MarloweScan

MarloweScan is a tool that allows you to explore on-chain Marlowe contracts and watch their execution in Marlowe terms. This document provides instructions on how to build and develop the MarloweScan tool.

Marlowe Runtime compatibility

This version of MarloweScan requires a running instance of the Marlowe Runtime. The compatible versions of the Marlowe Runtime include from 0.0.4 up to and including 0.0.6.

Using Nix

This repo provides a flake.nix file that can be used for developing and building MarloweScan without having to worry about dependencies.

Building with Nix

To build MarloweScan with Nix, you can use the nix command:

nix build

The resulting executable will be made available in result/bin/marlowe-scan-exe

Alternatively, you can run MarloweScan directly by writing:

nix run

Development shell

As usual, you can use the nix command to enter the development environment from the root folder of the project:

nix develop

That will make the required Haskell libraries, tools like cabal, stack, the Haskell Language Server, and the fix-hie command available in the command line.

Caching dependencies

In order to take advantage of caching, you can use the https://nixos.org/channels/nixos-23.05 channel.

Using Stack

To build MarloweScan with Stack you just need to write:

stack build

To run MarloweScan with Stack, you can use the following command:

stack exec marlowe-scan-exe

Both these things can be done from within the development environment, and it will set up Stack for you.

Using Cabal

To build MarloweScan with Cabal, you can use the following command:

cabal build

To run MarloweScan with Cabal, you can use the following command:

cabal run

Both these things can be done from within the development environment, and it will set up Cabal for you.

Updating hie.yaml

If you add or move or rename Haskell modules, you will need to update the hie.yaml file, which is used by the Haskell Language Server (HLS), you can use the following command from within the Nix shell and the marlowe-scan root folder:

fix-hie

From outside of the development shell, it can be updated using the following command instead:

gen-hie --stack > hie.yaml

Please note that hie.yaml files located outside of the project folder (in ancestor folders) may interfere with HLS.

Executable parameters

MarloweScan provides the following flags that can be used to configure its behavior:

• --title-label TEXT: The label to be shown together with the title in the MarloweScan in parenthesis. (It can be used to display the name of the network that MarloweScan is deployed to.) The default value is Preprod.

• --marlowe-scan-port PORT: The port number to use for the MarloweScan server. The default value is 8081.

• --runtime-host HOSTNAME-OR-IP: The hostname or IP address of the running Marlowe Runtime server. The default value is builder.

• --runtime-port PORT: The port number of the running Marlowe Runtime server. The default value is 8080.

• --block-explorer HOST: The hostname or IP address for exploring Cardano blockchain addresses, transactions, etc. The default value is "preprod.cardanoscan.io".

These flags can be set by using the command line when starting the MarloweScan server. For example, to start the server on port 9000 and connect to a runtime server running Preview on the IP address 192.168.0.1 and port 8888, you could use the following command:

result/bin/marlowe-scan-exe --title-label "Preview" --marlowe-scan-port 9000 --runtime-host 192.168.0.1 --runtime-port 8888 --block-explorer "preview.cardanoscan.io"

If you have built the project using Stack you can pass the parameters by adding -- between the command and the parameters, like this:

stack exec marlowe-scan-exe -- --title-label "Preview" --marlowe-scan-port 9000 --runtime-host 192.168.0.1 --runtime-port 8888 --block-explorer "preview.cardanoscan.io"