Flogo extension for Hyperledger Fabric chaincode

This Flogo extension is designed to allow developers to design and implement Hyperledger Fabric chaincode in the Flogo visual programming environment. This extension supports the following release versions:

• Flogo Web UI
• Hyperledger Fabric 2.2

The Transaction Trigger starts chaincode transactions for requests containing preconfigured input parameters and/or transient data.

The Flogo extension supports the following activities for storing and querying data in the distributed ledger and/or in private data collections.

• Put: Insert or update one or more records in the distributed ledger or a private data collection, and optionally update associated compsite keys.
• Get: Retrieve one or more records corresponds to state keys or composite keys in the distributed ledger or a private data collection, including execution of range query or couchdb rich query, as well as fetching history of states of specified state keys.
• Delete: Mark the state as deleted for one or more state keys in the distributed ledger or a private data collection, and delete its associated composite keys. Optionally, it can delete only the state, or only a composite key.
• Set Event: Set a specified event and payload for a blockchain transaction.
• Set Endorsement Policy: Set state-based endorsement policy by adding or deleting an endorsement organization, or by specifying a new endorsement policy.
• Invoke Chaincode: Invoke a local chaincode, and returns response data from the called transaction.

With these Flogo extensions, Hyperledger Fabric chaincode can be designed and implemented by using the Flogo Web UI with zero code.

Getting Started

For Golang developers on Mac or Linux, you can setup the full development environment locally as follows:

• Download and setup Golang from here.
• Clone this repo into an empty working directory: git clone https://github.com/open-dovetail/fabric-chaincode.git
• Setup development environment by executing the script: scripts/setup.sh
• Build and run a sample Flogo model marble as described in README.md

Other developers can follow the instructions in the demo that uses prebuilt Docker images to build Dovetail applications. This approach requires installation of only Docker and docker-compose, and should work in any platform that supports Docker.

Write smart contract in JSON

For smart contract developers who do not want to code, you can define chaincode transactions in a JSON file, and then use the Flogo CLI command to generate a Flogo app and build it into a chaincode package that can be deployed and run in a Fabric network.

All you need to do is to provided a JSON specification of a contract, and then optionally edit the data mapping via drag-and-drop in either the open-source Flogo Web-UI or the more advanced TIBCO Flogo Enterprise Web-UI. Thus, you can implement a Fabric chaincode without any programming in Java, Go, nor JavaScript.

The contract example shows the JSON schema for smart contract and a sample contract that you can build and test using the Fabric test-network.

The demo contract shows the same build process and steps to build artifacts by using preconfigured Docker containers.

View and edit Flogo model

To view and edit the chaincode implementation in a web-browser, you can start a Flogo Web UI that is preconfigured with Dovetail extensions:

docker run -it -p 3303:3303 yxuco/flogo-ui eula-accept

or, you can start the most recent release of Flogo Web UI and then install required Dovetail extensions:

docker run -it -p 3303:3303 flogo/flogo-docker eula-accept

Open the Flogo Web UI in a web-browser by using the URL: http://localhost:3303.

Install the following Dovetail contributions, i.e., click the link Install contribution at the top-right corner of the UI, and then enter the following URL to install. If the installation fails, you can follow the Troubleshoot steps below to patch Flogo libs, and then retry the installation.

• github.com/open-dovetail/fabric-chaincode/trigger/transaction
• github.com/open-dovetail/fabric-chaincode/activity/put
• github.com/open-dovetail/fabric-chaincode/activity/get
• github.com/open-dovetail/fabric-chaincode/activity/delete
• github.com/project-flogo/contrib/activity/noop

You can then import a sample app by selecting the model file samples/marble/marble.json.

Status code

The Dovetail contributions will all return a status code similar to HTTP spec as follows:

• 200 OK
• 201 Created
• 206 Partial Content (e.g., paged result, or not all PUT succeeded)
• 400 Bad Request
• 403 Forbidden (e.g., user authenticated but not authorized)
• 404 Not Found (e.g., query result is empty)
• 409 Conflict (e.g., cannot create record for existing key when createOnly=true)
• 500 Internal Server Error (e.g., unexpected exception in chaincode)
• 501 Not Implemented (e.g., transaction name is not configured by trigger)

Troubleshoot

Failed to import Flogo model

Make sure that you have installed required Flogo contributions listed above.

Failed to install dovetail contributions in Web UI

The Dovetail contributions require a couple of Flogo patches that have not yet been merged to the Flogo core/flow projects, and so to install Dovetail contributions in the Web UI, you can make the following changes after you start the Web UI docker container:

First, start a shell in the Web UI docker container:

docker exec -it $(docker ps --filter ancestor=flogo/flogo-docker --format "{{.ID}}") bash

Then, in the docker container shell, change directory to the flogo-web source directory:

cd /flogo-web/local/engines/flogo-web/src

If you need vi editor to edit files in the docker container, you can install it as follows:

apt update
apt install vim

Then, you can add the following lines to the end of the file go.mod:

replace github.com/project-flogo/flow => github.com/yxuco/flow v1.1.1
replace github.com/project-flogo/core => github.com/yxuco/core v1.2.2

This will make the Flogo Web UI to use the Flogo fork containing the patches required by the Dovetail contributions.