Hyperledger Foundation Meetups, 2 Feb 2021

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From YouTube: Why DAML: Using a high level functional language to create smart contracts

Description

A virtual meetup hosted by Hyperledger Boston. In this session Anthony Lusardi from Digital Asset will also be showing off a live demonstration of a beer IOU tracker in 30 lines of DAML, and a full end to end deployment of a DAML application on Fabric that you can follow along with in your browser.

More Daml resources are at: https://bit.ly/trydaml

More about the event is at: https://www.meetup.com/Hyperledger-Boston/events/275086009/

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Hyperledger – Open Source Blockchain Technologies

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A

um Markup language for um smart contracts uh on a variety of different frameworks, including hyperledger fabric. So another meeting is just wrapping up and we'll get started in a minute or two. I'm gonna wait for some more people to join.

B

Awesome thanks jim and yeah. Let's give it a few more minutes, also uh demo being all caps has um proven to be very misleading.

B

Dowell actually used to be a different language, which was a markup language of sorts, but demo today is actually a functional programming language based on haskell and we've actually recently dropped the cap, so I'll actually hop on video, and you can see. I have an old t-shirt where damil is still all caps, and uh this is this is no longer on brand. I, I probably will be chastised for wearing this okay, fair.

A

Enough I'll just put a comment in the chat right now, so the question is yeah before we even start um we'll wait for more people to join, but um would you categorize demos I'll call it a dsl, a domain-specific language built on top of haskell that basically compiles down to that as a runtime.

B

uh Yes, somewhat it's built with haskell, so it compiles down to an intermediate language called demo lf, uh but it's very haskell like and we actually use the ghc compiler on the back end. So yeah. It is kind of a dsl for these things, though,.

C

Yeah yeah cool and jim and anthony- I don't want to interrupt, but just to let you know the live streaming is now up. I put a link to that in the chat and again, as you know, there's also a chat on the live stream page. So when you get to the q, a you'll probably just want to look at both places and I need to jump for another call. But jim your set is the co-host I think, you're all good. That's it great awesome. Yeah bye.

B

C

A

All right, let me grab the live stream right here, so yeah. Anything that makes um blockchain easier to build and support is always interesting. So we have a number of people listening here.

B

And everybody can see my screen right, uh yeah.

A

Okay, so anthony is your company based out of boston.

B

uh No we're based, I guess, out of new york and zurich, are where our two largest offices are.

A

B

But I know boston. Well, I've been up there. Many many.

A

More than we do today.

B

For sure that's surprising, but yeah we had so much snow, it's still going. Actually it's quite incredible.

B

A

B

I'll give it.

A

Another minute, then, we'll get started so there's certainly a lot of interest in space. The other thing that's a bit of a challenge. I assume, on your end, is the blockchain architectures underneath are not stable.

A

Much like I guess, yosemite or yellowstone in that area. I would say that the architectures change frequently, so it must create some challenges. On your end for the mapping there.

B

uh Yeah it does and it doesn't create challenges for me, but it creates challenges for some of our engineers um but yeah in general. There's there's definite change and uh it's not too. It's not been too too bad, though, uh for some of the upgrades I mean I haven't been too uh intrinsically linked to them, but yeah. It is something that sometimes versions you know, might fall behind by a release or so uh for what demo will support? Just because you know you have to play catch up.

B

Hopefully, as time goes on we'll be able to, you know, establish uh longer more solid relationships with some of the larger. uh You know blockchain developers and then then get up get a little better on that, but yeah there's there's definitely a bit of a delay.

A

Yeah, I will say the open source ones, at least for the most part, do a decent job of showing you potentially what's coming. If you're the guy, who has to map you know demo to fabric or ethereum or one of those, they usually have a back log of rfcs that are prioritized to give you some clue of the challenges that are coming. Your way exactly well.

A

So with that, let me just stop and reintroduce our meeting today um we'll get started um so we're going to talk about a demo, uh a new smart contract language that runs on a variety of different um blockchain platforms, um and we have anthony desarti today uh to talk about it.

A

Who has a long background, both in bitcoin and smart contracts and uh has been working in the space for about eight years now and he's the developer advocate for digital asset, and so uh with that anthony I'll turn it over to you, and you can give us some uh detail on what demo is all about and how we can get started.

B

Awesome thanks jim uh yeah. I've been in this space for a while. First though I wanted to say you know thank you, jim and david, who had to hop off for another thing, um but thank you both very much for helping put this together. I think it's really great that you've been so open to giving us a platform to talk a bit about this language that we produce, um which is really really great. So thank you very much uh and yeah to introduce myself uh I've, probably yeah.

B

I've been interested in this space for probably about eight years or so now. Now that we're in 2021 um I've been like more because I had a passing interest for a few years and then I started developing a much stronger interest as time went on so probably around like 2015 2016 is really like when I first really got interested in the space and got it really interested in things like ethereum and bitcoin.

B

um I got interested in ethereum because I thought smart contracts were really cool. Actually back then I didn't understand bitcoin's monetary proposition, so that wasn't that important to me. So I was really interested in smart contracts and I think smart contracts themselves actually, while bitcoin really established itself, smart contracts themselves uh are really still emerging and are really exciting space.

B

So I'm I'm actually really happy to be working on them, full-time and yeah, so that that's me uh now, I'm at digital asset working on an open source, smart contract, language called daimle, and essentially what demo does and I'll talk about this more as we go on. But it is a language that has an intermediate runtime that essentially we use the underlying ledgers like fabric sawtooth and others to commit data and to give us our consensus over our application and its state.

B

uh But it doesn't actually, you know embed itself into where it's actually executing within the same fabric node, for example, in the same way that chain code would so that's a slight difference, but I'll actually discuss that a little bit more later. Also, we are giving away some t-shirts today, so the first five people to ask a question uh will get a t-shirt if you want one.

B

The designs, actually that we have up are even are a bit nicer than um what I have on, not to say that this t-shirt's, not nice, but our newer t-shirts are very pretty and you could just see them all over here and yeah. I actually have this one too, but it's in the wash and anyway that's what we're we're giving away. So, if you're interested at all go ahead and check that out, um they're they're really go.

A

B

Ask a question: sorry. I was doing too many things at once. What I was saying anyway, uh so basically the first question you could have for smart contracts and really programming languages in general. Is you know? Don't we already have all the languages we need, um and my answer would be we don't and what we actually have are a lot of languages. That kind of do the same thing in different ways.

B

So you know, for example, if I were to write in python, I would basically be writing uh not 100 similar, but about 80 similar to, if I were writing in c sharp other than you know, some things about how I actually structure my classes and those types of things, but really like in in general, we're just doing we're doing imperative languages and we're uh doing class-based languages, and so demo is trying to do this in a bit of a different way, and so, even when it comes to you know, languages for blockchains and distributed ledgers, we're finding that they behave like their contemporaries and that they also manage very low level concerns.

B

So what I mean by the first part here is that, when you're behaving like your contemporaries, we've seen things like, for example, ethereum several years ago, had a reentrancy attack on one of their largest smart contracts, and that was because essentially the way a blockchain actually works and commits data was incongruous with the way that solidity code really was structured and in such way that you can actually execute other code inside loops and you're.

B

Not getting the guarantee that previous things that you thought terminated have actually terminated, and so that was a very interesting learning to have and we're actually getting a lot more of those when we try to fit these very imperative languages, sometimes to the structure of no. We want to commit a block of transactions, and we want those to be final and, along with that, we're also finding that we're having our languages deal with very low level concerns almost to the level of your programming, the database directly and when it comes to current modern languages.

B

We don't really do that in general, outside of of blockchains and distributed ledgers. We actually have a good deal of abstractions that make our life a lot easier there. We have a question here uh from sam.

B

Is it a common runtime being leveraged across platforms, or are you having to write an implementation of the runtime miller for each chain? Also? Is this runtime code formally verified for mathematically? Okay?

B

uh For the first part, the question is basically: do we need a different implementation of the runtime for each chain in general in somewhat yes- and someone know we do have, uh for example, dem along kv is kind of for when we're doing key value stores that would be the base and then we they would essentially make it talk to each and every one of those and then, in other cases uh yeah.

B

It is completely custom, but there are some efficiencies there, but essentially yeah each time um a runtime has to be custom made to the type of architecture it's running on so there's a custom runtime for fabric there's a custom runtime for sawtooth uh there'll, be a custom runtime for besu and also is it uh formally verified? I don't know if the entire thing is. I know we have um rather large test suites, obviously, but as far as formal verification, I don't believe we're fully formally verified, uh but that's actually a very interesting question.

B

So, um if you wanted to, you could always ask on our forum and say: um what's this: that is a demo drivers which demo drivers by the way is what we call runtimes.

B

C

With respect to formal verification.

B

We could just ask that in questions.

C

Verification tag we did not, you should promo verification.

B

No, we can ask if.

B

Anything and we'll probably get an answer in a little bit, we're also a fairly active forum too. So you know if you ever have a question like that. I can't answer it. I'm sorry, but I'm sure somebody will be able to- and that is a great great question though, and so yes, just to go back demo now really differs in what it does uh and demo basically is a portable language for dlts, and so that gives us quite a lot of neat features.

B

And so, when we think about this, we can think about some of the things that being this style of language and how we actually structure demo. You know we can get very concise epic applications in terms of the code written for them.

B

uh We actually have a couple blog posts where we compare code written in one language versus another for demo and others, and what we find and like what anybody will tell you when they're working in functional programming languages, like haskell, for example, is that they get a lot of these cool efficiencies and that they can write a lot less code, um and so that carries over to us as well, which I think is great, because we're really, when we're doing it and I'll show you some actual code. uh We're talking about use case.

B

We're sorry not using we're talking about business logic, uh and we only really write the business logic and the runtime figures out everything else for us in terms of data persistence and then the ledgers also figure out the actual transporting of that data and uh consensus for us, and then you know it's very efficient because we get a good deal of security and privacy without writing additional code. I'll actually explain that kind of how damol has these separation of concerns and kind of similar to how unix has read, write and execute operations.

B

Demo has signatories observers and choices which kind of map one to one to those respectively.

B

uh It's also, you know, designed for multi-party systems where you're dealing with multiple people, and so like all these things are expressed as uh intrinsic parts of demo, and it becomes very portable in that we end up with demo applications that when we write it right at once, uh we can deploy it anywhere across platforms and also we're working on making these things much more interoperable.

B

So right now, obviously, demo applications can be interoperable with each other within the same network, and we also have a technology called canton that will allow for intercommunication between these different networks. So if you have a fabric, node and a sawtooth node, you want the same application to deploy to both of them and talk across them. That's something that we're working on it's actually at canton.io.

B

I'm not going to talk really about canton right now, it's still very much in development, but it is there and you can actually try it out too, but anyway, that's that.

B

And so, at a high level, we can say that you know demo is a consistent language for distributed and relational databases, especially if you're a developer. That's probably what's most important to you, but it also reduces complexity when developing your distributed application. So if you're a developer or project manager, that's probably something that's really important. Also, you know when you're writing your demo application.

B

You don't have to think too much about what your backup infrastructure is going to be. Yet you just have to make sure it's going to be at least one of the things that uh demo involved that um it's going to be one of the things that uh demo supports and there's another question from sam does canton involve state channels that I'm not sure how canton implements it, but that's a that's a really great question for the forum.

B

um I I'll definitely also make sure to ask that once once this is over, uh because that that's a good question no worries. I I'm fine talking about it sam, uh if, if anybody has any questions about tamil or these associated things, even if it is canton, uh you know feel free to to ask them whenever you want, um but anyway, this ultimately translates to. We get a lot faster, more accurate development of distributed applications. So no matter who you are and you especially, if you're a decision maker.

B

This is really important because you don't have to worry about. Oh this infrastructure wasn't right for me.

B

I want to switch uh to this other cool technology, but I can't now I have to re-implement my entire application, so you can really avoid that and we actually see too a lot of people really love demo for prototyping and then can go ahead and take that that prototype and just expand upon it because it is written in such a functional language and everything is so composable and the concerns are so explicit that it's really like you don't have to discard your prototype because, truly as in any good functional programming, language, there's generally one or two correct ways to write an application and every other way is is hopefully impossible.

B

Is how it's how we try to do that. But anyway, let's talk a bit now about kind of what apple looks like I could, even you know, show you it in visual studio code. Obviously we have a. We have a light ide and development toolkit and command line assistant along with this too, uh but just since we have it on the slide. Here we have our two templates uh they're called beer proposal and beer iou, and this is also where the talk gets.

B

A little more technical- um and you can kind of think, though, of these templates kind of as if they were classes within a with within an imperative, class-based object-oriented language, uh and essentially these templates. When you use them, they get instantiated as something we call contracts, which is the actual instance of it.

B

uh So and the other way you can think of these, which is fun because demo does so much of this work, for you is that you can think of beer proposal and beer iou as actual tables within a sql database, or uh just you know, for thinking about it. In that way,.

C

B

If everybody can just mute themselves.

B

Thank you and anyway, um what I was saying there is that this is another cool thing is that damo's concerns are such that not only do we get a class here with this declaration, no, no worries for the noise, it's okay, but we also get a description of what our table is going to look like or really what our data structure is going to. Look like I'm going to talk about it in terms of sql, but I don't actually mean sql sql. All the time. uh Also sam mentioned that uh my slide mentioned relational databases.

B

This down will work with uh other databases. um It works with relational databases such that it works with both postgresql postgres right now, and it will eventually work with oracle db.

B

It doesn't work with any rdf or graphql or other databases right now, so it's really the same equals and the blockchain slash distributed lectures of the world, but yeah that's a great question anyway. um So we can think of the these declarations here now, with width are basically kind of like rows in our tables um or columns in our tables and then we'll populate them with contracts that are rows uh to break that down into the sql metaphor, and then we have some fun fun things here.

B

Is that, uh because we've been so explicit now, we can also be explicit not only about what data we're storing, but who has rights over that data, so we have signatories to a contract which they should basically mean. This is the person that has instantiated the contract. uh That's that basically has the final. Has the authority to write the contract?

B

So obviously uh you can instantiate this template as many times as you want into separate contracts, but each and every one is going to have a set of signatories, and in this case our signatory is going to be our beer.giver, which comes off of our beer iu template here.

B

The observer you can think of this kind of as the read permission who can see the contract is the recipient, so they can see that proposal has been made to them, while the giver can actually write and instantiate the proposal, and then we have some guarantees and then we have choices which are essentially like execution permissions. We basically are saying for each of these choices.

B

We can have various controllers that can actually exercise the choice, so the recipient can actually choose to go ahead and accept the beer, in which case they will create it and instantiate a beer iou contract between the giver and recipient or they can choose to reject the beer or the beer giver.

B

If the proposal hasn't been accepted yet can actually go ahead and cancel it, and one very nice thing about all this is that these are all structured as utxos, uh similar to as it is on bitcoin, where, when you have a beer proposal contract out there in the world, you can only use it once and when you use it, it gets uh essentially archived and can't be used more than once.

B

So everything stays nice and atomic, and so that means that we can't end up in a situation where the giver and the recipient have a race condition where, maybe I is the giver and sam is the recipient, are trying to cancel and accept the beer respectively at the same exact time, and we end up in a con conflicting state, damo's, uh drunk uh runtime driver is basically guarantee that this isn't going to happen, and the other nice thing about this is that with the signatories and observers we can create obligations between parties that uh we haven't explicitly signed off on.

B

So what you might notice here is that, uh in order to actually make this beer iou template, we need a sam here, for example, in the accept beer to sign off on actually accepting it, because I can't make an obligation that says I owe sam abeer uh via the spear iou on the right-hand side, without sam actually agreeing to it and the way that's enforced. There is uh that um basically uh authority and and signatures on these contracts, probably propagate downwards, to child contracts.

B

So what happens here is I put my signature on a proposal and then sam as the recipient, can go ahead and accept the proposal and put his signature on it and then once sam's signature is on it. uh We can go ahead and actually instantiate the beer iu contract, because now we will have signatures from both the giver and recipient sam says thanks for the beer. What do I owe you nothing? The questions?

B

The questions themselves were were more than worth owing the beer and very funny and yeah, so that's kind of how this works as the contracts and then I'm actually going to deploy this application uh very soon. But we're essentially talking about quite a lot of things here that we get out of the this, this small bit of code uh for free. So we get our data persistence.

B

We get consensus uh by connecting it to a ledger. We get a json api that we can talk over and it's it's a common api. uh That's very similar, no matter what type of application we're working on. uh We get separation of concerns and you know we get all these very, very fun things and with all that, we're actually powering a ui that looks like every other ui out there.

B

We actually have uh react, um react libraries to interact with uh our application uh with our back-ends code and we have a code gen that generates javascript and java. That also interacts with the backend's code, such that it basically creates classes and other niceties that uh directly from the code we've written here, so that we can just import it into our java code and actually show that right now, um because it's fun so here's beer.damo- and we have this code here and what will happen is and I'll actually walk through.

B

The steps in a moment is we can actually go ahead and import all of our uh contracts and templates here as javascript code, and we can actually go ahead and use it in such a way down here. So this is all this class basically comes from auto generated code, which is very nice. It makes it very easy to consumer applications, but I.

C

B

Kind of jumping ahead of myself so.

C

B

We're going to hop over to our toy production app and in much the same way that I will send up here, I'm going to actually show uh how we can do this now at how we can actually deploy this application, where we basically pass around ious between each other for beers, and so the first thing I would want to do is I would want to start up a little network where I can get these things going, and so I'm going to head over to our download fabric repository. This is all open source.

B

I think it's under apache 2 and I'm going to go ahead and download and install demo. I mean demalon fabric, which is basically the demo driver for talking to our demo ledger. The one thing, though, I'm going to skip here is I'm going to skip the actual cloning and installing some of the hype fabric tools, because that'll take a few moments, so some of this I have already done, but anyway, our first step is actually going to be to navigate into this directory. Here.

B

And then, as we see here, we're going to run our gen dot, sh and restart fabric.sh commands and the first one is just going to generate our fabric config file. Obviously, if you have your own fabric network, you can also set this up to talk all over your own network, but this is basically for nice and easy development and then we're gonna go ahead and start up our fabric network, so we're starting up our fabric network here and it's up and running beautiful now. Next, we need to go ahead and deploy our download application.

B

So I'm going to head over to the deployment guide. The deployment guide by the way here is actually written for another project called create data mlap, which is another example. We have that's available in our docs and while it's specifically for that application, it's very generalizable to what we're doing here. So normally we would go ahead and build our application, but I'll build that separately.

B

We've already cloned our demo on fabric and got that up and running, and so now what we're going to do is we're going to start up our download driver this case with this command sbt and that's just going to take a moment to start up. So while that's starting up I'm going to go ahead and actually build my application so that we can be ready for that. So I'm going to go ahead over to my.

C

Repository, oh.

B

And right over here we're gonna, see building it is fairly easy. We basically need two commands and then we can start our ui after that too.

B

So to build our our application, we're going to go ahead and run demo build and that's going to compile all of our code from demo into an intermediary language called mlf. But you don't need to worry about that, but it's actually very similar in respects to java, in that it's compiled all the code and everything that is necessary to run the application is zipped up into this file.

B

That's called the dar and that's very much akin to a jar file in java, for example, that it's all one self-contained uh set of set of codes and then we're gonna go ahead and run our demo code. Gen and, like I talked about before that's going to go ahead and generate nice little classes that we can use within our javascript application uh to interact with our contracts without having to be so specific about it.

B

And you know if they update and we change them, then we can just run codegen again and that'll uh properly reflect the current state of our contracts and now going to head back and let's see if our demo off fabric is a demo on fabric driver is up, and it is, we can see right here. It's talking to a ledger called fabric-ledger and it's on port 6865., so perfect.

B

Now what we're going to do is take that code we compiled and actually go ahead and deploy it to that uh to that port, because that's where our dental driver is running and we'll see right here that the all the files are being uploaded and written to our actual ledger- and we can actually see two over here- is that the data has is being written and recorded in fabric itself, so that handles all that for us and is very very nice and now that our code's actually running, uh we can go ahead and expose our json api.

B

So again we haven't written any code for our json api, we're just going to go ahead and point it at that same port, 6865 and then I'll serve up my json api on 7575, where our ui will talk to it. So this will take just a moment and now it's up and running and now I'm going to head over and build the ui. So if I go back to my opier, the readme says all I have to do really is yarn.

B

Install I've done that already just to save us a few moments from uh having to install all the node.js requirements and go ahead and yarn serve, and that's just going to take a moment and it will spin up uh our front ends.

B

So now we start it up, I'm gonna go ahead and just come come here and log in I'll log in as one of our test, users alice and I'm gonna offer a beer to bob, and you can see it's been offered. There's no trickery here. If we go back, uh you can see right here that you know we've I'm missing a header, but it's complaining because it's actually receiving data. Then we can see right here a few seconds ago.

B

The data was actually ready to fabric and fabric actually went ahead and recorded it, and so that's great we're going to have alice, also offer a beer to carol and that's kind of where we're going to see that the separation of concerns. uh So if I go ahead and log in as bob.

B

Now I haven't on the back end written any code that basically makes sure that bob can't see carol's uh transactions or that they're separate and in the front end I'm also not querying in a way that is um going is going to be very cautious about what proposals I'm getting back, I'm literally just going ahead and querying and saying I'm bob.

B

I want all the proposals and the ledger goes ahead and says: okay, bob, here's, your proposals um and bob doesn't know anything about carol's because they haven't been disclosed to him and so bob can actually go ahead uh and accept the offer and then, when and that'll you know go ahead and exercise as well writing to both writing to the through the json api to the demo driver and finally to fabric, and then once you know, alice and bob have agreed that the that alice's once bob agrees, that alice has given him the beer that he owes.

B

B

He can go ahead and mark that as received and all the while uh carol's is unchanged and private to her actually well between her and alice, and you know, carol can also go ahead and say, reject and what that'll do is it'll exercise the proposal um and then, by default every time uh a choice is exercised on any sort of contract.

B

It archives it. So there's nothing else to do on it, and then it goes away and so yeah that's pretty much demo. Actually what the other fun thing I can do now is, I can take the same application and with just a very minor tweak to my ui. I can just deploy it elsewhere. So what I'm going to go ahead and do?

B

Is I'm going to take down all my docker containers and I'm actually going to make sure I stop.

C

B

My darker containers, too,.

C

C

B

Really bad at running soccer.

C

What's the commands for that?

C

C

B

There we go stopped all my docker containers and I'm going to delete them as well. So now, what I'm going to do, though, is I'm going to head over.

B

B

Bluetooth and I'm going to deploy the same exact application there.

B

Obviously I've taken it down from the other place, so there's no need for data persistence there and yeah. Let's go just try this out all right. So, let's head over to.

C

B

Perfect so now we're going to head over to demo on sawtooth.

B

And we're going to follow basically similar steps, though this one runs slightly differently and that when I start it it'll actually go ahead and start up both the sawtooth instance and uh the demo driver in one go up. I need to actually build something. First,.

C

So, let's build it: okay,.

B

This little isolation id and then we're going to just run bin slash, build.sh and that'll actually take a moment. So if anybody has any questions now that that'd be fine to ask just because this is going to take a moment to build, I had it actually realized. I didn't have it built, but while we're doing that, I can actually go ahead and show you through some of the things you can do.

C

B

So actually, let's head to discussion.com start, and this is actually the same link as over here bitly slash, try demo, so you can go ahead and check that out.

C

B

And what you can do, basically, obviously, you can go ahead and try out and install the demo connect sdk toolkit.

B

uh We also have demo.com learn, though, which I think is a really great way to kind of just dip your toes into demo, because everything here are basically self-guided documents where you can go ahead and try things out yourself.

B

So if we wanted to actually not do it locally, I could actually run through deploying download sawtooth in my browser here and start it up and deploy it over on a server that I don't have to worry about.

B

So you can do that all within your browser, you can learn all sorts of concepts as well, so we have a large variety of tutorials that basically go into fundamental demo concepts uh that I think are very useful and obviously necessary for when you're, when you're working with that with demo.

B

So there's that uh there's docs.demo.com over here in getting started or actually under writing demo an introduction to demo. This is basically the book on demo that uh bernhard, a co-worker of mine has written, and it's absolutely great for learning the language in depth to to really know every all the basics you need to know about tamil really. Actually it's a bit more in depth with this basics, though,.

C

B

uh Then we have disqus.demo.com, that's of course our forum, where, if you have any questions, you know, if you spent more than five or ten minutes uh trying to figure something out, you can go ahead and post your questions there. Then we have our certification, which, as you might see over here, there is a 100 off demo associate exam code as long as you enter in hl, boston and basically for the first 10 people that go ahead and and sign up for it, you don't need to take it right away.

B

You can go ahead and register it and take it later, uh but you can go to devil.com certification and click on purchase the exam except you won't have to pay for it, which is beautiful, everybody likes stuff for free and yeah, then. Lastly, we also on the business side. Obviously, if you're, if you're more in on the decision making side of your organization, you know we have digitalasset.com services and the entire digital asset website, where you can learn more about uh the productized and solution options that that we offer as a company in general.

B

I won't talk too much about that right now, since we're talking about download itself here. So let's go and see: oh we're still downloading and compiling so that'll take just another minute and yeah. That's mostly what demo is, but I just want to prove to you that that we can write this code once and deploy it anywhere, and actually, while doing that, I will update this one little thing where later our application will want to make sure it's talking to the right ledger. Id and it'll get upset if we don't narrow out. So, let's.

C

A

So anthony two quick questions, while we're waiting, I guess.

A

We have pii information um a lot of times about me. You know whatever it is whatever we're tracking me in a golf tournament, and you don't want all my personal information out on the ledger. How does you can tell us how demo would handle that.

B

uh Yes, so in vanilla demo, the way you would handle that is making sure that, when you're structuring your applications that you have kind of a separation of concerns.

C

B

Bernhardt actually wrote something on this forum without attachments and kind of how to do that. So I can actually go ahead and share that link in the chat. But basically there are very good reasons like you mentioned, especially pii, not to store all that data on ledger. So there are ways to to work around that with vanilla, damo and then the other option, of course, is uh canton, will eventually have pruning. So that would be another option.

B

You have such that you can delete data off of uh off of the ledger whenever needed, and so those are the the two options that that you have right now. Obviously canton abstracts that that part away from you a bit it makes it a bit easier to deal with.

B

So that's one approach, but if you're dealing with vanilla dabble you have to give you know some thought to what data you're, storing and where- and I think, that's actually a good thing, um obviously slightly more cumbersome than we would like and which is why I'm very excited for canton's approach, but it's very good to actually uh think about what pii are storing. Where and when and who can see it um and by forcing you to think about it, it may help. You know long term make people uh more cautious and better about storing pis.

B

But that's that's a great question.

B

And yeah so now, download sawtooth is all compiled and should be ready to go. So I'm going to head up the turning tab.

C

At the directory.

C

Run.Sage start.

B

And so this is going to start up simultaneously, so slightly different from fabric. Like I mentioned, it'll start up the the sawtooth node itself and, at the same time it's also starting up the demo driver that will talk to it. So you'll see that in a moment, it'll say rpc is what they were, calling it internally and that'll.

C

Get started up in just a moment.

B

And then really once we have that up, though uh we're basically going to work through the same exact type of deployment. You'll actually see, do you have a deployment?

B

No, we don't um it's going to basically be the same exact deployment steps after we get the demo driver up, and so rpc is up except this time we're running on port 9000. Our our ledger. Id is called test, since this is a test network, so we're going to go ahead and run demo build again. Actually we don't need to run download build again. um We don't need to run download code gen again. We can just actually go ahead and demo deploy.

B

So I'm going to skip those two steps and run my same demo to pull your command except this time, I'm just going to deploy support 9000, which our sawtooth instance is running.

B

On and then I'm going to go ahead.

B

My left report here as 9000 to start the json api. Again, none of the code has really changed. Oh demo, deploy actually does recompile, but that binary should basically be identical to the previous one. So there was no special things we had to do there and then go ahead and yarn serve and that'll start up our ui again.

C

B

C

And connect to it.

B

Again, go ahead and log in as alice and alice can go ahead and offer boba beer again the first time it does this. It actually takes a moment and that's just because it has kind of a just some time, compilot compilation going on, uh and then it speeds up after that and as you can see you know, we've received some data through our json api and it's gone through uh both the the download driver download pc over here and then getting stored in the in the in blocks itself on sawtooth and yeah.

B

That's that's basically, example and how it works, and so we have a few minutes left. So if anybody else has any questions uh feel free to ask, but otherwise yeah. This has been a great presentation and thank you, sam for the very and jim, for the the very great questions they were awesome.

A

Yeah, if you want to ask a question, please just unmute yourself.

A

uh All right so I'll take the gap that I have on nobody asking questions, I'm unmuted you're now on deck. One of the challenges we talked about. You've got multiple platforms here that you're right into and the one thing in fabric I'll give you an example of a feature that I don't know how you map to. It is in a fabric network, if it's I'll say, suppliers and customers kind of a thing. You know vendor relationships um across a network.

A

You have 10 companies and summer vendors to others that are in a sense of purchasing from these vendors. In that world in fabric we can say: okay, vendor a is going to sell to company b and they're going to have a contract. Well, the contract does go out of the networking fabric, but we would want the terms of the contract to be quote private between them, so the rate that they're selling and all that would be private- it wouldn't be shared, even though the contract itself winds up getting distributed across the network.

A

The terms of that contract are private. Between a and b. How does damol support a feature like that.

B

Yeah the way demo does that, and obviously some some ledgers are more gossipy than others, uh but the way damo does that is it only discloses the information that it needs that needs to be disclosed to the to the nodes that need to know that information. So, for example, if bob is running a node and carol is running a node and uh bob and alice have a contract.

B

Alice's node is only going to send the data about what they're doing to bob and and simultaneously alice's node is only going to send the data about what they're doing to carol for the contracts involving capital, so that's kind of how it deals with that is. It doesn't share data where it doesn't need to. It only shares data on a need to know basis.

A

Excellent: okay, thanks.

A

Okay, uh anyone else have other questions. um You know once again, it was great presentation. On my end, I think uh it's interesting because it does have potentially a lot of applicability.

A

It sounds like you got the resources on the site if we go there um to easily start learning this with the guides, um you know the support community channel there to answer questions. That's a upload, a good set of resources, and then this thing where, if anybody's interested uh to get a free certification, is uh unusual.

C

uh Folks, uh are you able to hear me yes, yeah yeah, my name is mayapan. um I joined uh very late, but uh I got the gist of a great presentation. um I have.

B

C

um This just because the lack of knowledge just bear with me is there a way from sought to to integrate uh any cryptocurrency um into sawtooth or ledger hyperledger any cryptocurrency can that be integrated into the transactions.

B

um Obviously, you can store any type of data or state. You want on a sawtooth or fabric ledger or any ledger. um It really depends on like what what you mean by that, I think in general, when we think of things like sawtooth and fabric, we think of private distributed ledgers that uh are only concerned with certain parties and have some sort of ultimately permissioned type of architecture.

B

Even if part of that is, you know, anybody gets the read permission, but uh when you think of cryptocurrencies in general, like, for example, bitcoin, you think of those as much more public types of blockchains, where uh really really something like really public blockchains would be better suited to those things. I I would think in my in my opinion,.

C

Yeah so um let's say I'm making a purchase of uh a pound of cotton yarn from from uh from a supplier right, so I'm willing to it's a hypothetical thing that I'm really trying to do. I'm calling this. uh We are calling this product textiles. So we are. We are trying to ponder on that.

C

So um so, if I, uh if I, if I, when I make the purchase instead of making a payment uh using dollars, can I and I can capture all the letter of credit and all the documentation associated with it in in sato? What make my payment through through the exchanges and can I reflect that? uh Just that amount into into to where my contacts are? Can we make a bridge between between the two between by getting the data from the exchange from my wallet.

B

uh Yes and so now yeah, I understand your question a bit more. um So yes, we actually even have an example on that um for crypto, inventory management, and basically this this here, simulates uh dealing desk uh for selling cryptocurrencies this one, for example, on bitcoin, um but yes, demo can basically talk to any sort of other network that is out there and you can use data from demo in order to uh communicate to those and get kind of get data off of it.

B

You know pull data from from the blockchain to from that public blockchain to see uh what it is and then you know perform actions based on that as well. So, yes to answer your question very briefly: yes download it. Can you interoperate with any system out there excellent.

C

Thank you very much, and can we can we apply? um Also, like somebody raised a question on the pi right, pi data uh or uh even uh blocking uh the contract information beyond two parties?

C

uh Can we encrypt uh that data and put the encrypted contract into the uh into the into the ledger uh so that when only those two or maybe those three or maybe associated parties for that transaction uh can see it? Can we do that.

B

Yeah, you can obviously encrypt data before committing it to the chain and do it that way you could store hashes, which is another option for for that type of data privacy, um yeah there's there's several ways to basically protect data beyond just having permission sharing of it, and some of that I think we talked about in on the forum as well.

C

Thank you very much. That was a great question. Whoever raised that, you know, because the data is so public now yeah.

B

It is you're very welcome.

A

C

A

Other question mary rose.

C

Yeah, sorry, jim, yes and anthony thanks very much for the um presentation, I'm not a software developer or product owner, but I'm just doing a master's and high in blockchain at the moment in the aviation industry and I'm looking at hyperledger for a particular use case that I'm looking at. But um uh just on the the you know, hyperledger uses um private data collections as well to to safeguard some privacy between you know.

C

If there's information on the on a particular channel on a ledger, then you can use a private data collection between two of the nodes, then to share data is: does damon leverage that capability.

B

uh Demo, I don't believe leverages private data collections just yet, but I know we've been talking a bit about about those those functionalities.

A

And the other thing I would go back to what you said earlier anthony the point is there's multiple ways to in a sense ensure private data, so I don't have to um implement a private data collection, the implicit private data collections they have in fabric. There are other options for that for sure, yeah, absolutely they're, not fabric specific. Let's put that one.

C

Okay, okay, thank you and.

A

Back to the other point on tokens, um like fabric doesn't have a native token. There was a movement to try to create one um as far as crypto and all that the reality is um there's an application. We have that uh the team I work on wrote that actually uses uh the stellar network um and creates custom tokens out there. So some of these altcoin networks, like stellar's one there's a few others it actually let you in effect, say hey.

A

I wanna uh in a sense uh contract with you to create my own either crypto or my own token. You can do either one on these external networks and you know trade there, but those transactions can get captured in fabric as well. So so anyway, um anything else we've got to wrap up at one. But if there's one or more two questions I'd like to take them.

C

I've got a question if no one else has.

C

So in terms of of keeping uh data linked, but also private and and obscured, can you integrate zero knowledge proof data from other systems, either using canton or or otherwise? Or can you also use just hashed values of things that can be verified within demo for other chains.

B

On the zero knowledge proof side, I'm not 100 sure on that, so I wouldn't want to miss misrepresent. I know that there's been discussions on the canton side of various methods to make data private, but to answer the other part of your question. Yes, you can definitely use uh hash data in order to have some privacy that way as well great.

A

Yeah one other thing um so anthony I assume I will be able to get a pdf version of your slide deck uh yeah. I can definitely send that out all right, great and I'll. Take the record meeting recording here from zoom and the slide deck will post it up in the meetup and then the last thing I'll say is um you did point in fact, maybe you can show it on screen again. Is the url to ask questions in your community channel because there.

C

A

Questions people have wherever they.

B

Are yes, of course, so what you can do is uh the shortest link to type would be bit dot. Lee slash, try demo so I'll leave that up for a second just so everybody can see it and then the other just sort of screenshot noise. The other thing is uh to go directly. It's disgust.dalmal.com is our forum, where you can go ahead and ask questions the very active questions. Category.

A

So with that, um I want to thank you. This has been an awesome session. uh Certainly people were very interested in it and um it really does look like uh something that a fair amount of thought has gone into to try to simplify.

C

A

Contracts across multiple platforms, so it does look promising the fact that it's about an open source initiative is a big thing as well, so it looks very, very promising it's worth investigating. I think, and with that you know, um thank you very much and uh look forward to getting your slide deck and uh continuing to follow demo.

A

B

Absolutely thanks very much jim, uh that was a was a great little wrap up and yeah. Thank everybody for the questions you know sam may upon mary. You all ask great questions and if anybody has any others, uh like jim said, you can go to discuss.donald.com and yeah check it out. Thank you great thanks very much.

A

C

You thank you. Thank you. Thanks, sentry thanks.