Today Solomon_ Xiao Ge plays the architecture, to talk to you about how XID is delivered in all micro-services, what technology is used to accomplish this task, this question is a frequent question in micro-services interview.
How is distributed transaction XID passed
XID delivery strategy for the Seata framework
Delivery of distributed transaction XIDS in Dubbo
XID context container structure
Dubbo XID integrates core code
“ApacheDubboTransactionPropagationFilter”
@Activate(group = {Constants.PROVIDER, Constants.CONSUMER}, order = 100)
public class TransactionPropagationFilter implements Filter {
@Override
public Result invoke(Invoker
invoker, Invocation invocation) throws RpcException {
// Get the local XID
String xid = RootContext.getXID();
String xidInterceptorType = RootContext.getXIDInterceptorType();
// Get the XID of the implicit Dubbo parameter
String rpcXid = getRpcXid();
String rpcXidInterceptorType = RpcContext.getContext().getAttachment(RootContext.KEY_XID_INTERCEPTOR_TYPE);
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("xid in RootContext[{}] xid in RpcContext[{}]", xid, rpcXid);
}
boolean bind = false;
if(xid ! =null) {
/ / pass XID
RpcContext.getContext().setAttachment(RootContext.KEY_XID, xid);
RpcContext.getContext().setAttachment(RootContext.KEY_XID_INTERCEPTOR_TYPE, xidInterceptorType);
} else {
if(rpcXid ! =null) {
/ / bind XID
RootContext.bind(rpcXid);
RootContext.bindInterceptorType(rpcXidInterceptorType);
bind = true;
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("bind[{}] interceptorType[{}] to RootContext", rpcXid, rpcXidInterceptorType); }}}try {
return invoker.invoke(invocation);
} finally {
if (bind) {
// Perform the XID to exclude completed transactions
String unbindInterceptorType = RootContext.unbindInterceptorType();
String unbindXid = RootContext.unbind();
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("unbind[{}] interceptorType[{}] from RootContext", unbindXid, unbindInterceptorType);
}
// If it is found that the unbound XID is not the currently received XID
if(! rpcXid.equalsIgnoreCase(unbindXid)) { LOGGER.warn("xid in change during RPC from {} to {}, xidInterceptorType from {} to {} ", rpcXid, unbindXid, rpcXidInterceptorType, unbindInterceptorType);
if(unbindXid ! =null) {
// rebind XID
RootContext.bind(unbindXid);
RootContext.bindInterceptorType(unbindInterceptorType);
LOGGER.warn("bind [{}] interceptorType[{}] back to RootContext", unbindXid, unbindInterceptorType);
}
}
}
}
}
/**
* get rpc xid
* @return* /
private String getRpcXid(a) {
String rpcXid = RpcContext.getContext().getAttachment(RootContext.KEY_XID);
if (rpcXid == null) {
rpcXid = RpcContext.getContext().getAttachment(RootContext.KEY_XID.toLowerCase());
}
returnrpcXid; }}Copy the codeSPI integration mode
io.seata.integration.dubbo.ApacheDubboTransactionPropagationFilter
Delivery of distributed transaction Xids in Http
Spring Servlet interceptor integration
Http service XID integration core code
/** * transaction delivery interceptor **/
public class TransactionPropagationIntercepter extends HandlerInterceptorAdapter {
// preprocessing
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
// Context fetch xID
String xid = RootContext.getXID();
// The request header gets the remote XID
String rpcXid = request.getHeader(RootContext.KEY_XID);
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("xid in RootContext[{}] xid in HttpContext[{}]", xid, rpcXid);
}
if(rpcXid ! =null) {
// Context binding
RootContext.bind(rpcXid);
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("bind[{}] to RootContext", rpcXid); }}return true;
}
// post-processing
public void postHandle( HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {
/ / clean up XIDXidResource.cleanXid(request.getHeader(RootContext.KEY_XID)); }}Copy the codeSpring Factory Configuration
SPI integration mode
# Auto Configuration
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
io.seata.integration.http.HttpAutoConfiguration
Copy the codeDelivery of distributed transaction XIDS in Motan
Motan XID integrates core code
@Spi(scope = Scope.SINGLETON)
@Activation(key = {MotanConstants.NODE_TYPE_SERVICE, MotanConstants.NODE_TYPE_REFERER}, sequence = 100)
public class MotanTransactionFilter implements Filter {
public MotanTransactionFilter(a){}
@Override
public Response filter(finalCaller<? > caller,final Request request) {
// Get the existing XID from the context
String currentXid = RootContext.getXID();
// Get the XID passed remotely
String requestXid = getRpcXid(request);
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("xid in RootContext [" + currentXid + "] xid in Request [" + requestXid + "]");
}
boolean bind = false;
if(currentXid ! =null) {
// Get the XID from the request object
request.getAttachments().put(RootContext.KEY_XID, currentXid);
} else if (null! = requestXid) {// Context binding XID
RootContext.bind(requestXid);
bind = true;
}
try {
// Remote call
return caller.call(request);
} finally {
if (bind) {
// Context unbind XID
String unbindXid = RootContext.unbind();
if(! requestXid.equalsIgnoreCase(unbindXid)) {if(unbindXid ! =null) {
RootContext.bind(unbindXid);
LOGGER.warn("bind [" + unbindXid + "] back to RootContext");
}
}
}
}
}
/** * get RPC xid *@param request
* @return* /
private String getRpcXid(Request request) {
String rpcXid = request.getAttachments().get(RootContext.KEY_XID);
if (rpcXid == null) {
rpcXid = request.getAttachments().get(RootContext.KEY_XID.toLowerCase());
}
returnrpcXid; }}Copy the codeSPI integration mode
Interceptor configuration
io.seata.integration.motan.MotanTransactionFilter
Transfer of distributed transaction XID in Sofa- RPC
Sofa- RPC service provider XID integrates core code
@Extension(value = "transactionContextProvider")
@AutoActive(providerSide = true)
public class TransactionContextProviderFilter extends Filter {
@Override
public SofaResponse invoke(FilterInvoker filterInvoker, SofaRequest sofaRequest) throws SofaRpcException {
// Get XID from context
String xid = RootContext.getXID();
// Get the XID from the request
String rpcXid = getRpcXid(sofaRequest);
boolean bind = false;
if(xid ! =null) {
// Set XID from RPC context
RpcInternalContext.getContext().setAttachment(RootContext.KEY_XID, xid);
} else {
if(rpcXid ! =null) {
// Context binding XID
RootContext.bind(rpcXid);
bind = true; }}try {
// Remote call
return filterInvoker.invoke(sofaRequest);
} finally {
if (bind) {
// Context releases XID
String unbindXid = RootContext.unbind();
if(! rpcXid.equalsIgnoreCase(unbindXid)) {if(unbindXid ! =null) {
RootContext.bind(unbindXid);
}
}
}
}
}
/** * get RPC xid *@return* /
private String getRpcXid(SofaRequest sofaRequest) {
String rpcXid = (String) sofaRequest.getRequestProp(RootContext.KEY_XID);
if (rpcXid == null) {
rpcXid = (String) sofaRequest.getRequestProp(RootContext.KEY_XID.toLowerCase());
}
returnrpcXid; }}Copy the codeSofa- RPC service consumer XID integration core code
@Extension(value = "transactionContextConsumer")
@AutoActive(consumerSide = true)
public class TransactionContextConsumerFilter extends Filter {
@Override
public SofaResponse invoke(FilterInvoker filterInvoker, SofaRequest sofaRequest) throws SofaRpcException {
// Get the XID in the existing context
String xid = RootContext.getXID();
// Get the XID from the request
String rpcXid = getRpcXid();
boolean bind = false;
if(xid ! =null) {
// Request the object to get the XID
sofaRequest.addRequestProp(RootContext.KEY_XID, xid);
} else {
if(rpcXid ! =null) {
// Context binding XID
RootContext.bind(rpcXid);
bind = true; }}try {
// Remote call
return filterInvoker.invoke(sofaRequest);
} finally {
if (bind) {
// Context releases the XID binding
String unbindXid = RootContext.unbind();
if(! rpcXid.equalsIgnoreCase(unbindXid)) {if(unbindXid ! =null) {
RootContext.bind(unbindXid);
}
}
}
}
}
/** * get RPC xid *@return* /
private String getRpcXid(a) {
String rpcXid = (String) RpcInternalContext.getContext().getAttachment(RootContext.KEY_XID);
if (rpcXid == null) {
rpcXid = (String) RpcInternalContext.getContext().getAttachment(RootContext.KEY_XID.toLowerCase());
}
returnrpcXid; }}Copy the codeSPI integration mode
io.seata.integration.sofa.rpc.TransactionContextProviderFilter
io.seata.integration.sofa.rpc.TransactionContextConsumerFilter
Copy the codeYour “like” is the best support and motivation for me. Pay attention to Solomon_ Xiao Ge shell structure, follow-up efforts to launch high-quality content.
