fabric-sdk-go error: No peers to connect to

We are using the IBM Managed Blockchain based on fabric 1.2, and using the Go SDK @5e291d3a34f59beb9a8ae2bcbba388515648dc73. When we try to invoke the chaincode we have installed on the peers, we get a "no peers to connect to" error:

We are using the IBM Managed Blockchain based on fabric 1.2, and using the Go SDK @5e291d3a34f59beb9a8ae2bcbba388515648dc73. When we try to invoke the chaincode we have installed on the peers, we get a "no peers to connect to" error:

[fabsdk/fab] 2019/01/25 12:25:57 UTC - dispatcher.(*Dispatcher).Start.func1 -> DEBU Listening for events...
[fabsdk/fab] 2019/01/25 12:25:57 UTC - client.(*Client).connect -> DEBU ... got error in connection response: no peers to connect to
[fabsdk/common] 2019/01/25 12:25:57 UTC - retry.(*RetryableInvoker).Invoke -> DEBU Failed with err [error registering for TxStatus event: no peers to connect to] on attempt #1. Checking if retry is warranted...
[fabsdk/util] 2019/01/25 12:25:57 UTC - lazyref.(*Reference).setTimerRunning -> DEBU Timer started
[fabsdk/common] 2019/01/25 12:25:57 UTC - retry.(*RetryableInvoker).Invoke -> DEBU ... retry for err [error registering for TxStatus event: no peers to connect to] is NOT warranted after 1 attempt(s).
[fabsdk/util] 2019/01/25 12:25:57 UTC - lazyref.checkTimeStarted -> DEBU Starting timer

After putting some extra logging of our own it looks like the failure happens because the peer discovery service (https://github.com/hyperledger/fabric-sdk-go/blob/master/pkg/client/common/discovery/dynamicdiscovery/chservice.go#L72) doesn't return any peers in its response. The targets seem to be set correctly.

After dumping the GRPC response, we get

(*discovery.Response)(0xc4205cd600)(
results: <
    members: <
        peers_by_org: <
            key: "org1" 
            value: <> 
        > 
    >
> 
)

We also set up a different fabric network on our own with the same chaincode, which works properly and the same dump shows this instead (some parts were redacted):

(*discovery.Response)(0xc42045ed20)(
results: <
    members: <
        peers_by_org: <
            key: "Org1MSP" 
            value: <
                peers: <
                    state_info: <
                        payload:"<redacted>"
                    >
                    membership_info: <payload:"<redacted>" > 
                    identity:"<redacted>" 
                >
                peers: <
                    state_info: <
                        payload:"<redacted>" 
                        signature:"<redacted>" 
                    > 
                    membership_info: <
                        payload:"<redacted>" 
                        signature:"<redacted>" 
                    > 
                    identity:"<redacted>"
                >
            >
        > 
        peers_by_org: <
            key:"Org2MSP"
            value: <
                peers: <
                    state_info:<
                        payload:"<redacted>" 
                        signature:"<redacted>" 
                    > 
                    membership_info: <
                        payload:"<redacted>" 
                    > 
                    identity:"<redacted>" 
                > 
                peers: <
                    state_info: <
                        payload:"<redacted>" 
                        signature:"<redacted>" 
                    > 
                    membership_info: < 
                        payload:"<redacted>" 
                        signature:"<redacted>" 
                    > 
                    identity:"<redacted>" 
                > 
            > 
        > 
    > 
>
)

I am unsure if the issue is in the configuration of the SDK or the IBM Managed fabric network. If it is the IBM network, then it seems that somehow the peers aren't aware that they are members of an organization.

Has anyone seen this behaviour before? I searched the hyperledger official rocket chat for the "no peers to connect to" error, and some results came up, but they seemed to be caused by other reasons, such as the peers being excluded by the SDK, not due to the response to the discovery request.

Top 10 Best Blockchain Programming Language for Blockchain Programmer

Top 10 Best Blockchain Programming Language for Blockchain Programmer

We aim at equipping you with every necessary knowledge of the best programming languages for blockchain and you'll learn more 10 Best Blockchain Programming Language for Programmer: C++, Java, Python, Ruby, Solidity, Go, JavaScript...

We aim at equipping you with every necessary knowledge of the best programming languages for blockchain and you'll learn more 10 Best Blockchain Programming Language for Programmer: C++, Java, Python, Ruby, Solidity, Go, JavaScript...

If you’re a tech-oriented person like me, chances are you’ve wondered at least once about all those latest fusses regarding blockchain and cryptocurrencies. So, what is this blockchain and why’d you be tempted to learn more about it? Blockchain, as the name suggests, is a chain of blocks; connected sequentially using complex cryptographic logic.

This technology was implemented first by Satoshi Nakamoto and was first used in the implementation of the popular BitCoin cryptocurrency. The blockchain technology is being used heavily in the industry, thanks to the high-level of security it provides in business transactions. From corporate firms to industrial banks, blockchain developers are sought everywhere equally. So, wielding this modern-day skill by learning the best blockchain programming language guarantee you an edge over your fellow developers.

Which are the best programming languages for blockchain? Developers are presently utilizing prevalent programming languages like C++ and Java to manufacture custom blockchain programs. What’s more, digital money specialists have made languages like Simplicity and Solidity that are explicitly intended for blockchain improvement.

The worldwide Blockchain market is right now worth an expected $1.2 billion and specialists foresee that it will arrive at a $57 billion valuation by 2025, developing at over 69% every year.

Significant enterprises and investors are teaming up with Blockchain counseling organizations to grow new digital currency innovation, savvy contracts, conveyed records for customary banks, gaming tokens, and inventory network the executives frameworks.

What Is Blockchain?

Customary financial uses a bank as the record and mediator. To move cash to a companion, an individual should initially contact their own bank and request that they move cash to a particular record number. The bank checks the sender’s record for assets, moves those assets to the goal, and records the exchange on the sender’s record. The accepting bank must accomplish something very similar.

In any case, the issue with this customary financial framework is that records are put away inside and are defenseless against hacking and control.

Blockchain disposes of this hazard by putting away all records online in a decentralized, unknown record that can be gotten to by anybody. Blockchain uses squares, or accumulations of information, like spreadsheet lines and segments, to store information. Squares are added to the “chain” in successive request.

In contrast to conventional bank records, which are put away inside, each blockchain client has a total record of the whole blockchain on their PC. This implies they can rapidly discover any exchange that has ever happened in the event that they have the comparing hash code. Since that information is put away freely, it can never be changed or erased — giving clients genuine feelings of serenity and trust in the framework.

Organizations keen on exploiting the blockchain upset should scan for up-and-comers with skill in the accompanying programming languages.

Here are the best programming languages for Blockchain

1. C++

C++ keeps on being one of the most famous programming languages in the tech world and is a prevailing power in the blockchain business also. The article arranged language is ideal for blockchain improvement, since it utilizes similar standards, for example, epitome, deliberation, polymorphism, and information covering up, as blockchain to avoid incidental alters to information.

Engineers additionally prize C++ in view of its memory control abilities. The language helps keep squares secure and deal with an enormous number of asset demands by enabling each system hub to acknowledge or dismiss individual squares.

C++ is additionally utilized broadly by blockchain advancement administrations due to the manner in which it handles parallel undertakings and stringing. The language is equipped for taking care of both parallel and non-parallel assignments, notwithstanding improving single-string execution.

EOS is an awesome case of a blockchain program worked with C++. The open source programming was discharged by Square in 2018 and is intended to process exchanges more rapidly than choices by restricting the product to only 21 square creating hubs. This enables the product to affirm an exchange in under a second and settle it in only two minutes.

2. JavaScript

GitHub as of late positioned JavaScript as the most mainstream language for developers — with a fantastic 95% of sites utilizing it here and there. Be that as it may, JavaScript isn’t just the lord of web advancement; the adaptable programming language is additionally utilized broadly for blockchain improvement.

One reason why blockchain designers prize JavaScript is a direct result of the manner in which it handles offbeat code. This is significant in blockchain, as thousands or even a great many exchanges might be started simultaneously. Offbeat, parallel programming empowers a program to finish numerous activities all the while. Standard, synchronous programming just can’t deal with that volume.

By running numerous activities on the double, offbeat code can improve programming responsiveness and application execution. This empowers blockchain projects to deal with the enormous volume of activities without hindering execution and disappointing clients.

You may also like: How to Build a Blockchain in JavaScript.

3. Java

The only language that can challenge the reign of C++ in the industry is Java, and for good reasons so. Java is in many ways similar to C++ regarding its object-oriented approach and a vast community of third-party applications and platforms. The main reason to use Java as the de-facto blockchain programming language in the industry is, however, its highly-capable portability.

Programs written in Java are portable across any computational device, as they don’t rely on system-specific architecture, instead uses the universal JVM(Java Virtual Machine) for execution. This makes Java one of the best programming languages for blockchain.

4. Python

Python is probably THE most trending programming language you can learn these days!

It's very popular because it's easy to learn and use, runs on all operating systems and allows you to build a broad variety of programs: Be that web applications, desktop applications, utility scripts or using it for data science and machine learning.

You'll do so whilst building your own Blockchain and Cryptocurrency. These are of course also highly trending topics and not a lot of people understand what a Blockchain really is, you'll learn a lot about the core concepts of the Blockchain and you'll see how Python can be used for the many aspects that make up a Blockchain and Cryptocurrency.

You may also like: Building a Blockchain with Python.

5. Solidity

Solidity is a savvy contract and blockchain improvement language that is utilized broadly by Ethereum designers. The area explicit language utilizes a significant number of indistinguishable standards and punctuation from JavaScript to make high-caliber, decentralized applications.

Engineers lean toward the language since it enables them to compose elevated level code for the Ethereum blockchain arrange, the second-most famous blockchain digital currency, which can be assembled into low-level machine code. It additionally enables people to use the Ethereum advanced exchange record to make brilliant agreements between organizations.

The agreement situated language utilizes invariants, preconditions, and post-conditions to streamline the advancement procedure and to make the agreement age process easier for clients.

Solidity is at present accessible on a scope of blockchain stages, including Ethereum, Ethereum Great, Tendermint, and Counterparty. It’s utilized for a scope of utilizations, including business contracts, barters, crowdfunding, and that’s just the beginning.

6. Ruby

Although quite old and tested by the industry, Ruby gained momentum as a blockchain programming language in the last couple of years or so. Ruby, an interpreted high-level language with object-oriented features, much like Python, can be a viable blockchain coding language for uncountable reasons. It offers developers the ability to prototype their vision rapidly using open source third-party APIs and plugins.

The Ruby ecosystem is thriving with loyal contributors since its inception as the de-facto web language starting from the first half of this millennium. It’s especially prevalent within the Asian developers, the most substantial fraction of open source blockchain developers.

7. Simplicity

Simplicity is a fresh out of the plastic new programming language that was discharged in November 2017 and planned explicitly for shrewd agreements and blockchain improvement. The language conceals low-level consistent parts from architects so as to expand efficiency and stay away from engineer interruptions, which is one motivation behind why it is quickly winding up well known in the network.

Like C++, Effortlessness is an item arranged language that uses indistinguishable standards from blockchain to forestall blunders and changes to information. It additionally utilizes Merklized Theoretical Sentence structure Trees to sort out the projects into trees — along these lines taking into account littler exchange sizes and lessening square space prerequisites.

The language’s makers, Blockstream, are as yet extending the language and its abilities. Designers can hope to see Simplicity being utilized in more applications towards mid-2020 once the language is incorporated into Bitcoin and its highlights are concluded.

8. Go

The brainchild of Robert Griesemer, Rob Pike, and Ken Thompson, pioneer of modern programming languages, Go is the best blockchain programming language for building hyper ledger fabric. The statically-typed yet compiled language is on par the performance level needed by a blockchain coding language. Go comes with every advanced feature you’d need when building your first blockchain, namely classes and inheritance, generics, annotations, constructors, and exceptions.

Go offers top-notch concurrency support in blockchain applications, thanks to its smart implementation of channels and interfaces. So, it’s one of the best programming languages for blockchain when it comes to developing a system that is not only efficient but also lightning fast.

9. Rust

The newest blockchain programming language on the block currently, Rust aims at providing open source devs the capability to build fast and efficient blockchain systems. We found Rust to be exceptionally good when it comes to CPU-bound tasks. You can take either a functional approach or an imperative one with Rust for developing your blockchain.

It’s one of the best programming languages for blockchain due to its highly-capable mechanism of handling mutable states. The Rust compiler provides awe-inspiring optimization of your blockchain. The fast, memory safe, and exclusively concurrent nature of this blockchain coding language makes it most suitable for developing real-world blockchains.

10. PHP

Although dimmed not suitable for modern web anymore, PHP still covers the majority of web systems. It can be utilized to build simple to complex blockchain systems as well, thanks to its object-oriented features and a vast active open source community.

If you’re a new programmer looking for getting your hands dirty at blockchain coding, PHP might turn out to be the best option for you. A considerable number of PHP developers will guarantee a ready workforce in case you develop something highly capable and intend on going corporate.

Summary

Blockchain is here to stay. The popular record-keeping technology is what makes cryptocurrency exchanges possible and is widely used by corporations, individuals, and blockchain consulting services for software development.

Developers can easily use popular programming languages like C++ and Java for blockchain development. Alternatively, the community has recently created blockchain-specific languages like Solidity and Simplicity which make cryptocurrency development a smooth process.

Expect to see more original languages spring up over the next several years, as the blockchain market continues to grow rapidly and cryptocurrency begins to be used by ever-larger numbers of people.

Thank for reading!

Deploy and expose chaincode as REST api on amazon managed blockchain hyperledger fabric 1.2

I have configured amazon managed blockchain setup with Hyperledger 1.2. The network is prepared with a single member and a single peer node. Hyperledger Fabric Client setup is with Golang 1.10.3. I have installed, Instantiated, Queried and Invoked mycc chaincode example given in AWS tutorial

Which works perfectly. Complete exercise was done following this link.

I want to deploy and expose the chaincode as REST api. There is a sample project Amazon Managed Blockchain Workshop. They have used RESTful API, running as a Node.js Express application, using the Hyperledger Fabric Client SDK to query and invoke chaincode. I want to run non-profit chaincode example on Hyperledger Fabric Client prepared for AWS managed Blockchain Hyper Ledger 1.2

I have performed below steps:

Here are the steps how am I am running and testing the REST API.

cd ~/non-profit-blockchain/ngo-rest-api
nvm use lts/carbon
node app.js &

If I execute Register/enroll a user request

curl -s -X POST http://localhost:3000/users -H "content-type: application/x-www-form-urlencoded" -d 'username=john&orgName=Org1'

Instead of showing: response:

{"success":true,"secret":"","message":"michael enrolled Successfully"}

It shows below error message.

{"success":false,"message":"failed Error: Missing mspid parameter"}

I have also tried by adding mspid in the request but the error message is still same. What am I missing?

Here are contents of ngo-connection-profile.yaml

channels:
  mychannel:
    orderers:
      - orderer.com
    peers:
      peer1:
        endorsingPeer: true
        chaincodeQuery: true
        ledgerQuery: true
        eventSource: true
<pre><code>
organizations:
  Org1:
    mspid:
    peers:
      - peer1
    certificateAuthorities:
      - ca-org1
orderers:
  orderer.com:
    url: grpcs://orderer.n-XDXDXDXDXDSXDSXDXSDXSDXDSXDSXDS.managedblockchain.us-east-1.amazonaws.com:30001
    grpcOptions:
      ssl-target-name-override: orderer.n-XDXDXDXDXDSXDSXDXSDXSDXDSXDSXDS.managedblockchain.us-east-1.amazonaws.com
    tlsCACerts:
      path: /opt/home/managedblockchain-tls-chain.pem
</pre></code>
peers:
  peer1:
    url: grpcs://nd-NDNDNDNDNDNDNDNDNDNDND.m-AAAAAAAAAAAAAAAAAAAAAAAAA.n-XDXDXDXDXDSXDSXDXSDXSDXDSXDSXDS....
    eventUrl: grpcs://nd-NDNDNDNDNDNDNDNDNDNDND.m-AAAAAAAAAAAAAAAAAAAAAAAAA.n-XDXDXDXDXDSXDSXDXSDXSDXDSXDSXDS.....
    grpcOptions:
      ssl-target-name-override: nd-NDNDNDNDNDNDNDNDNDNDND.m-AAAAAAAAAAAAAAAAAAAAAAAAA.n-XDXDXDXDXDSXDSXDXSDXSDXDSXDSXDS.xxx
    tlsCACerts:
      path: /opt/home/managedblockchain-tls-chain.pem

certificateAuthorities:
ca-org1:
url: https://ca.m-AAAAAAAAAAAAAAAAAAAAAAAAA.n-XDXDXDXDXDSXDSXDXSDXSDXDSXDSXDS....
httpOptions:
verify: false
tlsCACerts:
path: /opt/home/managedblockchain-tls-chain.pem
registrar:
- enrollId: aaaaaaaa
enrollSecret: XXXXXXXXXXX
caName: m-AAAAAAAAAAAAAAAAAAAAAAAAA