Examples with TransactionContext org.apache.ratis.statemachine.TransactionContext used on opensource projects

Example 1 with TransactionContext

use of org.apache.ratis.statemachine.TransactionContext in project incubator-ratis by apache.

the class RaftServerImpl method submitClientRequestAsync.

@Override
public CompletableFuture<RaftClientReply> submitClientRequestAsync(RaftClientRequest request) throws IOException {
    assertLifeCycleState(RUNNING);
    LOG.debug("{}: receive client request({})", getId(), request);
    if (request.is(RaftClientRequestProto.TypeCase.STALEREAD)) {
        return staleReadAsync(request);
    }
    // first check the server's leader state
    CompletableFuture<RaftClientReply> reply = checkLeaderState(request, null);
    if (reply != null) {
        return reply;
    }
    // let the state machine handle read-only request from client
    final StateMachine stateMachine = getStateMachine();
    if (request.is(RaftClientRequestProto.TypeCase.READ)) {
        // See the RAFT paper section 8 (last part)
        return processQueryFuture(stateMachine.query(request.getMessage()), request);
    }
    // query the retry cache
    RetryCache.CacheQueryResult previousResult = retryCache.queryCache(request.getClientId(), request.getCallId());
    if (previousResult.isRetry()) {
        // future
        return previousResult.getEntry().getReplyFuture();
    }
    final RetryCache.CacheEntry cacheEntry = previousResult.getEntry();
    // TODO: this client request will not be added to pending requests until
    // later which means that any failure in between will leave partial state in
    // the state machine. We should call cancelTransaction() for failed requests
    TransactionContext context = stateMachine.startTransaction(request);
    if (context.getException() != null) {
        RaftClientReply exceptionReply = new RaftClientReply(request, new StateMachineException(getId(), context.getException()), getCommitInfos());
        cacheEntry.failWithReply(exceptionReply);
        return CompletableFuture.completedFuture(exceptionReply);
    }
    return appendTransaction(request, context, cacheEntry);
}