Intro for new developers

This is a quick introduction to get new developers up to speed on Graphene.

Starting Graphene

git clone https://gitlab.bitshares.org/dlarimer/graphene
cd graphene
git submodule update --init --recursive

TODO: Are recursive flags needed for submodules?

cmake -DCMAKE_BUILD_TYPE=Debug .
make
./programs/witness_node/witness_node

This will launch the witness node. If you would like to launch the command-line wallet, you must first specify a port for communication with the witness node. To do this, add text to witness_node_data_dir/config.json as follows, then restart the node:

"websocket_endpoint": "127.0.0.1:8090"

Then, in a separate terminal window, start the command-line wallet cli_wallet:

./programs/cli_wallet/cli_wallet

If you send private keys over this connection, websocket_endpoint should be bound to localhost for security.

Code coverage testing

TODO: Write something here

Unit testing

TODO: Write something here

Core mechanics

• Witnesses
• Key members
• Price feeds
• Global parameters
• Voting on witnesses
• Voting on key members
• Witness pay
• Transfers
• Markets
• Escrow
• Recurring payments

Gotchas

• Key objects can actually contain a key or address

Witness node

The role of the witness node is to broadcast transactions, download blocks, and optionally sign them.

TODO: How do you get block signing keys into the witness node?

How to use fc async to do recurring tasks

_my_task = fc::async( callable, "My Task" );
_my_task = fc::schedule( callable, "My Task 2", exec_time );

Stuff to know about the code

static_variant<t1, t2> is a union type which says "this variable may be either t1 or t2." It is serializable if t1 and t2 are both serializable (TODO: Is this accurate?)

The 'operations.hppdocuments the available operations, anddatabase_fixture.hpp` shows the way to do many things.

Tests also show the way to do many things, but are often cluttered with code that generates corner cases to try to break things in every possible way.

Visitors are at the end of operations.hpp after the large typedef for operation as a static_variant. TODO: They should be refactored into a separate header.

When using modify(), you can pass in either an object_id or an object. Passing in an object is faster as it avoids a lookup.

Downcasting stuff

• You have an object_id_type and want to downcast it to a key_id_type : key_id_type( object_id )
• You have an operation_result and want to downcast it to an object_id_type : op_result.get<object_id_type>()
• Since operation_result is a static_variant, the above is also how you downcast static_variant

Running specific tests

• tests/chain_tests -t block_tests/name_of_test

Debugging FC exceptions with GDB

• catch throw

TODO: Questions

This section contains questions for more experienced developers to answer.

Is there a way to generate help with parameter names and method descriptions?

Is there a way to allow external program to drive cli_wallet via websocket, JSONRPC, or HTTP?# graphene