WillemJiang closed pull request #275: [SCB-864] add SQL component content into
API document
URL: https://github.com/apache/incubator-servicecomb-saga/pull/275
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diff --git a/docs/api/api.md b/docs/api/api.md
index e0a9e8fc..ef89c222 100755
--- a/docs/api/api.md
+++ b/docs/api/api.md
@@ -166,3 +166,115 @@ curl -XGET http://<docker.host.ip:saga.port>/events
#### Status codes
- **200** – no error
+### Invoke embedded Saga to execute SQL transaction
+
+In order to Invoke embedded saga, it is necessary to add dependencies to your
applications.
+
+There are a `maven` example
+
+```
+<dependencies>
+
+ ...
+
+ <dependency>
+ <groupId>org.apache.servicecomb.saga</groupId>
+ <artifactId>saga-core</artifactId>
+ </dependency>
+ <dependency>
+ <groupId>org.apache.servicecomb.saga</groupId>
+ <artifactId>saga-format</artifactId>
+ </dependency>
+
+ ...
+
+</dependencies>
+```
+
+#### Description
+
+1. Implement SQLTransport interface in your own applications.
+
+2. Instance `SagaExecutionComponent` and inject it into your own applications.
+
+3. Define requests in order and recovery policy by JSON format as below in
your applications.
+
+```
+{
+ "policy": "",
+ "requests": [
+ {
+ "id": "",
+ "type": "",
+ "datasource": "",
+ "parents": [
+
+ ],
+ "transaction": {
+ "sql": "",
+ "params": [
+
+ ]
+ },
+ "compensation": {
+ "sql": "",
+ "params": [
+
+ ]
+ }
+ }
+ ]
+}
+```
+JSON parameters:
+- policy - support `BackwardRecovery` or `ForwardRecovery`.
+- requests - transactions array.
+ - id - request id. It should be unique among this collection of requests.
+ - type - support `sql` for now.
+ - datasource - user-defined datasource name.
+ - parents - request ids. It means this request is only executed after all
requests in the parents field are completed.
+ - transaction - user-defined transaction that executed by the Saga.
+ - sql - user-defined, forward sql.
+ - params - parameters for forward sql.
+ - compensation - user-defined compensation that executed by the Saga.
+ - sql - user-defined, backward sql.
+ - params - parameters for backward sql.
+
+4. Invoke `SagaExecutionComponent.run(String json)` function to execute saga.
+
+#### Example Implement SQLTransport interface
+
+```
+public class ExampleSQLTransport implements SQLTransport {
+ @Override
+ public SagaResponse with(final String datasource, final String sql, final
List<String> params) {
+ try {
+ // invoke your own code to execute sql.
+ } catch (Exception e) {
+ throw new TransportFailedException("execute SQL " + sql + " occur
exception: ", e);
+ }
+ return new JsonSuccessfulSagaResponse("{}");
+ }
+}
+```
+
+#### Example Instance `SagaExecutionComponent`
+
+```
+ private final SQLTransport sqlTransport = new ExampleSQLTransport;
+
+ private final TransportFactory<SQLTransport> transportFactory = new
TransportFactory<SQLTransport>() {
+ @Override
+ public SQLTransport getTransport() {
+ return sqlTransport;
+ }
+ };
+
+ private final SagaExecutionComponent coordinator = new
SagaExecutionComponent(
+ new EmbeddedPersistentStore(),
+ new JacksonFromJsonFormat(transportFactory),
+ null,
+ new GraphBasedSagaFactory(500, eventStore, new ChildrenExtractor(),
Executors.newFixedThreadPool(5))
+ );
+```
+
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