IPFS Virtual Meetups, 16 Oct 2020

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From YouTube: Connecting Cosmos SDK Based Blockchain to IPFS with Chung Wu

Description

Chung Wu, from the LikeCoin Foundation, joined us to walk through the latest IPFS Case Study on LikeCoin.

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I'm uh the blockchain developer of litecoin and I'm working on uh our blockchain called litecoin chain, which is a cosmos sdk based blockchain. So my topic is connecting some uh translating cosmetic sdk based blockchain to ipfs, and this talk is.

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This sharing is basically a very quick introduction of uh the case study on uh which is now on the ipfs documents thanks to the ipfs team.

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So if you want more details, you can read the uh read the case study yeah. So let's get started so first, uh let me introduce what is a cosmos. Sdk cosmetic sdk is an sdk uh not developed by us, but by the cosmos team, which is for easily developing application specific blockchains.

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uh It provides many modules that are many blockchains would like to have, for example, defining a token or having governance or having a staking so that the blockchain can run on a proof of stake so uh and then developers can make their own uh modules so that, uh whether we for the functionality of their own blockchain, so that it is called the application specific blockchain which the application is actually the application logic of what the developer wants, and uh here are some chains that is using cosmos, sdk, uh the cosmis hub, which the token is atom uh and also the finance chain.

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uh This one should be quite famous and also iris, snatch and band protocol. These are some famous blockchains using based on the block cosmos sdk, so they have similar interfaces and yeah. They have similarities on their codebase too, and of course, our blockchain litecoin chain is also defined, also developed based on cosmos sdk.

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So you can go to the cosmos website for more uh details on that and for blockchain like on chang. It is a blockchain uh specified on content related functionalities.

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For example, we define the token litecoin, which is uh distributed to distributed content creators in order to reward content, creators and uh currency we're developing a function called iscn, which is a called international standard content number.

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If you go to library, you will read books, you will notice that the books all have isbn international standard book number and we borrow the idea and want to generalize it for all contents on the internet, so that people content creators like video creators or writers who write articles uh can register their content and their content metadata uh on a blockchain and then as uh given, uh given an id for their content, so that others can distribute this. I can recognize it attributes the contents by this id.

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Just like the the isbn that you can search and or identify a book using the number and then, uh if you have, uh we have content metadata storing on chain. Therefore we want to. uh We want it to be uh more uh searchable and accessible from uh everywhere anywhere on the internet.

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So we think that ipfs is a great network for distributing these data so that we think that uh if, uh if we can use ipfs to access the iscn metadata, then that would be a good idea. So I would like to uh we would like to implement this idea through the top ends of ipfs.

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The main implementation of ipfs is go ipfs and it supports plugins.

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Basically, there are two types of plugins: one is datastore which defines how to store or load data, just like, uh for example, which backend of database is are being used by default. It should be level db, which is a very quick database anyway, and another type of plugin is uh ipld plugins, which defines how to interpret data.

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uh Actually, previous speakers have already talked about how they use ipld or expanded.

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So I think you understand that, maybe even more than me, so uh we made two plugins for that uh for our purpose, one is the cosmos d, which is a data store uh for carrying cosmos sdk later originally, we want to embed it into the blockchain so that it can share the database with the block with the blockchain code so that you can directly read the blockchain just like the blockchain database, just like when you're using leveldb level db datastore, it will directly read the leveldb, but we find that in cosmos sdk.

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uh These databases are actually assumed to be a kind of single thread this, so that uh it's not quite possible to share the database instance with the plugin without say breaking the logs or concurrent ss limitations.

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So then we think that uh we need to be more generalized so that so that it is less intrusive and then and uh multiple implementers of the module developers of the cosmos sdk could be uh could be easily in uh easily using our plugins. So we decided to use the dlpc endpoints provided from the cosmos sdk, which is a mechanism that you read from the blockchain.

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So now uh the cosmos, the data store, it will be reading data from cosmos, rpc endpoints, another one is isc and ipld, which, which is an ipld extension for passing ic icm related data stores.

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This is the url for the ibfs plugins for the introduction to ipfs plugins. If you, if you are interested in that.

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So uh basically, this is uh architecture. On the left hand side we have a cosmos, sdk based blockchain, say, for example, like one chain it will have some more drills. Each modules will expose their own rpg endpoints and our module icm module will expose some specific endpoints for uh for the cosmos data for the cosmos data store plug-in.

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Mainly, it exposed three functions for querying if a data exists on uh on the blockchain, the size of the data and also the date and finally, the data itself and then on on the ipfs side or whenever the plugin, the main plugin will be cosmos d, which is the cosmos data store and uh when someone query either from remote or locally uh cid, it will first analyze the cid to see uh to see if the type is.

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Actually the type of the crd is actually a cosmos, sdk or cosmos sdk one, and if so, it will uh process. uh It will process it through the lpc endpoint so that it will carry the it will call the specific endpoints defined by ifcn module or so that so that it will retrieve the cid raw data from the from the blockchain.

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And then, uh if it's not a cid, uh not the data that that is from cosmos sdk, then the request will be simply forwarded to uh to the basic uh level db plug-in and after that. uh If it is a local request, then maybe the user needs to uh wants to pass the ipld data so that so the city data will be passed by the ic and ipld plugin, so that it will be a humor rebuttable one, and then the response is given to the user.

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So, as you can see, it's basically a very simple architecture that actually it does not involve any cosmos related stuff on the on the data store size. So maybe it should be called. I don't know ipfs http datastore or something like that. So our target is to be least intrusive for both cosmos developers and ipfs users.

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So for ipfs users. Ideally they they just need to compile the plugins and then install them on their ipfs clients. Then it could be used. Then it will be usable after some configuration and for cosmis sdk module developers, not only for blockchain.

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They only need to have defined a few extra endpoints for exposing for exposing their contents. Their contents through the rpc endpoints, and also defining their data through the cids, defining the ci deformation of the data, which is the ideal depart.

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Then, then, after that, it would be possible for them to push to make their blocking data accessible through the ipfs network.

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Also, this architecture is simple enough for generalization, for example, if it's not for sdk module cosmos module data, but for the block data or transaction hash, then we could easily implement that in the data store part just curing the endpoint defined by the cosmos sdk themselves and, as I've said, it's also generalized for uh different cosmos, sdk modules, so not just our own blockchain, not just like one change and access it, but also other blockchain other developers can use. This can use this method to make their data accessible through ipfs.

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So this is basically what I want to share about uh uh uh cosmos, uh sdk plugin for ipfs for info accessing cosmos, sdk based blockchain.

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uh As I said before, uh if you, uh if you're interested in that uh you can, you can have a look on the case study which is quite detailed and also if you are interested in litecoin, you can go to like.co for to uh which is our main website and our codebase is in uh on github. You can search litecoin and then you can see our repositories yeah. That's quite a lot of metric.