with Scheduler microservice	`ai.flowx.dev.core.trigger.stop.timer-event-schedule.v1`

Environment variable	Description	Default FlowX.AI value (can be overwritten)
`KAFKA_TOPIC_DATA_SEARCH_IN`	The topic name that the Engine listens on for requests to search for processes	`ai.flowx.dev.core.trigger.search.data.v1`
`KAFKA_TOPIC_DATA_SEARCH_OUT`	The topic name used by the Engine to reply after finding a process	`ai.flowx.dev.engine.receive.core.search.data.results.v1`

Environment variable	Description	Default FlowX.AI value (can be overwritten)
`KAFKA_TOPIC_AUDIT_OUT`	Topic key for sending audit logs	`ai.flowx.dev.core.save.audit.v1`

Environment variable	Default FlowX.AI value (can be overwritten)
`KAFKA_TOPIC_PROCESS_INDEX_OUT`	ai.flowx.dev.core.index.process.v1

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

Environment variable	Description	Default FlowX.AI value (can be overwritten)
`KAFKA_TOPIC_PROCESS_START_IN`	The Engine listens on this topic for requests to start a new process instance	`ai.flowx.dev.core.trigger.start.process.v1`
`KAFKA_TOPIC_PROCESS_START_OUT`	Used for sending out the reply after starting a new process instance	`ai.flowx.dev.core.confirm.start.process.v1`

Environment variable	Default FLOWX.AI value (can be overwritten)
`KAFKA_TOPIC_PROCESS_EVENT_MESSAGE`	ai.flowx.dev.core.message.event.process.v1
`KAFKA_TOPIC_PROCESS_START_FOR_EVENT`	ai.flowx.dev.core.trigger.start-for-event.process.v1

Environment variable	Description	Default FlowX.AI value (can be overwritten)
`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

Configuring file upload size

The maximum file size allowed for uploads can be set by using the following environment variables:

Environment variable	Description	Default FlowX.AI value (can be overwritten)
`SPRING_SERVLET_MULTIPART_MAX_FILE_SIZE`	Maximum file size allowed for uploads	`50MB`
`SPRING_SERVLET_MULTIPART_MAX_REQUEST_SIZE`	Maximum request size allowed for uploads	`50MB`

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	Example
`SPRING_ELASTICSEARCH_REST_PROTOCOL`	Connection protocol	`https`	`https`
`SPRING_ELASTICSEARCH_REST_URIS`	URL(s) of Elasticsearch nodes (no protocol)	-	`elasticsearch:9200`
`SPRING_ELASTICSEARCH_REST_DISABLESSL`	Disable SSL verification	`false`	`false`
`SPRING_ELASTICSEARCH_REST_USERNAME`	Authentication username	-	`elastic`
`SPRING_ELASTICSEARCH_REST_PASSWORD`	Authentication password	-	`your-secure-password`

For indexing setup, check the Configuring Elasticsearch indexing section.

Connecting the Advancing controller

To use advancing controller, the following env vars are needed for process-engine to connect to Advancing Postgres DB:

Environment variable	Description
`ADVANCING_DATASOURCE_JDBC_URL`	Specifies the connection URL for a JDBC data source, including the server, port, database name, and other parameters
`ADVANCING_DATASOURCE_USERNAME`	Used to authenticate the user’s access to the data source
`ADVANCING_DATASOURCE_PASSWORD`	Sets the password for a data source connection

Configuring the Advancing controller

Environment variable	Description	Default FlowX.AI value (can be overwritten)
`ADVANCING_TYPE`	Specifies the type of advancing mechanism to be used. The advancing can be done either through Kafka or through the database (parallel)	`PARALLEL` (possible values #enum: KAFKA, PARALLEL)
`ADVANCING_THREADS`	Number of parallel threads to be used	`20`
`ADVANCING_PICKING_BATCH_SIZE`	Number of tasks to pick in each batch	`10`
`ADVANCING_PICKING_PAUSE_MILLIS`	Pause duration between picking batches, in milliseconds. After picking a batch of tasks, the system will wait for 100 milliseconds before picking the next batch. This can help in controlling the rate of task intake and processing	`100`
`ADVANCING_COOLDOWN_AFTER_SECONDS`	Cooldown period after processing a batch, in seconds. The system will wait for 120 seconds after completing a batch before starting the next cycle. This can be useful for preventing system overload and managing resource usage	`120`
`ADVANCING_SCHEDULER_HEARTBEAT_CRONEXPRESSION`	A cron expression that defines the schedule for the heartbeat. The scheduler’s heartbeat will trigger every 2 seconds. This frequent heartbeat can be used to ensure the system is functioning correctly and tasks are being processed as expected	`"/2 * * * ?"`

Advancing controller setup

Configuring cleanup mechanism

This section contains environment variables that configure the scheduler’s behavior, including thread count, cron jobs for data partitioning, process cleanup, and master election.

Environment Variable	Description	Default Value	Possible Values
`SCHEDULER_THREADS`	Number of threads for the scheduler	`10`	Integer values (e.g., `10`, `20`)
`SCHEDULER_PROCESS_CLEANUP_ENABLED`	Activates the cron job for process cleanup	`false`	`true`, `false`
`SCHEDULER_PROCESS_CLEANUP_CRON_EXPRESSION`	Cron expression for the process cleanup scheduler	`0 /5 0-5 * ?` -> every day during the night, every 5 minutes, at the start of the minute	Cron expression (e.g., `0 0 1 * * ?`)
`SCHEDULER_PROCESS_CLEANUP_BATCH_SIZE`	Number of processes to be cleaned up in one batch	`1000`	Integer values (e.g., `100`, `1000`)
`SCHEDULER_MASTER_ELECTION_CRON_EXPRESSION`	Cron expression for the master election process	`30 /3 * * ?` -> master election every 3 minutes	Cron expression (e.g., `0 0/3 * * * ?`)

Managing subprocesses expiration

This section details the environment variable that controls the expiration of subprocesses within a parent process. It determines whether subprocesses should terminate when the parent process expires or follow their own expiration settings.

Environment Variable	Description	Default Value	Possible Values
`FLOWX_PROCESS_EXPIRE_SUBPROCESSES`	Governs subprocess expiration in a parent process. When true, terminates all associated subprocesses upon parent process expiration. When false, subprocesses follow their individual expiration settings or persist indefinitely if not configured	`true`	`true`, `false`

Configuring application management

The FlowX helm chart provides a management service with the necessary parameters to integrate with the Prometheus operator. However, this integration is disabled by default.

Old configuration from < v4.1 releases (will be deprecated in v4.5):

MANAGEMENT_METRICS_EXPORT_PROMETHEUS_ENABLED: Enables or disables Prometheus metrics export.

New configuration, starting from v4.1 release, available below. Note that this setup is backwards compatible, it does not affect the configuration from v3.4.x. The configuration files will still work until v4.5 release.

To configure Prometheus metrics export for the FlowX.AI Engine, the following environment variable is required:

Environment Variable	Description	Default Value	Possible Values
`MANAGEMENT_PROMETHEUS_METRICS_EXPORT_ENABLED`	Enables or disables Prometheus metrics export.	`false`	`true`, `false`

Microservices

Plugins

Observability

Microservices access rights

Plugins access rights

FlowX Engine setup

Infrastructure prerequisites

Dependencies

Required external services

Configuration setup

Authorization & access roles

Resource server settings (OAuth2 configuration)

Service account settings

Security configuration

Configuring Kafka

Kafka connection settings

Kafka consumer retry settings

Consumer groups & consumer threads configuration

Configuring a Kafka Producer

Configuring a Kafka Consumer

Consumer groups & consumer threads

Consumer group configuration

Consumer thread configuration

Configuring Kafka topics

OPERATIONS_IN request example

BULK_IN request example

Using the scheduler

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

Configuring file upload size

Configuring Elasticsearch connection

Connecting the Advancing controller

Configuring the Advancing controller

Advancing controller setup

Configuring cleanup mechanism

Managing subprocesses expiration

Configuring application management

Microservices

Plugins

Observability

Microservices access rights

Plugins access rights

​Infrastructure prerequisites

​Dependencies

​Required external services

​Configuration setup

​Authorization & access roles

​Resource server settings (OAuth2 configuration)

​Service account settings

​Security configuration

​Configuring Kafka

​Kafka connection settings

​Kafka consumer retry settings

​Consumer groups & consumer threads configuration

Configuring a Kafka Producer

Configuring a Kafka Consumer

​Consumer groups & consumer threads

​Consumer group configuration

​Consumer thread configuration

​Configuring Kafka topics

​Topics related to the Task Management plugin

​OPERATIONS_IN request example

​BULK_IN request example

​Topics related to the scheduler extension

Using the scheduler

​Topics related to Timer Events

​Topics related to the Search Data service

​Topics related to the Audit service

​Topics related to ES indexing

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

​Topics related to Message Events

​Topics related to Events-gateway microservice

​Configuring file upload size

​Configuring Elasticsearch connection

​Connecting the Advancing controller

​Configuring the Advancing controller

Advancing controller setup

​Configuring cleanup mechanism

​Managing subprocesses expiration

​Configuring application management

Infrastructure prerequisites

Dependencies

Required external services

Configuration setup

Authorization & access roles

Resource server settings (OAuth2 configuration)

Service account settings

Security configuration

Configuring Kafka

Kafka connection settings

Kafka consumer retry settings

Consumer groups & consumer threads configuration

Consumer groups & consumer threads

Consumer group configuration

Consumer thread configuration

Configuring Kafka topics

Topics related to the Task Management plugin

OPERATIONS_IN request example

BULK_IN request example

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 ES indexing

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

Topics related to Message Events

Topics related to Events-gateway microservice

Configuring file upload size

Configuring Elasticsearch connection

Connecting the Advancing controller

Configuring the Advancing controller

Configuring cleanup mechanism

Managing subprocesses expiration

Configuring application management