[Constructor] Rosetta Constructor DSL

[patrick-ogrady]

Relates: coinbase/mesh-cli#137

This PR adds a simple DSL (domain-specific language) for writing Workflows. For now, we are just calling this Rosetta Constructor DSL but we could introduce a name for this "language" if it gets more sophisticated.

Old Way

[
  {
    "name": "request_funds",
    "concurrency": 1,
    "scenarios": [
      {
        "name": "find_account",
        "actions": [
          {
            "input": "{\"symbol\":\"tBTC\", \"decimals\":8}",
            "type": "set_variable",
            "output_path": "currency"
          },
          {
            "input": "{\"minimum_balance\":{\"value\": \"0\", \"currency\": {{currency}}}, \"create_limit\":1}",
            "type": "find_balance",
            "output_path": "random_account"
          }
        ]
      },
      {
        "name": "request",
        "actions": [
          {
            "type": "load_env",
            "output_path": "min_balance",
            "input": "MIN_BALANCE"
          },
          {
            "type": "math",
            "ouput_path": "adjusted_min",
            "input": "{\"operation\":\"addition\", \"left_value\": {{min_balance}}, \"right_value\": \"600\"}"
          },
          {
            "input": "{\"account_identifier\": {{random_account.account_identifier}}, \"minimum_balance\":{\"value\": {{adjusted_min}}, \"currency\": {{currency}}}}",
            "type": "find_balance",
            "output_path": "loaded_account"
          }
        ]
      }
    ]
  },
  {
    "name": "create_account",
    "concurrency": 1,
    "scenarios": [
      {
        "name": "create_account",
        "actions": [
          {
            "input": "{\"network\":\"Testnet3\", \"blockchain\":\"Bitcoin\"}",
            "type": "set_variable",
            "output_path": "network"
          },
          {
            "input": "{\"curve_type\": \"secp256k1\"}",
            "type": "generate_key",
            "output_path": "key"
          },
          {
            "input": "{\"network_identifier\": {{network}}, \"public_key\": {{key.public_key}}}",
            "type": "derive",
            "output_path": "account"
          },
          {
            "input": "{\"account_identifier\": {{account.account_identifier}}, \"keypair\": {{key}}}",
            "type": "save_account"
          }
        ]
      }
    ]
  }
]

New Way

request_funds(1){ 
  find_account{
    currency = {
      "symbol":"tBTC",
      "decimals":8
    };
    random_account = find_balance({
      "minimum_balance":{
        "value": "0",
        "currency": {{currency}}
      }, 
      "create_limit":1
    });
  },
  request{
    min_balance = load_env("MIN_BALANCE");
    adjusted_min = {{min_balance}} + 600;
    loaded_account = find_balance({
      "account_identifier": {{random_account.account_identifier}},
      "minimum_balance":{
        "value": {{adjusted_min}},
        "currency": {{currency}}
      }
    });
  }
}

create_account(1){
  create_account{
    network = {"network":"Testnet3", "blockchain":"Bitcoin"};
    key = generate_key({"curve_type":"secp256k1"});
    account = derive({
      "network_identifier": {{network}},
      "public_key": {{key.public_key}}
    });
    save_account({
      "account_identifier": {{account.account_identifier}},
      "keypair": {{key}}
    });
  }
}

Changes

• Create a DSL
• recognize set_variable or just equal
• Write language rules in README (at most 1 function call per line)
• Add README for constructor package
• Add constructor to top level README
• Add context for all calls
• Populate custom error with last line read and line number
• Create typed errors
• Add native Math parsing
• ensure referenced variables exist
  • Add previous scenario names to variable map
• Ensure Workflows don't have same names
• Ensure Scenarios don't have same name

Future PR

To build a wallet using this DSL, all you need to do is populate state with some values from a request before running.

[heimdall-asguard]

If Heimdall is stuck, please click the following link: https://heimdall-public.cbhq.net/v1/pull_request/stuck?pr_number=176&repository=coinbase/rosetta-sdk-go

[coveralls]

Pull Request Test Coverage Report for Build 8526

• 299 of 319 (93.73%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.6%) to 78.415%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
constructor/dsl/dsl.go	36	39	92.31%
constructor/dsl/parser.go	256	273	93.77%

Totals
Change from base Build 8217:	0.6%
Covered Lines:	6521
Relevant Lines:	8316

---

💛 - Coveralls

[qiwu7]

🚀 🔥 this is awesome! great documentation on this :)