Crate near_lake_framework

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§NEAR Lake Framework

NEAR Lake Framework is a small library companion to NEAR Lake. It allows you to build your own indexer that subscribes to the stream of blocks from the NEAR Lake data source and create your own logic to process the NEAR Protocol data.

§Example

use futures::StreamExt;
use near_lake_framework::LakeConfigBuilder;

#[tokio::main]
async fn main() -> Result<(), tokio::io::Error> {
   // create a NEAR Lake Framework config
   let config = LakeConfigBuilder::default()
       .testnet()
       .start_block_height(82422587)
       .build()
       .expect("Failed to build LakeConfig");

   // instantiate the NEAR Lake Framework Stream
   let (sender, stream) = near_lake_framework::streamer(config);

   // read the stream events and pass them to a handler function with
   // concurrency 1
   let mut handlers = tokio_stream::wrappers::ReceiverStream::new(stream)
       .map(|streamer_message| handle_streamer_message(streamer_message))
       .buffer_unordered(1usize);

   while let Some(_handle_message) = handlers.next().await {}
   drop(handlers); // close the channel so the sender will stop

   // propagate errors from the sender
   match sender.await {
       Ok(Ok(())) => Ok(()),
       Ok(Err(e)) => Err(e),
       Err(e) => Err(anyhow::Error::from(e)), // JoinError
   }
}

// The handler function to take the entire `StreamerMessage`
// and print the block height and number of shards
async fn handle_streamer_message(
   streamer_message: near_lake_framework::near_indexer_primitives::StreamerMessage,
) {
   eprintln!(
       "{} / shards {}",
       streamer_message.block.header.height,
       streamer_message.shards.len()
   );
}

§Tutorials:

§More examples

§How to use

§AWS S3 Credentials

In order to be able to get objects from the AWS S3 bucket you need to provide the AWS credentials.

§Passing credentials to the config builder
use near_lake_framework::LakeConfigBuilder;

let credentials = aws_credential_types::Credentials::new(
    "AKIAIOSFODNN7EXAMPLE",
    "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY",
    None,
    None,
    "custom_credentials",
);
let s3_config = aws_sdk_s3::Config::builder()
    .credentials_provider(credentials)
    .build();

let config = LakeConfigBuilder::default()
     .s3_config(s3_config)
     .s3_bucket_name("near-lake-data-custom")
     .start_block_height(1)
     .build()
     .expect("Failed to build LakeConfig");

You should never hardcode your credentials, it is insecure. Use the described method to pass the credentials you read from CLI arguments

§File-based AWS credentials

AWS default profile configuration with aws configure looks similar to the following:

~/.aws/credentials

[default]
aws_access_key_id=AKIAIOSFODNN7EXAMPLE
aws_secret_access_key=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY

AWS docs: Configuration and credential file settings

§Environmental variables

Alternatively, you can provide your AWS credentials via environment variables with constant names:

$ export AWS_ACCESS_KEY_ID=AKIAIOSFODNN7EXAMPLE
$ AWS_SECRET_ACCESS_KEY=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
$ AWS_DEFAULT_REGION=eu-central-1

§Dependencies

Add the following dependencies to your Cargo.toml

...
[dependencies]
futures = "0.3.5"
itertools = "0.10.3"
tokio = { version = "1.1", features = ["sync", "time", "macros", "rt-multi-thread"] }
tokio-stream = { version = "0.1" }

# NEAR Lake Framework
near-lake-framework = "0.6.1"

§Custom S3 storage

In case you want to run your own near-lake instance and store data in some S3 compatible storage (Minio or Localstack as example) You can owerride default S3 API endpoint by using s3_endpoint option

  • run minio
$ mkdir -p /data/near-lake-custom && minio server /data

use aws_sdk_s3::Endpoint;
use http::Uri;
use near_lake_framework::LakeConfigBuilder;

let aws_config = aws_config::from_env().load().await;
let mut s3_conf = aws_sdk_s3::config::Builder::from(&aws_config);
s3_conf = s3_conf
    .endpoint_resolver(
            Endpoint::immutable("http://0.0.0.0:9000".parse::<Uri>().unwrap()))
    .build();

let config = LakeConfigBuilder::default()
    .s3_config(s3_conf)
    .s3_bucket_name("near-lake-data-custom")
    .start_block_height(1)
    .build()
    .expect("Failed to build LakeConfig");

§Configuration

Everything should be configured before the start of your indexer application via LakeConfigBuilder struct.

Available parameters:

§Cost estimates (Updated Mar 10, 2022 with more precise calculations)

TL;DR approximately $20 per month (for AWS S3 access, paid directly to AWS) for the reading of fresh blocks

§Historical indexing

| Blocks | GET | LIST | Subtotal GET | Subtotal LIST | Total $ | |—|—|—|—|—|—| | 1000 | 5000 | 4 | 0.00215 | 0.0000216 | $0.00 | | 86,400 | 432000 | 345.6 | 0.18576 | 0.00186624 | $0.19 | | 2,592,000 | 12960000 | 10368 | 5.5728 | 0.0559872 | $5.63 | | 77,021,059 | 385105295 | 308084.236 | 165.5952769 | 1.663654874 | $167.26 |

Note: ~77m of blocks is the number of blocks on the moment I was calculating.

2,592,000 blocks is approximate number of blocks per months (86,400 blocks per day * 30 days)

§Tip of the network indexing

| Blocks | GET | LIST | Subtotal GET | Subtotal LIST | Total $ | |—|—|—|—|—|—| | 1000 | 5000 | 1000 | 0.00215 | 0.0054 | $0.01 | | 86,400 | 432000 | 86,400 | 0.18576 | 0.46656 | $0.65 | | 2,592,000 | 12960000 | 2,592,000 | 5.5728 | 13.9968 | $19.57 | | 77,021,059 | 385105295 | 77,021,059 | 165.5952769 | 415.9137186 | $581.51 |

Explanation:

Assuming NEAR Protocol produces accurately 1 block per second (which is really not, the average block production time is 1.3s). A full day consists of 86400 seconds, that’s the max number of blocks that can be produced.

According the Amazon S3 prices list requests are charged for $0.0054 per 1000 requests and get is charged for $0.00043 per 1000 requests.

Calculations (assuming we are following the tip of the network all the time):

86400 blocks per day * 5 requests for each block / 1000 requests * $0.0004 per 1k requests = $0.19 * 30 days = $5.7

Note: 5 requests for each block means we have 4 shards (1 file for common block data and 4 separate files for each shard)

And a number of list requests we need to perform for 30 days:

86400 blocks per day / 1000 requests * $0.005 per 1k list requests = $0.47 * 30 days = $14.1

$5.7 + $14.1 = $19.8

The price depends on the number of shards

§Future plans

We use Milestones with clearly defined acceptance criteria:

Re-exports§

Modules§

Structs§

Functions§

  • streamer
    Creates mpsc::channel and returns the receiver to read the stream of StreamerMessage