I understand that chaincode(smart contracts) on hyperledger-fabric can be written using golang. But the other thing I see as of fabric 1.0 is the composer - where I could write the 'transactions' part using JS.
Is the difference that go APIs give me more lower level controls like access to MSP and CA and others? Or is it that the newer version would want you to write all your code using JS?
I am looking for some clarification on specific uses of each approach.
This tutorial -> https://blog.selman.org/2017/07/08/getting-started-with-blockchain-development/ should help you with the side-by-side comparison and the approaches using either toolset.
Updated answer (as promised in previous post): Hyperledger Composer v0.19.0 (time of writing - Apr 1st 2018) is the default release for building your blockchain business networks using Composer. So when you pull HL/Composer eg via npm install etc) - this uses the current GA edition of Hyperledger Fabric v1.1, the underlying blockchain network infrastructure. This 0.19.0 release includes a fundamental change in the way that Composer business networks are deployed (vis-a-vis previous releases eg 0.16.x - 0.18.x). Business networks are now deployed within Hyperledger Fabric 'as chaincode' - meaning that the business network (rather than Composer runtime) can be agreed by all parties (to the blockchain network) and signed, using a similar management model to non-Composer chaincode. In a later edition, the plan is to add JS requires so that these can be exploited in NodeJS and include other JS functions you've developed - of course, you can already call native Fabric APIs/chaincode functions already, from Composer transaction processors - introduced prior to 0.19.x release). See more info here in the release notes -> https://github.com/hyperledger/composer/releases/tag/v0.19.0
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I'm trying develop my first Hyperledger fabric application. I'm really confused ,should one use fabric-client or fabric-network or fabric-gateway for developing client SDK in node?
If you are (or can be) using Fabric v2.4 or later, I would strongly recommend using fabric-gateway. If using an older version of Fabric (or if you require some capabilities not available in fabric-gateway) then fabric-network. I would suggest avoiding fabric-client, which is end-of-life after Fabric v1.4.
There is some information on the positioning of the different client API implementation in the Hyperledger Fabric documentation:
https://hyperledger-fabric.readthedocs.io/en/release-2.4/sdk_chaincode.html
I have developed a system using Hyperledger Fabric peer version 2.2.2 hence I need to test the performance (i.e. latency, throughput etc.) of this system using Hyperledger Caliper. I'm new with Blockchain and found it hard to integrate my network with Caliper! Which version of caliper will be suitable for fabric 2.2.2? How can I carry out this whole integration procedure?
This linked tutorial series on youtube will guide you.
You should use caliper 0.4.2 as this supports 2.2.2. I would suggest you follow the tutorial first here https://hyperledger.github.io/caliper/v0.4.2/fabric-tutorial/tutorials-fabric-existing/
As you have created your own fabric network you should be able to construct your own appropriate connection profiles which caliper requires.
If you plan to run caliper on a different machine to the one that contains your network then be aware of the need to disable the localhost default of true as described in the runtime settings on this page https://hyperledger.github.io/caliper/v0.4.2/fabric-config/new/#introducing-the-new-fabric-connector.
I am developing a business network with hyperledger composer. I have followed the tutorial on composer web site at composer playground and have made the tutorial-network as well. Now I am facing one issue. after finishing defining your business network, how is it possible to get the underlying Fabric code that is generated? I can't think of a reason why it should be necessary to have it directly, but lets say if for any reason, like having to give Fabric code to your customer for whom you have developed a poc, you need to have that. Is Fabric code being saved somewhere? I have looked into the business network folder; there are only subfolders for models, test, the business network itself, and after you generate the archive file there is only one file with .bna extension. Nothing related to Fabric there!
I appreciate your help.
As part of the deployment of your business network, an associated Composer runtime is included that can parse model files, query file and acl files, it is also capable of executing your transaction processor functions. In 0.16.x this was achieved by including a JavaScript VM implementation using Go Chaincode to execute the Composer runtime (written in JavaScript) and the transaction processor functions. In Fabric 1.1, chaincode can be written natively as it now supports Node.js chaincode so with Composer beyond 0.16.x (currently 0.19.x at the time of writing) Composer utilizes this and all Go chaincode it used to contain was removed, along with the Javascript VM. It's the composer runtime that parses the model, query and acl files, and the transaction processor functions run natively inside the node.js fabric chaincode container. Nothing is ever compiled to Go.
The smart contract will be saved in different manner in fabric, as composer is just an abstraction over it. You need to search for the location where the chaincode is present inside the peer. There are some chaincode related commands which can help you in finding out where the chain code is installed. And to the client you can give the .bna file if you are using composer for the development because I am not sure whether the code will be easily readable at fabric level if you are using composer.
I am new to hyperledger and bit confused about hyperledger composer & nodejs api.
I saw using composer we can create assets, transactions, participants and chaincode and in last we have to archive it this all into .bna file and finally we deploy this chaincode into network using admin card
But at other end using NodeJs API we can also write chaincode by overiding init & invoke methods.
How can we relate these all.
The best way to think about this is the following:
1) Hyperledger Fabric v1.1 supports writing chaincode in two languages: Golang and JavaScript via Node.js
If you want to do all of the heavy lifting yourself, you can write straight chaincode.
2) Hyperledger Composer provides a higher-level model-driven language for developing smart contracts. It currently only allows deployment of these artifacts to Hyperledger Fabric. It also happens to support writing functions in JavaScript as well.
So if you want to start from a higher-level model-driven approach, Hyperledger Composer is the way to go. If you want to write all of the plumbing yourself or use very low-level chaincode features, then using chaincode itself is the way to go.
Moving forward, we are looking at a better way to move between the two and not force a decision / direction up front.
There is another option, we develop a framework called Convector to be in the middle of Composer (high abstraction, low control) and raw code (low abstraction, high control, therefore high risk). We open sourced it a few days ago. At WorldSibu we don't like loosing so much control over our code like with Composer but as Gari Singh was saying, doing all the heavy lifting for each project is crazy. It is like a Mongoose for Hyperledger Fabric. It may help to check it out.
It is also worth noting that, according to IBM, Composer is no longer recommended as a production solution, but only for prototyping. In HLF 1.3, chaincode can now be written in Go, Javascript and Java.
Other than the fact that Composer makes deployment and testing of prototype business networks easier and the fact that we don't have to know golang to develop chaincode, what is the difference in the functionalities that these interfaces provide that may lead one to choose one over the other?
This article can probably provide you with the answers you need:
https://blog.selman.org/2017/07/08/getting-started-with-blockchain-development/
Hyperledger Composer is both an application development framework and set of powerful tools which simplifies and expedites the creation of blockchain applications and smart contracts that are ultimately executed on the Hyperledger Fabric blockchain. Composer has its own runtime, that is generic chaincode and hosts and interprets the business network deployed - so your smart contract need only use Javascript, not chaincode in Go a (which is Fabric's domain) s you mentioned. It also has a modeling facility to create your business network model and to define such controls as Access Control lists and queries to be executed.
This architecture link should help you with further understanding -> https://www.slideshare.net/SimonStone8/hyperledger-composer-architecture
Furthermore see the Hyperledger Composer docs, see here:
https://hyperledger.github.io/composer/
TO see the Hyperledger Fabric docs - see here:
https://hyperledger-fabric.readthedocs.io/en/latest/