emulator

Scalar DL Emulator

Scalar DL Emulator is an interactive command line interface to run Scalar DL on a local mutable in-memory ledger. The emulator may be used to quickly and easily test Scalar DL contracts. It does, however, lack any of the tamper-evident features found in the actual Scalar DL.

Generate an executable

Execute

./gradlew installDist

After a successful run the emulator executable may be found in /build/install/emulator/bin.

Run

To run the emulator

./build/install/emulator/bin/emulator

or pass a file with -f containing a list of commands the emulator will execute. For example, this will run the commands contained in cmds.txt

./build/install/emulator/bin/emulator -f cmds.txt

Exit the emulator

Exit the emulator with exit or by ctrl-d (EOF).

Preregistered contracts

There are three predefined and preregistered contracts, with corresponding commands, to put, get, and scan assets. These contracts may be found in the contract subdirectory

src/main/java/com/scalar/client/tool/emulator/contact

Register a contract

Write a contract and save it in the contract subdirectory

src/main/java/com/scalar/client/tool/emulator/contact

Run ./gradlew build to compile the contract. Then start the emulator and register the contract by using the register command. For example, to register the contract StateUpdater.java with id state-updater

scalar> register state-updater com.scalar.client.tool.emulator.contract.StateUpdater ./build/classes/java/main/com/scalar/client/tool/emulator/contract/StateUpdater.class

Now this contract may be executed, for example, as

scalar> execute state-updater {"asset_id": "Y", "state": 1}"

Help

Type help to display the list of available commands inside the interactive terminal.

scalar> help
Available commands:
 - execute
 - get
 - get -j
 - list-contracts
 - put
 - put -j
 - register
 - scan
 - scan -j
 - help
 - exit
Type '<command> -h' to display help for the command.

Every command has a detailed help that can be displayed with -h. For example:

scalar> execute -h

Usage:
execute [-h] id argument...

Description:
Execute a registered contract.

Parameters:
      id            contract id. Use 'list-contracts' to list all the registered contracts and their ids.
      argument...   the JSON contract argument. A plain text JSON object or the path to a file containing a JSON object

Options:
  -h, --help        print the help and exit

For example: 'execute get {"asset_id": "foo"}'

Command history

A history of executed commands is saved to .scalardl_emulator_history in your home directory.

Any questions?

If you have any questions please contact us.

License

Scalar DL Emulator is dual-licensed under both the AGPL (found in the LICENSE file in the root directory) and a commercial license. You may select, at your option, one of the above-listed licenses. Regarding the commercial license, please contact us for more information.