repository·2.x·Indexed 12 days ago
https://github.com/apache/incubator-seataA distributed transaction solution for microservices designed to ensure data consistency across distributed environments. It utilizes three primary roles—Transaction Coordinator (TC), Transaction Manager (TM), and Resource Manager (RM)—to manage global transactions via a unique XID. Supports multiple transaction modes including AT and TCC, and provides a visual graph designer for Saga StateMachines.
Seata 1.5.0 introduced several key capabilities for distributed transaction management, including:
BusinessActionContext in the try method.redisLocker in Lua mode.application.yaml.edas-hsf and brpc-java.Seata 1.4.2 introduced several new capabilities for transaction management and infrastructure support:
undo_loge compression mode to reduce storage overhead.redis sentinel storage mode.seata server thread pool parameter configuration.acl-token when using Consul as a registry and configuration center.apolloService and apolloCluster.Zookeeper.Nacos dataId.DB and Redis storage modes.seata-server logs to Logstash or Kafka.Seata 1.6.0 introduced several key features for expanded environment support and enhanced transaction modes:
nclob types, and MySQL update join SQL.seata-server now supports multiple registries. Added support for Apache Dubbo3 and Nacos contextPath.seata-client supports JDK 17, and Dockerfiles now support arm64 architectures.The 2.6.0 release introduces several significant capabilities:
HttpClient to support h2c. Added an HTTP request filter for seata-server.fory serializer and fory undolog parser (replacing fury).Seata uses dynamic proxies to manage TCC services. When the GlobalTransactionScanner detects a TCC service 'reference', it applies a dynamic proxy to it.
The primary functions of the TCC dynamic proxy are:
The designer uses a provider pattern to populate UI elements from the diagram-js toolbox:
PaletteProvider: Controls the left-side palette. It defines which elements (e.g., ServiceTask, Fail, Success, Start) can be dragged onto the canvas. It also provides a lasso tool for bulk selection.ContextPadProvider: Controls the contextual menu that appears when an element is selected. For example, it provides 'connect' and 'delete' actions for Shapes, and only 'delete' for Edges.Seata manages distributed transactions through three primary roles and a specific lifecycle involving a Global Transaction ID (XID):
begin, commit, or rollback operations.seata-integration-tx-api module provides an integration layer for TCC (Try-Confirm-Cancel) transactions. This module allows for transaction process definition and proxy enhancement, enabling more structured API access to the TCC workflow.TCC (Try-Confirm-Cancel) is a transaction resource type in Seata that follows a two-phase commit (2PC) protocol. Unlike the AT mode which is automatic, TCC requires the developer to manually implement the business logic for three distinct operations based on their specific business scenario:
Try phase. Requirement: If Try succeeds, Confirm must be guaranteed to succeed.Try phase.The Seata Transaction Manager coordinates these calls: it invokes Try in the first phase, and then invokes either Confirm (for commit) or Cancel (for rollback) in the second phase.
The diagram-js data model is composed of Shape and Connection elements:
Connections.source and target (both being Shape elements).The ElementRegistry creates these based on the model, and the Modeling service updates their relationships during user interaction.
diagram-js uses an event-driven architecture. You can access the eventBus service from the diagram instance to subscribe to lifecycle events, such as modeling changes or element updates.
commandStack.changed to detect when a user performs a modeling operation or an undo/redo action.element.changed to detect when a specific element is modified.diagram.get('eventBus').on('commandStack.changed', () => {
// User modeled something or
// performed an undo/redo operation
});
modeler.on('element.changed', (event) => {
const element = event.element;
// The element was changed by the user
});