Does composer have its own concept of consensus or it depends on the underlying fabric consensus which only comes up with the agreed order of transaction ?
Composer doesn't have it's own concept of consensus.
As Composer interacts with Hyperledger Fabric it is subject to the same policies as any other deployed chaincode so will be subject to whatever consensus implementation is being utilized by the underlying hyperledger fabric.
Related
I am new to blockchain and trying Playground for my first Blochain application. I followed this tutorial.
As soon as I click "deploy", I get a pop-up on screen saying "error:error trying install business network. Error: The business network is already installed on all the pears.
Any help will be highly appreciated!!
You would be better off not using hyperledger composer, it's been end of life for a long time and no one uses it and so there won't be anyone who will be able to help you or willing to invest any time to help you. I would suggest you look at hyperledger fabric (which hyperledger composer used to require to provide the blockchain capability as hyperledger composer is not a blockchain technology but an application framework).
https://hyperledger-fabric.readthedocs.io/en/latest/
Also this guide may be useful
https://github.com/hyperledger/fabric-samples/tree/main/full-stack-asset-transfer-guide
I'm new to Hyperledger Fabric, I am using Hyperledger Fabric v2.4 and want to get external data via oracle, I was trying to use provable(previosly known as oraclize) but in the Provable doc, it seems to be only support the Hyperledger v1.2, is there any other oracle that support Hyperledger Fabric v2.4?
I have found chainlink, but chainlink's document doesn't seems to mentioned about Hyperledger Fabric. Is chainlink a feasible solution?
Can anyone give me some direction or advice? I will be really appreciate!
I'm new to Blockchain. I heard that blockchain provides individual ledgers for individual participants. I want to know how it will work with Hyperledger Composer Blockchain application.
Hyperledger Composer is built on Hyperledger Fabric - which is a permissioned, distributed, shared ledger.
If you are new to Composer, I would suggest working through the documentation, in particular the tutorials.
More information on Fabric is available in the Fabric documentation.
I saw that Hyperledger composer is really easy to work with, also we can deploy the composer code on hyperledger fabric. But I found that they create only one channel, and we will have the flexibility to talk to the specific peers like what we can do in GoLang\fabric, can we call external web services from composer java script code as we can do in Golang on fabric?
I'm wondering, can we use hyperledger composer for enterprise blockchain applications? or just we use it to create blockchain POCs.
Regards.
Bassel Kh
Hyperledger Composer is intended to be used for enterprise blockchain applications, although Composer Playground is not intended for Production use.
Composer connects with Fabric using Business Network Cards, and these contain credentials and a Connection Profile. The connection profile contains definitions of the 'services' on the Fabric, and so it is possible to define specific Peers within the card.
Regarding channels - it is again the Connection Profile that determines the Channel used, and at the moment only one channel is supported per Card. Multiple cards can be used but disconnect/switch/re-connect might not be practical or desirable in some cases.
There is a way to connect to a different Business Network on a different Channel covered in this tutorial, but again it might not be suitable for all cases.
There is an outstanding issue on GitHub for using Composer for multi-channel, so you can leave a comment or +1 on it - particularly if you have a good use case for multi-channel.
Many people are thinking of and using channels as a security feature, but Composer ACLs might solve that issue in some cases. Similarly the upcoming sidedb feature in Fabric might offer security instead of separate channels.
yes, you can call external web services and get the results back into your smart contract code or client see -> https://hyperledger.github.io/composer/latest/integrating/call-out
yes Hyperledger Composer is intended for Enterprise blockchain applications. Your applications will use Composer client to write application data to the ledger, and its production runtime is where the 'chaincode' smart contract/business network is deployed/installed on the peers (just like Go chaincode is similarly deployed). One such provider using Composer is here -> https://ibm-blockchain.github.io/platform-deployment/
Finally also see here -> https://github.com/hyperledger/composer-knowledge-wiki/blob/latest/knowledge.md#production for more info.
How are users of Fabric Composer able to see and understand the chain code generated for transactions on their business network?
Fabric Composer does not directly generate chaincode. It uses a generic chaincode that maps models to chaincode tables and runs transaction processor functions in the javascript interpreter for GO, Otto.
The generic chaincode is here