Warning I've stopped maintaining ette.

ette

EVM-based Blockchain Indexer, with historical data query & real-time notification support 😎

Deploy your ette instance today

Table of Contents

• Why did you build ette ?
• What do I need to have to use it ?
• How to install it ?
• What are possible use cases of ette ?
• How do I generate APIKey(s) ?
• How to use it ?
  • Historical Data
    • Custom REST
      • Query historical block data
      • Query historical transaction data
      • Query historical event data
    • GraphQL ( Recommended )
      • Query historical block data
      • Query historical transaction data
      • Query historical event data
  • Real-time Data
    • Real-time block mining notification
    • Real-time transaction notification ( 🤩 Filters Added )
    • Real-time log event notification ( 🤩 Filters Added )
  • Snapshotting
    • Take snapshot
    • Restore from snapshot

Inspiration 🤔

I was looking for one tool which will be able to keep itself in sync with latest happenings on EVM based blockchain i.e. index blockchain data, while exposing REST & GraphQL API for querying blockchain data with various filters. That tool will also expose real time notification functionalities over websocket, when subscribed to topics.

It's not that I was unable find any solution, but wasn't fully satisfied with those, so I decided to write ette, which will do following

• Sync upto latest state of blockchain

• Listen for all happenings on EVM based blockchain

• Persist all happenings in local database

• Expose REST & GraphQL API for querying 👇, while also setting block range/ time range for filtering results. Allow querying latest X entries for events emitted by contracts.

  • Block data
  • Transaction data
  • Event data

• Expose websocket based real time notification mechanism for

  • Blocks being mined
  • Transactions being sent from address and/ or transactions being received at address
  • Events being emitted by contract, with indexed fields i.e. topics

• All historical data query requests must carry authentication header as APIKey, which can be generated by users, using webUI, packed with ette.

• All real-time event subscription & unsubscription requests must carry apiKey in their payload.

• It has very minimalistic webUI for creating & managing APIKey(s).

• It has capability to process blocks in delayed fashion, if asked to do so. To address chain reorganization issue, this is very effective. All you need to do, specify how many block confirmations you require before considering that block to be finalized in .env file. Now ette will do everything with block ( if real-time subscription mode is enabled, it'll publish data to clients who're interested i.e. subscribed ) expect putting it in persistent data store. Rather block identifier to be put in waiting queue, from where it'll be eventually picked up by workers to finally persist it in DB. Only downside of using this feature is you might not get data back in response of query for certain block number, which just got mined but not finalized as per your set up i.e. BlockConfirmations environment variable's value. You can always skip it, default value will be 0.

• ette can help you in taking snapshot of whole database, it's relying on, into a single binary file, where block data is serialized into Protocol Buffer format, efficient for deserialization also i.e. while restoring back from snapshot.

  • EtteMode = 4, attempts to take a snapshot of whole database.

• Restoring from snapshoted data file, can be attempted by ette when EtteMode = 5. Make sure you've cleaned backing data store before so & recreated database. [ Table migration to be automatically taken care of ]

• For snapshotting purposes, you can always set sink/ source data file in SnapshotFile in .env.

• 👆 snapshotting feature is helpful, if you're willing migrate ette to different machine or setting up new instance of ette. If you want to avoid a lengthy whole chain data syncing, you must take snapshot from existing instance of ette & attempt to restore from binary snapshot file in new ette instance.

And that's ette

Prerequisite 👍

• Make sure you've Go ( >= 1.15 ) installed
• You need to also install & set up PostgreSQL. I found this guide helpful.

Make sure you've pgcrypto extension enabled on PostgreSQL Database.

Check existing extensions using : \dx

Create extension using : create extension pgcrypto;

• Redis needs to be installed too. Consider following this guide.

Note : Redis v6.0.6 is required

Note : Setting password in Redis instance has been made optional from now on, though it's recommended.

• Blockchain Node's both HTTP & Websocket connection URL required, because we'll be querying block, transaction, event log related data using HTTP interface & listening for block mining events in real time over Websocket.

Installation 🛠

• First fork this repository & clone it, some where out side of GOPATH.

git clone git@github.com:username/ette.git

• Now get inside ette

cd ette

• Create a .env file in this directory.

  • Make sure PostgreSQL has md5 authentication mechanism enabled.
  • Please enable password based authentication in Redis Server
  • Skipping RedisPassword is absolutely fine, if you don't want to use any password in Redis instance. [ Not recommended ]
  • Replace Domain with your domain name i.e. ette.company.com
  • Set Production to yes before running it in production; otherwise you can simply skip it
  • ette can be run in any of 👇 5 possible modes, which can be set by EtteMode

  ---

  EtteMode	Interpretation
  1	Only Historical Data Query Allowed
  2	Only Real-time Subscription Allowed
  3	Both Historical Data Query & Real-time Subscription Allowed
  4	Attempt to take snapshot from data in backing DB
  5	Attempt to restore data from snapshot file

  ---

  • For testing historical data query using browser based GraphQL Playground in ette, you can set EtteGraphQLPlayGround to yes in config file
  • For processing block(s)/ tx(s) concurrently, it'll create ConcurrencyFactor * #-of CPUs on machine workers, who will pick up jobs submitted to them.
  • If nothing is specified, it defaults to 1 & assuming you're running ette on machine with 4 CPUs, it'll spawn worker pool of size 4. But more number of jobs can be submitted, only 4 can be running at max.
  • 👆 being done for controlling concurrency level, by putting more control on user's hand.
  • If you want to persist blocks in delayed fashion, you might consider setting BlockConfirmations to some number > 0.
  • That will make ette think you're asking it 80 is latest block, which can be persisted in final data store, when latest mined block number is 100 & BlockConfirmations is set to 20.
  • This option is recommended to be used, at least in production, to address chain reorganization issue.
  • For range based queries BlockRange can be set to limit how many blocks can be queried by client in a single go. Default value 100.
  • For time span based queries TimeRange can be set to put limit on max time span ( in terms of second ), can be used by clients. Default value 3600 i.e. 1 hour.
  • If you're attempting to take snapshot/ restore from binary snapshot file, you can set SnapshotFile in .env file, to set sink/ source file name, respectively. Default file name echo $(echo $(pwd)/snapshot.bin) in i.e. from where ette gets invoked. Consider setting EtteMode correctly, depending upon what you want to attain.

RPCUrl=https://<domain-name>
WebsocketUrl=wss://<domain-name>
PORT=7000
DB_USER=user
DB_PASSWORD=password
DB_HOST=x.x.x.x
DB_PORT=5432
DB_NAME=ette
RedisConnection=tcp
RedisAddress=x.x.x.x:6379
RedisPassword=password
Domain=localhost
Production=yes
EtteMode=3
EtteGraphQLPlayGround=yes
ConcurrencyFactor=5
BlockConfirmations=200
BlockRange=1000
TimeRange=21600
SnapshotFile=snapshot.bin

• Create another file in same directory, named .plans.json, whose content will look like 👇.

  • This file holds subscription plans for clients, allowed by this ette instance.
  • Each plan is denoted by one unique name & deliveryCount, where deliveryCount denotes number of times data to be delivered to client application in 24 hours of time span.
  • Because each request must be accompanied with APIKey, ette knows which user is requesting for resources & how many were delivered successfully in last 24 hours of time span.
  • If one user crosses allowed request limit in 24 hours, no new request will be taken under consideration & any existing connection will stop delivering data to client.

Quick Tip : Setting deliveryCount is fully upto you. Please consider VM specifications before doing so.

{
    "plans": [
        {
            "name": "TIER 1",
            "deliveryCount": 50000
        },
        {
            "name": "TIER 2",
            "deliveryCount": 100000
        },
        {
            "name": "TIER 3",
            "deliveryCount": 500000
        },
        {
            "name": "TIER 4",
            "deliveryCount": 750000
        },
        {
            "name": "TIER 5",
            "deliveryCount": 1000000
        }
    ]
}

• Now build ette

make build

• If everything goes as expected, you'll find one binary named, ette in this directory. Run it.

./ette

# or directly run `ette` using 👇, which will first build, then run
make run

• Database migration to be taken care of during application start up.
• Syncing ette with latest state of blockchain takes time. Current sync state can be queried

curl -s localhost:7000/v1/synced | jq

• You'll receive response of form 👇

{
  "elapsed": "3m2.487237s",
  "eta": "87h51m38s",
  "processed": 4242,
  "synced": "0.35 %"
}

• You can check how many active websocket sessions being managed by your ette deployment by

curl -s localhost:7000/v1/stat | jq

---

Production deployment of ette using systemd

Here's a systemd unit file which you can create in /etc/systemd/system.

sudo touch /etc/systemd/system/ette.service # first do it

Now you can paste 👇 content in unit file, given that you've cloned ette in $HOME.

[Unit]
Description=ette - EVM Blockchain Indexer

[Service]
User=ubuntu
WorkingDirectory=/home/ubuntu/ette
ExecStart=/home/ubuntu/ette/ette
Restart=on-failure
RestartSec=10s

[Install]
WantedBy=multi-user.target

Time to load systemd.

sudo systemctl daemon-reload

Now you can enable ette, so that it can be automatically started after system boot up.

sudo systemctl enable ette.service

Finally you can start ette.

sudo systemctl start ette.service

You can also stop, running ette instance.

sudo systemctl stop ette.service

Restart an instance.

sudo systemctl restart ette.service

All logs ette produces can be inspected using 👇

sudo journalctl -u ette.service # oldest to newest
sudo journalctl -u ette.service --reverse # opposite of 👆

Latest log can be followed

sudo journalctl -u ette.service -f

---

Use Cases 🤯

ette is supposed to be deployed by anyone, interested in running a historical data query & real-time notification service for EVM-based blockchain(s).

All client requests are by default rate limited ( 50k requests/ day ). This rate limit is enforced on all APIKey(s) created by any single Ethereum Address. You can create multiple APIKey(s) from your account & accumulated requests made from those keys to be considered before dropping your requests.

If you need more requests per day, you can always asked your ette administrator to manually increase that from database table. [ Risky operation, needs to be done carefully. This is not recommended. ]

More features coming here, soon

Management using webUI 🖥

ette has one minimalistic webUI for generating & managing APIKey(s). It doesn't have any password based login mechanism. You need to have Metamask browser plugin installed for logging into ette management webUI.

Once you've started ette on your machine, open browser & head to http://localhost:7000/v1/login.

You'll be greeted with 👇

Assuming you've Metamask browser plugin installed, you can click Login & you'll be asked to sign a message of specific format, which will be validated by ette.

Once logged in, you can find out all APIKey(s) created by you.

If you've not any APIKey(s) created yet, go ahead & click Create new app. Again you'll be asked to sign a message of specific format.

And you'll see new APIKey on your screen.

You can create any number of APIKey(s), but rate limiting to be applied on aggregated requests from all those APIKey(s).

Now go ahead & use APIKey in header of historical data query requests/ payload of real-time notification subscription/ unsubscription request.

Double clicking on created APIKey toggles its enabled state, which is represented visually. 👇

Enabled	Text Color
Yes	Green
No	Red

Quick Tip: As you can create any number of APIKey(s) from one Ethereum address, if you feel any of those has been exposed, disabling those ensures all requests accompanied with those APIKey(s) to be dropped, by ette

Read further for usage examples.

Usage 🦾

ette exposes REST & GraphQL API for querying historical block, transaction & event related data. It can also play role of real time notification engine, when subscribed to supported topics.

All historical data query requests need to be strictly accompanied with valid APIKey as request header param 🤖

Historical Block Data ( REST API ) 🤩

You can query historical block data with various combination of query string params. 👇 is a comprehensive guide for consuming block data.

Path : /v1/block

Example code snippet can be found here

Query Params	Method	Description
hash=0x...&tx=yes	GET	Fetch all transactions present in a block, when block hash is known
number=1&tx=yes	GET	Fetch all transactions present in a block, when block number is known
hash=0x...	GET	Fetch block by hash
number=1	GET	Fetch block by number
fromBlock=1&toBlock=10	GET	Fetch blocks by block number range ( max 10 at a time )
fromTime=1604975929&toTime=1604975988	GET	Fetch blocks by unix timestamp range ( max 60 seconds timespan )

Historical Transaction Data ( REST API ) 😎

It's possible to query historical transactions data with various combination of query string params, where URL path is 👇

Path : /v1/transaction

Example code snippet can be found here

Query Params	Method	Description
hash=0x...	GET	Fetch transaction by txHash
nonce=1&fromAccount=0x...	GET	Fetch transaction, when tx sender's address & account nonce are known
fromBlock=1&toBlock=10&deployer=0x...	GET	Find out what contracts are created by certain account within given block number range ( max 100 blocks )
fromTime=1604975929&toTime=1604975988&deployer=0x...	GET	Find out what contracts are created by certain account within given timestamp range ( max 600 seconds of timespan )
fromBlock=1&toBlock=100&fromAccount=0x...&toAccount=0x...	GET	Given block number range ( max 100 at a time ) & a pair of accounts, can find out all tx performed between that pair, where from & to fields are fixed
fromTime=1604975929&toTime=1604975988&fromAccount=0x...&toAccount=0x...	GET	Given time stamp range ( max 600 seconds of timespan ) & a pair of accounts, can find out all tx performed between that pair, where from & to fields are fixed
fromBlock=1&toBlock=100&fromAccount=0x...	GET	Given block number range ( max 100 at a time ) & an account, can find out all tx performed from that account
fromTime=1604975929&toTime=1604975988&fromAccount=0x...	GET	Given time stamp range ( max 600 seconds of span ) & an account, can find out all tx performed from that account
fromBlock=1&toBlock=100&toAccount=0x...	GET	Given block number range ( max 100 at a time ) & an account, can find out all tx where target was this address
fromTime=1604975929&toTime=1604975988&toAccount=0x...	GET	Given time stamp range ( max 600 seconds of span ) & an account, can find out all tx where target was this address

Historical Event Data ( REST API ) 🧐

ette lets you query historical event data, emitted by smart contracts, by combination of query string params.

Path : /v1/event

Query Params	Method	Description
blockHash=0x...	GET	Given blockhash, retrieves all events emitted by tx(s) present in block
blockHash=0x...&logIndex=1	GET	Given blockhash and log index in block, attempts to retrieve associated event
blockNumber=123456&logIndex=2	GET	Given block number and log index in block, attempts to retrieve associated event
txHash=0x...	GET	Given txhash, retrieves all events emitted during execution of this transaction
count=50&contract=0x...	GET	Returns last x ( <=50 ) events emitted by this contract
fromBlock=1&toBlock=10&contract=0x...&topic0=0x...&topic1=0x...&topic2=0x...&topic3=0x...	GET	Finding event(s) emitted from contract within given block range & also matching topic signatures {0, 1, 2, 3}
fromBlock=1&toBlock=10&contract=0x...&topic0=0x...&topic1=0x...&topic2=0x...	GET	Finding event(s) emitted from contract within given block range & also matching topic signatures {0, 1, 2}
fromBlock=1&toBlock=10&contract=0x...&topic0=0x...&topic1=0x...	GET	Finding event(s) emitted from contract within given block range & also matching topic signatures {0, 1}
fromBlock=1&toBlock=10&contract=0x...&topic0=0x...	GET	Finding event(s) emitted from contract within given block range & also matching topic signatures {0}
fromBlock=1&toBlock=10&contract=0x...	GET	Finding event(s) emitted from contract within given block range
fromTime=1604975929&toTime=1604975988&contract=0x...&topic0=0x...&topic1=0x...&topic2=0x...&topic3=0x...	GET	Finding event(s) emitted from contract within given time stamp range & also matching topic signatures {0, 1, 2, 3}
fromTime=1604975929&toTime=1604975988&contract=0x...&topic0=0x...&topic1=0x...&topic2=0x...	GET	Finding event(s) emitted from contract within given time stamp range & also matching topic signatures {0, 1, 2}
fromTime=1604975929&toTime=1604975988&contract=0x...&topic0=0x...&topic1=0x...	GET	Finding event(s) emitted from contract within given time stamp range & also matching topic signatures {0, 1}
fromTime=1604975929&toTime=1604975988&contract=0x...&topic0=0x...	GET	Finding event(s) emitted from contract within given time stamp range & also matching topic signatures {0}
fromTime=1604975929&toTime=1604975988&contract=0x...	GET	Finding event(s) emitted from contract within given time stamp range

Historical Block Data ( GraphQL API ) 🤩

You can query block data using GraphQL API.

Path: /v1/graphql

Method: POST

type Query {
    blockByHash(hash: String!): Block!
    blockByNumber(number: String!): Block!
    blocksByNumberRange(from: String!, to: String!): [Block!]!
    blocksByTimeRange(from: String!, to: String!): [Block!]!
}

Response will be of type 👇

type Block {
  hash: String!
  number: String!
  time: String!
  parentHash: String!
  difficulty: String!
  gasUsed: String!
  gasLimit: String!
  nonce: String!
  miner: String!
  size: Float!
  txRootHash: String!
  receiptRootHash: String!
}

Method	Parameters	Possible use case
blockByHash	hash: String!	When you know block hash & want to get whole block data back
blockByNumber	number: String!	When you know block number & want to get whole block data back
blocksByNumberRange	from: String!, to: String!	When you've a block number range & want to get all blocks in that range, in a single call
blocksByTimeRange	from: String!, to: String!	When you've unix timestamp range & want to get all blocks in that range, in a single call

---

Historical Transaction Data ( GraphQL API ) 🤩

You can query transaction data from ette, using following GraphQL methods.

Path: /v1/graphql

Method: POST

type Query {
    transaction(hash: String!): Transaction!
  
    transactionCountByBlockHash(hash: String!): Int!
    transactionsByBlockHash(hash: String!): [Transaction!]!
  
    transactionCountByBlockNumber(number: String!): Int!
    transactionsByBlockNumber(number: String!): [Transaction!]!
  
    transactionCountFromAccountByNumberRange(account: String!, from: String!, to: String!): Int!
    transactionsFromAccountByNumberRange(account: String!, from: String!, to: String!): [Transaction!]!
  
    transactionCountFromAccountByTimeRange(account: String!, from: String!, to: String!): Int!
    transactionsFromAccountByTimeRange(account: String!, from: String!, to: String!): [Transaction!]!
  
    transactionCountToAccountByNumberRange(account: String!, from: String!, to: String!): Int!
    transactionsToAccountByNumberRange(account: String!, from: String!, to: String!): [Transaction!]!

    transactionCountToAccountByTimeRange(account: String!, from: String!, to: String!): Int!
    transactionsToAccountByTimeRange(account: String!, from: String!, to: String!): [Transaction!]!

    transactionCountBetweenAccountsByNumberRange(fromAccount: String!, toAccount: String!, from: String!, to: String!): Int!
    transactionsBetweenAccountsByNumberRange(fromAccount: String!, toAccount: String!, from: String!, to: String!): [Transaction!]!

    transactionCountBetweenAccountsByTimeRange(fromAccount: String!, toAccount: String!, from: String!, to: String!): Int!
    transactionsBetweenAccountsByTimeRange(fromAccount: String!, toAccount: String!, from: String!, to: String!): [Transaction!]!

    contractsCreatedFromAccountByNumberRange(account: String!, from: String!, to: String!): [Transaction!]!
    contractsCreatedFromAccountByTimeRange(account: String!, from: String!, to: String!): [Transaction!]!
    transactionFromAccountWithNonce(account: String!, nonce: String!): Transaction!
}

Response will be of type 👇

type Transaction {
  hash: String!
  from: String!
  to: String!
  contract: String!
  value: String!
  data: String!
  gas: String!
  gasPrice: String!
  cost: String!
  nonce: String!
  state: String!
  blockHash: String!
}

Method	Parameters	Possible use case
transaction	hash: String!	When you know txHash & want to get that tx data
transactionCountByBlockHash	hash: String!	When you know block hash & want to get count of tx(s) packed in that block
transactionsByBlockHash	hash: String!	When you know block hash & want to get all tx(s) packed in that block
transactionCountByBlockNumber	number: String!	When you know block number & want to get count of tx(s) packed in that block
transactionsByBlockNumber	number: String!	When you know block number & want to get all tx(s) packed in that block
transactionCountFromAccountByNumberRange	account: String!, from: String!, to: String!	When you know tx sender address, block number range & want to find out how many tx(s) were sent by this address in that certain block number range
transactionsFromAccountByNumberRange	account: String!, from: String!, to: String!	When you know tx sender address, block number range & want to find out all tx(s) that were sent by this address in that certain block number range
transactionCountFromAccountByTimeRange	account: String!, from: String!, to: String!	When you know tx sender address, unix time stamp range & want to find out how many tx(s) were sent by this address in that certain timespan
transactionsFromAccountByTimeRange	account: String!, from: String!, to: String!	When you know tx sender address, unix time stamp range & want to find out all tx(s) that were sent by this address in that certain timespan
transactionCountToAccountByNumberRange	account: String!, from: String!, to: String!	When you know tx receiver address, block number range & want to find out how many tx(s) were sent to this address in that certain block number range
transactionsToAccountByNumberRange	account: String!, from: String!, to: String!	When you know tx receiver address, block number range & want to find out all tx(s) that were sent to this address in that certain block number range
transactionCountToAccountByTimeRange	account: String!, from: String!, to: String!	When you know tx receiver address, unix time stamp range & want to find out how many tx(s) were sent to this address in that certain timespan
transactionsToAccountByTimeRange	account: String!, from: String!, to: String!	When you know tx receiver address, unix time stamp range & want to find out all tx(s) that were sent to this address in that certain timespan
transactionCountBetweenAccountsByNumberRange	fromAccount: String!, toAccount: String!, from: String!, to: String!	When you know tx sender & receiver addresses, block number range & want to find out how many tx(s) were sent from sender to receiver in that certain block number range
transactionsBetweenAccountsByNumberRange	fromAccount: String!, toAccount: String!, from: String!, to: String!	When you know tx sender & receiver addresses, block number range & want to find out all tx(s) that were sent from sender to receiver in that certain block number range
transactionCountBetweenAccountsByTimeRange	fromAccount: String!, toAccount: String!, from: String!, to: String!	When you know tx sender & receiver addresses, unix timestamp range & want to find out how many tx(s) were sent from sender to receiver in that certain timespan
transactionsBetweenAccountsByTimeRange	fromAccount: String!, toAccount: String!, from: String!, to: String!	When you know tx sender & receiver addresses, unix timestamp range & want to find out all tx(s) that were sent from sender to receiver in that certain timespan
contractsCreatedFromAccountByNumberRange	account: String!, from: String!, to: String!	When you know EOA's ( externally owned account ) address & want to find out all contracts created by that account in block number range
contractsCreatedFromAccountByTimeRange	account: String!, from: String!, to: String!	When you know EOA's ( externally owned account ) address & want to find out all contracts created by that account in certain time span
transactionFromAccountWithNonce	account: String!, nonce: String!	When you have EOA's address & nonce value of it, you can pin point to that tx. This can be used to iterate through all tx(s) from this account, by updating nonce.

---

Historical Event Data ( GraphQL API ) 🤩

You can ask ette for event data using GraphQL API.

Path: /v1/graphql

Method: POST

type Query {
    eventsFromContractByNumberRange(contract: String!, from: String!, to: String!): [Event!]!
    eventsFromContractByTimeRange(contract: String!, from: String!, to: String!): [Event!]!
    eventsByBlockHash(hash: String!): [Event!]!
    eventsByTxHash(hash: String!): [Event!]!
    eventsFromContractWithTopicsByNumberRange(contract: String!, from: String!, to: String!, topics: [String!]!): [Event!]!
    eventsFromContractWithTopicsByTimeRange(contract: String!, from: String!, to: String!, topics: [String!]!): [Event!]!
    lastXEventsFromContract(contract: String!, x: Int!): [Event!]!
    eventByBlockHashAndLogIndex(hash: String!, index: String!): Event!
    eventByBlockNumberAndLogIndex(number: String!, index: String!): Event!
}

Response will be of type 👇

type Event {
  origin: String!
  index: String!
  topics: [String!]!
  data: String!
  txHash: String!
  blockHash: String!
}

Method	Parameters	Possible use case
eventsFromContractByNumberRange	contract: String!, from: String!, to: String!	When you've one contract address, block number range & you want to find out all events emitted by that contract in given block range
eventsFromContractByTimeRange	contract: String!, from: String!, to: String!	When you know contract address, unix time stamp range & you want to find out all events emitted by that contract in given timespan
eventsByBlockHash	hash: String!	When you've block hash & want to find out all events emitted in tx(s) packed in that block
eventsByTxHash	hash: String!	When you've txHash & want to find out all events emitted during execution of that tx
eventsFromContractWithTopicsByNumberRange	contract: String!, from: String!, to: String!, topics: [String!]!	When you've smart contract address, block number range & an ordered list of event log's topic signature(s), you can find out all events emitted by that contract with specific signature(s) in block range
eventsFromContractWithTopicsByTimeRange	contract: String!, from: String!, to: String!, topics: [String!]!	When you've smart contract address, unix time stamp range & an ordered list of event log's topic signature(s), you can find out all events emitted by that contract with specific signature(s) in given timespan
lastXEventsFromContract	contract: String!, x: Int!	When you know just contract address & want to find out last X events emitted by that contract [ Very useful sometimes 😅 ]
eventByBlockHashAndLogIndex	hash: String!, index: String!	When you know block hash, index of event log in block & want to get back specific event in that position
eventByBlockHashAndLogIndex	number: String!, index: String!	When you know block number, index of event log in block & want to get back specific event in that position

---

Browser based GraphQL Playground : /v1/graphql-playground 👇🤩

---

Real time notification for mined blocks ⛏

For listening to blocks getting mined, connect to /v1/ws endpoint using websocket client library & once connected, you need to send subscription request with 👇 payload ( JSON encoded )

{
    "name": "block",
    "type": "subscribe",
    "apiKey": "0x..."
}

If everything goes fine, your subscription will be confirmed with 👇 response ( JSON encoded )

{
    "code": 1,
    "message": "Subscribed to `block`"
}

After that as long as your machine is reachable, ette will keep notifying you about new blocks getting mined in 👇 form

{
  "hash": "0x08f50b4795667528f6c0fdda31a0d270aae60dbe7bc4ea950ae1f71aaa01eabc",
  "number": 7015086,
  "time": 1605328635,
  "parentHash": "0x5ec0faff8b48e201e366a3f6c505eb274904e034c1565da2241f1327e9bad459",
  "difficulty": "6",
  "gasUsed": 78746,
  "gasLimit": 20000000,
  "nonce": 0,
  "miner": "0x0000000000000000000000000000000000000000",
  "size": 1044,
  "txRootHash": "0x088d6142b1d79803c851b1d839888b1e9f26c31e1266b4e221121f2cd8e85f86",
  "receiptRootHash": "0xca3949d52f113935ac08bae15e0816cd0472f01590f0fe0b65584bfb3aa324a6"
}

If you want to cancel subscription, consider sending 👇

{
    "name": "block",
    "type": "unsubscribe",
    "apiKey": "0x..."
}

You'll receive 👇 response, confirming unsubscription

{
    "code": 1,
    "message": "Unsubscribed from `block`"
}

Sample code can be found here

Real time notification for transactions ⚡️

For listening to any transaction happening in network in real-time, send 👇 JSON encoded payload to /v1/ws

{
    "name": "transaction/<from-address>/<to-address>",
    "type": "subscribe",
    "apiKey": "0x..."
}

Here we've some examples :

• Any transaction

{
    "name": "transaction/*/*",
    "type": "subscribe",
    "apiKey": "0x..."
}

Sample Code can be found here

• Fixed from field [ tx originated from account ]

{
    "name": "transaction/0x4774fEd3f2838f504006BE53155cA9cbDDEe9f0c/*",
    "type": "subscribe",
    "apiKey": "0x..."
}

Sample Code can be found here

• Fixed to field [ tx targeted to account ]

{
    "name": "transaction/*/0x4774fEd3f2838f504006BE53155cA9cbDDEe9f0c",
    "type": "subscribe",
    "apiKey": "0x..."
}

Sample Code can be found here

• Fixed from & to field [ tx from -> to account ]

{
    "name": "transaction/0xc9D50e0a571aDd06C7D5f1452DcE2F523FB711a1/0x4774fEd3f2838f504006BE53155cA9cbDDEe9f0c",
    "type": "subscribe",
    "apiKey": "0x..."
}

Sample Code can be found here

If everything goes fine, your subscription will be confirmed with 👇 response ( JSON encoded )

{
    "code": 1,
    "message": "Subscribed to `transaction`",
    "apiKey": "0x..."
}

After that as long as your machine is reachable, ette will keep notifying you about every transaction happening in 👇 form, where criterias matching

{
  "hash": "0x08cfda79bd68ad280c7786e5dd349ab81981c52ea5cdd8e31be0a4b54b976555",
  "from": "0xc9D50e0a571aDd06C7D5f1452DcE2F523FB711a1",
  "to": "0x4774fEd3f2838f504006BE53155cA9cbDDEe9f0c",
  "contract": "",
  "value": "",
  "data": "0x35086d290000000000000000000000000000000000000000000000000000000000000360",
  "gas": 200000,
  "gasPrice": "1000000000",
  "cost": "200000000000000",
  "nonce": 19899,
  "state": 1,
  "blockHash": "0xc29170d33141602a95b915c954c1068a380ef5169178eef2538beb6edb005810"
}

If you want to cancel subscription, consider sending 👇, while replacing <from-address> & <to-address> with specific addresses you used when subscribing.

{
    "name": "transaction/<from-address>/<to-address>",
    "type": "unsubscribe",
    "apiKey": "0x..."
}

You'll receive 👇 response, confirming unsubscription

{
    "code": 1,
    "message": "Unsubscribed from `transaction`"
}

Real-time notification for events 📧

For listening to any events getting emitted by smart contracts deployed on network, you need to send 👇 JSON encoded payload to /v1/ws endpoint, after connecting over websocket

{
    "name": "event/<contract-address>/<topic-0-signature>/<topic-1-signature>/<topic-2-signature>/<topic-3-signature>",
    "type": "subscribe",
    "apiKey": "0x..."
}

Here we've some examples :

• Any event emitted by any smart contract in network

{
    "name": "event/*/*/*/*/*",
    "type": "subscribe",
    "apiKey": "0x..."
}

• Any event emitted by one specific smart contract

{
    "name": "event/0xcb3fA413B23b12E402Cfcd8FA120f983FB70d8E8/*/*/*/*",
    "type": "subscribe",
    "apiKey": "0x..."
}

• Specific event emitted by one specific smart contract

{
    "name": "event/0xcb3fA413B23b12E402Cfcd8FA120f983FB70d8E8/0x2ab93f65628379309f36cb125e90d7c902454a545c4f8b8cb0794af75c24b807/*/*/*",
    "type": "subscribe",
    "apiKey": "0x..."
}

• Specific event emitted by any smart contract in network

{
    "name": "event/*/0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef/*/*/*",
    "type": "subscribe",
    "apiKey": "0x..."
}

Sample code can be found here

If everything goes fine, your subscription will be confirmed with 👇 JSON encoded response

{
    "code": 1,
    "message": "Subscribed to `event`"
}

After that as long as your machine is reachable, ette will keep notifying you about every event emitted by smart contracts, to which you've subscribed to, in 👇 format

{
  "origin": "0x0000000000000000000000000000000000001010",
  "index": 3,
  "topics": [
    "0x4dfe1bbbcf077ddc3e01291eea2d5c70c2b422b415d95645b9adcfd678cb1d63",
    "0x0000000000000000000000000000000000000000000000000000000000001010",
    "0x0000000000000000000000004d31abd8533c00436b2145795cc4cef207c3364f",
    "0x00000000000000000000000042eefcda06ead475cde3731b8eb138e88cd0bac3"
  ],
  "data": "0x0000000000000000000000000000000000000000000000000000454b2247e2000000000000000000000000000000000000000000000000001a96ae0b49dfc60000000000000000000000000000000000000000000000003a0df005a45c3dd5dd0000000000000000000000000000000000000000000000001a9668c02797e40000000000000000000000000000000000000000000000003a0df04aef7e85b7dd",
  "txHash": "0xfdc5a29fdd57a53953a542f4c46b0ece5423227f26b1191e58d32973b4d81dc9",
  "blockHash": "0x08e9ac45e4041a4309c6f5dd42b0fc78e00ca0cb8603965465206b22a63d07fb"
}

If you want to cancel subscription, consider sending 👇, while replacing <contract-address>, <topic-{0,1,2,3}-signature> with specific values you used when subscribing.

{
    "name": "event/<contract-address>/<topic-0-signature>/<topic-1-signature>/<topic-2-signature>/<topic-3-signature>",
    "type": "unsubscribe",
    "apiKey": "0x..."
}

You'll receive 👇 response, confirming unsubscription

{
    "code": 1,
    "message": "Unsubscribed from `event`"
}

Note: If graceful unsubscription not done, when ette finds client unreachable, it'll remove client subscription

Take snapshot of existing data store ➡️

Assuming you've already a running instance of ette for some EVM compatible chain, you can always attempt to take snapshot of whole backing data store, so that if you need to spin up another instance of ette, you won't require to sync whole chain data, rather you use this binary data file, which can be used by ette for restoring from snapshot data.

Setting EtteMode = 4, attempts to take snapshot of DB.

Restore data from snapshot ⬅️

Once you've snapshotted binary encoded data file, you can attempt to restore from this & rebuild whole data store, with out syncing whole chain data. EtteMode = 5, attempts to do 👇.

Once that's done, consider restarting ette in desired mode so that it can keep itself in sync with latest chain happenings.

More coming soon