README
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Chainmetric: Smart Contracts
Overview
Chainmetric Smart Contracts are designed to grand access to blockchain-stored data while implementing such data validation, aggregation, and management functionality.
Being a part of a permissioned blockchain network based on Hyperledger Fabric stack, such Contracts are written in Go and configured to be deployed as Kubernetes services communicating with each other, blockchain peers, and external applications via gRPC protocol and event streaming.
Requirements
- Deployed Chainmetric network (see network deployment procedure) preferably in Kubernetes environment
- Image registry where chaincode docker images will be hosted (Docker Hub account will do)
fabnctlcommand line utility installed on local machine
Contracts reference
Assets contract
Transactions
| Transaction | Arguments | Response | Description |
|---|---|---|---|
| Retrieve | id |
Asset |
Retrieves single record from ledger by a given ID |
| All | - | []Asset |
Retrieves all records from ledger |
| Query | AssetsQuery |
AssetsResponse |
Performs rich query against ledger in search of specific records |
| Upsert | Asset |
id |
Inserts new record into the ledger or updates existing one |
| Transfer | id, holder |
- | Changes holder of the specific asset |
| Remove | Asset |
- | Removes record from the ledger by given ID |
Example
asset, err := network.GetContract("assets").EvaluateTransaction("Retrieve", id)
Devices contract
Transactions
| Transaction | Arguments | Response | Description |
|---|---|---|---|
| Retrieve | id |
Device |
Retrieves single record from ledger by a given ID |
| All | - | []Device |
Retrieves all records from ledger |
| Register | []Device |
id |
Creates and registers new device in the blockchain ledger |
| Update | id, Device |
Device |
Updates device state in ledger with requested properties |
| Unbind | id |
- | Removes record from the ledger by given ID |
| Command | DeviceCommandRequest |
- | Handles execution requests for devices |
| SubmitCommandResults | entryID, CommandResultsSubmit |
- | Updates command log entry in the ledger |
| CommandsLog | deviceID |
DeviceCommandLogEntry |
Retrieves entire commands log from the blockchain ledger |
Example
id, err := network.GetContract("devices").EvaluateTransaction("Register", device)
Requirements contact
Transactions
| Transaction | Arguments | Response | Description |
|---|---|---|---|
| Retrieve | id |
Requirements |
Retrieves single record from ledger by a given ID |
| ForAsset | assetID |
[]Requirements |
Retrieves all requirements from ledger for specific asset |
| ForAssets | assetIDs |
[]Requirements |
Retrieves all requirements from ledger for specific multiply assets |
| Assign | Requiremnts |
id |
Assigns requirements to an asset and stores it on the ledger |
| Revoke | id |
- | Revokes requirements from an asset and removes it from the ledger |
Example
requirements, err := network.GetContract("requirements").EvaluateTransaction("ForAssets", assetsIDs)
Readings contact
Transactions
| Transaction | Arguments | Response | Description |
|---|---|---|---|
| ForAsset | assetID |
MetricReadingsResponse |
Retrieves all records records from ledger for specific asset |
| ForMetric | assetID, metricID |
MetricReadingsResponse |
Retrieves all records records from ledger for specific asset and metric |
| Post | MetricReadings |
id |
Inserts new metric readings record into the ledger |
| BindToEventSocket | assetID, metricID |
eventToken |
Creates event socket subscription ticket for connected party, so that each posted readings record, which satisfies client request for given asset ID and metric, would be send directly to it via event streaming |
| CloseEventSocket | eventToken |
- | Revokes event socket subscription ticket for connected party |
Example
readings, err := network.GetContract("readings").EvaluateTransaction("ForMetric", assetsID, metricID)
Deployment
Chaincodes (alternative to Smart Contracts) in Hyperledger Fabric infrastructure can be deployed both by embedding their source code into the blockchain peers and by deploying them as external services, which is a way more versatile option especially for Kubernetes cluster environment where such Chaincodes can be deployed as a pods.
For chaincodes initial deployment or further updates use deploy cc command as following:
fabnctl deploy cc --arch=arm64 --domain=chainmetric.network --chaincode=assets -C=supply-channel \
-o=org1 -p=peer0 \
-o=org2 -p=peer0 \
-o=org3 -p=peer0 \
--registry=dockerhubuser ./chaincodes
For more detailed instructions please refer to fabnctl documentation.
Roadmap
- Device remote commands over blockchain events (#1)
- Cache layer for storing contracts operational data e.g.
EventSocketSubscriptionTicket(#4) - Devices location management business logic (#2)
- Requirements violation notification
- Requirements violations rule engine
- Transaction for assets changes history retrieving
- Users contract
Wrap up
Chainmetric's Smart Contracts are the accumulation of this project's business logic in the form of distributed, atomically granulated on-chain services, where each is responsible only for its entities, use cases, and transactions handling.
They are exposing access to the data stored on blockchain immutable ledger by publishing their contracts as gRPC remote procedures and continuously emitted event streams.
Other parts of the Chainmetric project, such as embedded sensor-equipped IoT devices and cross-platform mobile application utilizes exposed contacts by remote procedure calling and subscribing to event streams.
License
Licensed under the Apache 2.0.
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