Herodotus Data Processor (HDP)

Warning: This codebase is experimental and not audited. Use at your own risk.

HDP enhances off-chain compute capabilities with zkVMs for verifiable on-chain data integration. For more, visit our documentation.

Introduction

The Data Processor CLI serves as an essential tool for developers working with Cairo programs and zkVM environments. Its primary function is to translate human-readable requests into a format compatible with Cairo programs, enabling commands to be executed over the Cairo VM and generating executable outputs. This transformation is a crucial preprocessing step that prepares data for off-chain computations in zkVM environments.

Features

• Development Tools: Encode and decode data lakes and computational tasks.
• Core Processing: Compile data from various sources and compute aggregate functions.
• Extensibility: Support for multiple blockchain integrations and various ZKVM backends is planned.
• Ease of Use: Provides a CLI for easy interaction with the system.

Install HDP

Install with cargo

# Install with cargo
❯ cargo install --git https://github.com/HerodotusDev/hdp --locked --force

Build from source

# clone repo
❯ git clone https://github.com/HerodotusDev/hdp.git

# install hdp
❯ cargo install --path cli -f

Getting Started

To launch the interactive CLI:

# Start the HDP
❯ hdp start
Welcome to Herodotus Data Processor interactive CLI! 🛰️

                _   _   ____    ____
                | | | | |  _ \  |  _ \
                | |_| | | | | | | |_) |
                |  _  | | |_| | |  __/
                |_| |_| |____/  |_|

? Step 1. What's your datalake type?

Usage Examples

The following examples demonstrate how to use the HDP CLI to encode various blockchain data elements into a format suitable for processing. Each command highlights a different function of the HDP system, from averaging values to counting values based on specific criteria.

Header value with AVG:

hdp encode "avg" -b 4952100 4952110 "header.base_fee_per_gas" 1

Account value with SUM:

hdp encode "sum" -b 4952100 4952110 "account.0x7f2c6f930306d3aa736b3a6c6a98f512f74036d4.nonce" 2

Storage value with AVG:

hdp encode "avg" -b 5382810 5382820 "storage.0x75CeC1db9dCeb703200EAa6595f66885C962B920.0x0000000000000000000000000000000000000000000000000000000000000002" 1

Account value with COUNT:

hdp encode "count" "gt.1000" -b 4952100 4952110 "account.0x7f2c6f930306d3aa736b3a6c6a98f512f74036d4.nonce" 2

After encoding, you can directly run processing tasks using environmental configurations for RPC and Chain ID, as shown below:

# pro tip: run herodotus data processing with `.env`
hdp run

# run herodotus data processing
hdp run ${Encoded Task} ${Encoded Datalake} ${Input your RPC Provider -- this example is Etherum Sepolia} ${Input Chain ID that you are target on}

For a more comprehensive guide on commands available within HDP CLI:

❯ hdp --help
Interact Herodotus Data Processor via CLI

Usage: hdp <COMMAND>

Commands:
  start       New to the HDP CLI? Start here!
  encode      Encode the task and datalake in batched format test purposes
  decode      Decode batch tasks and datalakes
  decode-one  Decode one task and one datalake (not batched format)
  run         Run the evaluator
  help        Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version

Integration Testing

Integration testing in HDP ensures that the functionality of aggregate functions such as SUM, AVG, MIN, MAX, and COUNT operates correctly across various numeric fields within the blockchain data structure. These functions are designed specifically for numeric data types, ensuring accurate and reliable computations.

Integration Test

The core soundness of HDP relies on generating the correct input file and running the Cairo program. To ensure this, a full integration test flow is necessary to link the pre-processor and processor versions. For continuous integration tests, please refer to the hdp-test repository as it contains all the cases of supported features in table below.

Supported Aggregate Functions

• SUM, AVG, MIN, MAX, COUNT: These functions are supported only for fields with numeric values.
• SLR: Simple linear regression written in Cairo 1. The input array should contain more than 2 elements.

Function Support Matrix

Here is the support matrix indicating which blockchain elements are tested for each aggregate function. The matrix highlights fields where these functions are applicable.

Field Description	SUM	AVG	MIN	MAX	COUNT	SLR
account.nonce	✅	✅	✅	✅	✅	✅
account.balance	✅	✅	✅	✅	✅	✅
account.storage_root	-	-	-	-	-	-
account.code_hash	-	-	-	-	-	-
storage.key (numeric value)	✅	✅	✅	✅	✅	✅
storage.key (hash value)	-	-	-	-	-	-
header.difficulty	✅	✅	✅	✅	✅	✅
header.gas_limit	✅	✅	✅	✅	✅	✅
header.gas_used	✅	✅	✅	✅	✅	✅
header.timestamp	✅	✅	✅	✅	✅	✅
header.base_fee_per_gas	✅	✅	✅	✅	✅	✅
header.blob_gas_used	✅	✅	✅	✅	✅	✅
header.excess_blob_gas	✅	✅	✅	✅	✅	✅
header.nonce	✅	✅	✅	✅	✅	✅
Other header elements	-	-	-	-	-	-
tx.nonce	✅	✅	✅	✅	✅	✅
tx.gas_price	✅	✅	✅	✅	✅	✅
tx.gas_limit	✅	✅	✅	✅	✅	✅
tx.value	✅	✅	✅	✅	✅	✅
tx.v	✅	✅	✅	✅	✅	✅
tx.r	✅	✅	✅	✅	✅	✅
tx.s	✅	✅	✅	✅	✅	✅
tx.chain_id	✅	✅	✅	✅	✅	✅
tx.max_fee_per_gas	✅	✅	✅	✅	✅	✅
tx.max_priority_fee_per_gas	✅	✅	✅	✅	✅	✅
tx.max_fee_per_blob_gas	✅	✅	✅	✅	✅	✅
Other tx elements	-	-	-	-	-	-

Note: Fields marked with "-" are not applicable for the specified aggregate functions because they do not contain numeric data or the data type is not suitable for these calculations.

Additional Notes

• Please ensure that the data fields you are applying these functions contain numeric values to avoid computational errors.
• For details on how these tests are performed or to contribute to the further development of tests, please refer to the Integration Test Guide.

Development

# CI check
cargo make run-ci-flow

Defining Your Own Module

For developers interested in extending the functionality of HDP by adding new modules, follow the steps outlined below. This guide assumes a basic understanding of Rust and its module system.

Getting Started

1. Module Location: Start by creating a new module within the aggregate_fn directory. You can find this at aggregation_fn/mod.rs.

2. Define Enum: Define your new function as an enum in the file. Make sure to add match arms for the new enum variants in the implementation.

3. Handle Data Types: Depending on the expected input type for your function:

   • Integer Inputs: Use U256 for handling large integers compatible with Ethereum's numeric constraints.
   • String Inputs: Use Rust's standard String type for text data.

Context Required Operation

For a practical example of how to implement context-sensitive operations, refer to the implementation of the COUNT function. This example shows how to pass and utilize additional context for operations, which can be particularly useful for conditional processing or complex calculations.

During SLR computation, we also need a context to use as the target index for computation. Since SLR is not supported during the preprocessing step, we simply pass the encoded task that contains the function context, and the Cairo program will handle this computation based on the provided index.

Testing Your Module

After implementing your new function, it's crucial to verify its functionality:

• Create Unit Tests: Add tests in the corresponding test file in the tests directory. Ensure your tests cover all new logic to maintain stability and reliability.
• Test for Integer Types: Pay special attention to functions that handle integer types, ensuring they correctly process and output values fitting within a bytes32 length, reflecting Ethereum's data type constraints.

License

hdp is licensed under the GNU General Public License v3.0.

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Herodotus Dev Ltd - 2024