near-lake-framework-rs

Available in programming languages: Rust | Javascript

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.

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Official NEAR Lake Framework High-level update announcement made on NEAR.org. This post announces the release of the beta version of the NEAR Lake Framework 0.8.0. The post also includes an overview of the new approach and features from the High-level update.

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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()
   );
}

For more information refer to the docs

Tutorials

• Video tutorial about near-examples/near-lake-accounts-watcher https://youtu.be/GsF7I93K-EQ
• Migrating to NEAR Lake Framework from NEAR Indexer Framework

More examples

We're keeping a set of examples in the examples folder. The examples there are always up-to-date with the latest version of the NEAR Lake Framework.

And here are some more examples. Despite the fact that they are not up-to-date with the latest version of the NEAR Lake Framework, they still can be used as a reference. Though, we try to keep them updated as well.

• near-examples/near-lake-raw-printer simple example of a data printer built on top of NEAR Lake Framework
• near-examples/near-lake-accounts-watcher another simple example of the indexer built on top of NEAR Lake Framework for a tutorial purpose
• near-examples/indexer-tx-watcher-example-lake an example of the indexer built on top of NEAR Lake Framework that watches for transactions related to specified account(s)
• octopus-network/octopus-near-indexer-s3 a community-made project that uses NEAR Lake Framework

How to use

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"

Cost estimates (Updated Mar 10, 2023 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.

84,400 blocks is approximate number of blocks per day (1 block per second * 60 seconds * 60 minutes * 24 hours)

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:

• MVP
• 0.8 High-level update
• 1.0