Presentation slides for our first SingularityNET Developer Workshop. To stay tuned with updates about our SingularityNET Developer Program, subscribe to the newsletter via singularitynet.io.

1. Vitaly Bogdanov
SingularityNET
Beta Architecture

2. 2
Agenda
• What is SingularityNET
• MultiPartyEscrow contract
• SingularityNET service
• Multiple service replicas
• SingularityNET clients
• Practice
• Future plans

3. 3
Workshop goals
• Make you familiar with SingularityNET architecture
◦ Payment system
◦ Registry
◦ Client/service interaction
• Demonstrate you how to develop and publish
SingularityNET services:
◦ Learn snet-cli - SingularityNET management tool
◦ Use payment system
◦ Publish service to SingularityNET
◦ Interact with SingularityNET service

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What is
SingularityNET?

5. 5
SingularityNET is an AI platform
Market:
Sell AI service Find AI services by tag,
name, organization
Buy AI service
Decentralized payment
system
Decentralized service
registry
Tools for working with
payments and publishing
services
Platform:

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7. 7
Payment
contract

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What’s wrong
• Overspending:
sender can spent funds before recipient claims payment
• Replay attack:
recipient can pass payment several times
• Each payment requires on-chain operation to transfer funds

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MultiPartyEscrow
code demonstration

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SingularityNET
service

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Registry contract contains
IPFS hash of service metadata:
• Service API
• Service endpoints
• MultiPartyEscrow contract address
• Price per call
• Payment Ethereum address
Organization which published service
Service tags

16. 16
Ethereum and IPFS data

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gRPC call
Details: https://grpc.io
Supported encodings: protobuf or JSON
Metadata fields:
• snet-payment-channel-id
• snet-payment-channel-nonce
• snet-payment-channel-amount
• snet-payment-channel-signature-bin
• snet-payment-type = “escrow”

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Client/service interaction

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Service protocols supported
Supported protocols:
•service: gRPC + protobuf => client: gRPC + protobuf
•service: JSON RPC => client: gRPC + JSON
•service: command line => client: gRPC + JSON
Command line service:
•receives method name as first command line parameter
•receives data sent by client from STDIN
•returns data to client via STDOUT

20. 20
Payment validation
• message = mpeContractAddress + payment.channelId + payment.nonce +
payment.amount
• signer = signer(message, payment.signature)
• payment.nonce == channel.nonce
• payment.signer == channel.signer
• currentBlock + metadata.paymentExpirationThreshold < channel.expiration
• payment.amount <= channel.value
• payment.amount - channel.authorizedAmount == metadata.price

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Service claim funds

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Client gets channel state

23. 23
Payment is not collected after error

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Daemon error codes
•Unauthenticated - incorrect payment
•IncorrectNonce (custom code) - payment nonce is incorrect; possible reason: service
provider claimed funds and incremented nonce
•FailedPrecondition - another call is in progress
•InvalidArgument - payment metadata cannot be parsed correctly
•Invalid - internal daemon error - usually means incorrect setup or code error

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Multiple
service
replicas

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Multiple replicas setup

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Sharing channel state between replicas

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ETCD
Link:
https://github.com/etcd-io/etcd
NoSQL Key-value storage
Strong consistency
Tolerant to network split
More than half nodes unavaiable =>
service unavailable

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Internal and external etcd cluster

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Colocated replicas

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Channel is bound to group

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SingularityNET
Clients

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snet-cli commands
•identity
to manage Ethereum identities
•network -
to switch between Ethereum networks
•contract -
to call Ethereum contracts
•organization -
managing organizations
•client -
to interact with SingularityNet services
•service -
to publish and update services

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snet-cli commands
snet identity:
•Create, delete, switch identity
•Supports hardware wallets, rpc endpoint, mnemonics, private key
snet network:
•Switching between mainnet and testnets
snet contracts:
•Call SingularityNet contract methods
•Auto-generated from contracts ABI

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snet-cli commands
snet organization:
Create, delete, list, get organization info, list services
snet service:
Prepare metadata, publish or update service metadata and API
snet client:
Interact with MultiPartyEscrow and service: deposit, open channel, check balance,
get channel state from daemon, call daemon method

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Steps to call a service
1. Get service metadata IPFS hash from Registry
2. Download service metadata from IPFS
3. Get list of endpoints, payment address and price from service metadata JSON
4. Open payment channel using MultiPartyEscrow contract
5. Correctly form payment metadata for gRPC call
6. Make a gRPC call
7. If endpoint is not available switch to another endpoint in same group

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SingularityNet SDK
•Call service providing payment wallet only
•Manipulating payment channels
•Ensure client and service use same API and MultiPartyEscrow contract
instance
•Storing payment channel state locally

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Compiled and interpreted languages

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Practice

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Future
plans

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Resources
SingularityNET Homepage
singularitynet.io
SingularityNET documentation wiki
github.com/singnet/wiki

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