Ethereum caching proxy

Topics

• Overview
• Settings
• Usage
  • Build
  • Tests
  • Linter
  • Build Docker image
  • Run in Docker
• Endpoints
  • Block
• Returned errors

Overview

Ethproxy is a service providing LRU cache for API method eth_getBlockByNumber backed by Cloudflare gateway.

• It uses CCache as its cache engine.
• Singleflight to prevent simultaneous requests to a single block
• Configuration using envconfig
• Latest 20 blocks have a default TTL of 5 seconds. Blocks from 20 to 1000 have TTL="distance from latest" * 5s
• All blocks further than 1000 from the latest are considered immutable
• Requesting an expired cache item does not block the service. It refreshes the requested block in background
• Implements graceful shutdown
• Linter support
• Docker image building. Due to the multi-stage static build, the resulting image size is less than 6 mb

Settings

env	Default value
ETHPROXY_LOG_LEVEL	info
ETHPROXY_LISTEN_ADDRESS	:8080
ETHPROXY_CLIENT_TIMEOUT	5s
ETHPROXY_READ_TIMEOUT	5s
ETHPROXY_WRITE_TIMEOUT	5s
ETHPROXY_CACHE_SIZE	5000

Usage

Build

make build

Tests

make tests

Linter

make lint

Build docker image

make dockerise

Run in Docker

make docker_run

Endpoints

Block

• GET /block/<block number>/txs/<tx>

block number is either "latest", or a decimal block number.

tx is either decimal transaction index or tx hash.

Response:

HTTP 200 OK

{
    "blockHash":"0x1d59ff54b1eb26b013ce3cb5fc9dab3705b415a67127a003c3e61eb445bb8df2",
    "blockNumber":"0x5daf3b", // 6139707
    "from":"0xa7d9ddbe1f17865597fbd27ec712455208b6b76d",
    "gas":"0xc350", // 50000
    "gasPrice":"0x4a817c800", // 20000000000
    "hash":"0x88df016429689c079f3b2f6ad39fa052532c56795b733da78a91ebe6a713944b",
    "input":"0x68656c6c6f21",
    "nonce":"0x15", // 21
    "to":"0xf02c1c8e6114b1dbe8937a39260b5b0a374432bb",
    "transactionIndex":"0x41", // 65
    "value":"0xf3dbb76162000", // 4290000000000000
    "v":"0x25", // 37
    "r":"0x1b5e176d927f8e9ab405058b2d2457392da3e20f328b16ddabcebc33eaac5fea",
    "s":"0x4ba69724e8f69de52f0125ad8b3c5c2cef33019bac3249e2c0a2192766d1721c"
}

Returned errors

HTTP code	description
404	block not found
404	transaction not found
400	block number too high
502	Bad gateway (Cloudflare returned an error)
500	Internal server error