amqp_trx_plugin - transaction in, transaction_trace out

[heifner]

Change Description

New plugins: amqp_trx_plugin & amqp_trace_plugin

• amqp_trx_plugin
  • Consumes from AMQP 'trx' queue for speculative execution
  • If amqp_trace_plugin enabled then errors are reported via the amqp_trace_plugin. Errors include: too many trx in progress and signature issues.

Binary fc::pack format:

// consume message types
using transaction_msg = fc::static_variant<chain::packed_transaction_v0, chain::packed_transaction>;

• amqp_trace_plugin
  • Publishes transaction trace results to 'trace' queue with CorrelationID set to transaction id.

Binary fc::pack format:

// publish message types
struct transaction_trace_exception {
   int64_t error_code; ///< fc::exception code()
   std::string error_message;
};
using transaction_trace_msg = fc::static_variant<transaction_trace_exception, chain::transaction_trace>;

Change Type

Select ONE

• Documentation

• Stability bug fix

• Other

• Other - special case

Consensus Changes

• Consensus Changes

API Changes

• API Changes

Documentation Additions

• Documentation Additions

eosio::amqp_trx_plugin options

• amqp-trx-address
  • AMQP address: Format: amqp://USER:PASSWORD@ADDRESS:PORT
    Will consume from 'trx' queue

eosio::amqp_trace_plugin options

• amqp-trace-address
  • AMQP address: Format: amqp://USER:PASSWORD@ADDRESS:PORT
    Will publish to 'trace' queue.
• amqp-trace-exchange
  • Existing AMQP exchange to send transaction trace messages.

[spoonincode]

I wonder if the more AMQPy way of doing this would be instead of the amqp-trx-exchange config, leveraging the reply-to field of a message. If you have multiple callers this allows you to send the responses back to the individual caller. I'm guessing it's not a huge problem for us in this case though since a submitter likely knows if a response was intended for itself or someone else because it's expecting a particular trxid.

[swatanabe-b1]

If we use reply-to then we'd still need somewhere to publish transaction traces when amqp-trx-publish-all-traces is on.

[swatanabe-b1]

TBC

[swatanabe-b1]

This is scary, because it leaves the TcpConnection holding a dangling pointer, but it's safe (for now) because the first thing that ~TcpConnection does is to clear its handler.