Price Prover CLI

UserStory

User Alice, want to exchange aUSD with aIBM. She need to submit a transaction to our exchange contract, with this info: (aUSD->aIBM, amount, price of aIBM, proof of price of aIBM, timestamp). And exchange contract determines the validity of the info and execute the exchange on valid.

In the first version, the process to fetch this info is wrapped in a CLI, we call it “Price Prover CLI”. Alice provides “aUSD->aIBM” as parameter to the CLI. The CLI does the following:

trigger tls-notary client pagesigner-cli, to obtain the HTTPS response of the price data JSON and a notary file.

preprocess the price data JSON and notary file to circuit input.

feed the input to circuit and generate a proof file.

create a transaction payload: call price contract’s submit_price method, with argument: (aIBM, price of aIBM, proof, content, timestamp)

Usage

This CLI is built on picocli.

(Optional) define an alias:

alias priceprover='java -cp priceprover-0.0.2.jar com.abstrlabs.priceprover.PriceProver

Usage: priceprover [-hVv] [-fi] [-as=<asset>] [-op=<outputPath>] [COMMAND]

given the stock symbol, notarize the price and generate the proof

-as, --asset           the asset name used to obtain the price data.

-fi, --firstTime       if it is first time run

-h, --help             show help message and exit.

-op, --outputPath      output path for generated files

-v, --verbose          specify multiple -v options to increase verbosity.
                       for example, `-v` - info, '-vv' - debug,'-vvv' -trace
                       
-V, --version          print version information and exit.

SubCommands:
notarize  Call pagesigner-cli and notarize the stock price
build     Parse the notary json from pagesinger, and build the circuit/input
by xjsnark
prove     Trigger libsnark and generate the proof

For User

Run Executable priceprover Across OS

1. Download executable from drive links:
   1. Mac: link
   2. Linux: link
2. Run below command to show help message

./priceprover -h

Note: Image 'priceprover' is a fallback image that requires a JDK for execution.

For Developer

Build

(Please install maven if you haven't).

Before first build, add xjsnark-1.0.jar to local maven repository:

mvn install:install-file -Dfile=depends/akosba/xjsnark/1.0/xjsnark-1.0.jar -DgroupId=akosba -DartifactId=xjsnark -Dversion=1.0 -Dpackaging=jar

To build an executable jar:

mvn clean compile assembly:single

Create Executable via GraalVM Native Image

Prerequisites

• macOS:

1. install GraalVM

brew install --cask graalvm/tap/graalvm-ce-java8

2. install Compiler Toochain

mac: xcode-select --install

3. install native-image

gu install native-image

4. set JAVA_HOME variable to the GraalVM installation directory

export JAVA_HOME=/Library/Java/JavaVirtualMachines/graalvm-ce-java8-21.0.0.2/Contents/Home

5. Point the PATH environment variable to the GraalVM bin directory:

export PATH=$PATH:$JAVA_HOME/bin

• Linux:

1. install GraalVM

wget https://github.com/graalvm/graalvm-ce-builds/releases/download/vm-19.3.6/graalvm-ce-java8-linux-amd64-19.3.6.tar.gz
tar -xzf graalvm-ce-java8-linux-amd64-19.3.6.tar.gz

2. install Compiler Toochain see https://www.graalvm.org/22.1/reference-manual/native-image/#prerequisites

3. install native-image

gu install native-image

4. set JAVA_HOME variable to the GraalVM installation directory

export JAVA_HOME=/path/to/GraalVM/graalvm-ce-java8-19.3.6

5. Point the PATH environment variable to the GraalVM bin directory:

export PATH=$PATH:$JAVA_HOME/bin

• Windows: - TBD

Create a Native Image with picocli

After succeed build via maven, an executable jar will be generated under target/ folder.

Run below command to create a native image [priceprover].

native-image -cp picocli-4.6.3.jar --static -jar target/priceprover-0.0.3-jar-with-dependencies.jar priceprover

Q&A

Cannot run program "./depends/libsnark/run_ppzksnark": error=13, Permission denied

Try chmod u+x ./depends/libsnark/run_ppzksnark

References