Add invoke_system_call

[youkaicountry]

Resolves #799

Brief description

Add invoke_system_call

Checklist

• I have built this pull request locally
• I have ran the unit tests locally
• I have manually tested this pull request
• I have reviewed my pull request
• I have added any relevant tests

Demonstration

Invoking system call get_contract_address, using the name koin

curl -d '{"jsonrpc":"2.0", "method":"chain.invoke_system_call", "params":{"id":10001, "args":"CgRrb2lu"}, "id":0}' http://localhost:8080/ | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   208  100    90  100   118  45000  59000 --:--:-- --:--:-- --:--:--  101k
{
  "jsonrpc": "2.0",
  "result": {
    "value": "Ch0KGwoZAC4z_RqpB7IkzpzmyUIokB0oOgLalW2nkQ=="
  },
  "id": 0
}

This protobuf message is a result object containing the proper address.

Here is invoking it using the name of the system call:

curl -d '{"jsonrpc":"2.0", "method":"chain.invoke_system_call", "params":{"name":"get_contract_address", "args":"CgRrb2lu"}, "id":0}' http://localhost:8080/ | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   213  100    90  100   123  45000  61500 --:--:-- --:--:-- --:--:--  104k
{
  "jsonrpc": "2.0",
  "result": {
    "value": "Ch0KGwoZAC4z_RqpB7IkzpzmyUIokB0oOgLalW2nkQ=="
  },
  "id": 0
}

and invoking get_resource_limits via id, then name:

curl -d '{"jsonrpc":"2.0", "method":"chain.invoke_system_call", "params":{"name":"get_resource_limits"}, "id":0}' http://localhost:8080/ | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   185  100    82  100   103  41000  51500 --:--:-- --:--:-- --:--:-- 92500
{
  "jsonrpc": "2.0",
  "result": {
    "value": "ChkKFwiAgCAQkrABGICAQCDUGijgzYuJATAR"
  },
  "id": 0
}


curl -d '{"jsonrpc":"2.0", "method":"chain.invoke_system_call", "params":{"id":203}, "id":0}' http://localhost:8080/ | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   165  100    82  100    83  27333  27666 --:--:-- --:--:-- --:--:-- 55000
{
  "jsonrpc": "2.0",
  "result": {
    "value": "ChkKFwiAgCAQkrABGICAQCDUGijgzYuJATAR"
  },
  "id": 0
}

Invoking with no name or id:

 curl -d '{"jsonrpc":"2.0", "method":"chain.invoke_system_call", "params":{}, "id":0}' http://localhost:8080/ | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   191  100   116  100    75   113k  75000 --:--:-- --:--:-- --:--:--  186k
{
  "jsonrpc": "2.0",
  "error": {
    "code": -32603,
    "message": "Missing system call id or name",
    "data": "{\"code\":-103}"
  },
  "id": 0
}

[sgerbino]

TODO:

• Create a PR for the koinos/koinos-proto changes
• After merge of the koinos/koinos-proto PR, hook this branch up to master
• Provide a manual test of the name_service contract calling get_address on koin
• Provide a manual test of a genesis system call such as get_resource_limits

[sgerbino]

Do we need to handle the case where no ID or name is provided?