An efficient re-implementation of Electrum Server in Rust

[romanzeyde]

Hello all,

I was working on this project for the last few months, so a user could run his own Electrum server, with required hardware resources not much beyond those of a full node (using ideas from ElectrumX [1], Electrum Personal Server [2] and bitcoincore-indexd [3]).

The code and usage instructions can be found here:
https://github.com/romanz/electrs

The server indexes the entire Bitcoin blockchain, and the resulting index [4] enables fast queries for any given user wallet, allowing the user to keep real-time track of his balances and his transaction history using the Electrum wallet [5].
Since it runs on the user's own machine, there is no need for the wallet to communicate with external Electrum servers, thus preserving the privacy of the user's addresses and balances.

Features:
 * Supports latest Electrum protocol [6].
 * Maintains an index of transaction inputs and outputs, allowing fast balance queries
 * Fast synchronization of the Bitcoin blockchain (~2.5 hours for ~185GB @ June 2018) on modest hardware [7]
 * Low CPU & memory usage (after initial indexing)
 * Low index storage overhead (~20%), relying on a local full node for transaction retrieval
 * Efficient mempool tracker allowing better fee estimation [8].
 * `-txindex` is not required for the Bitcoin node
 * Uses `rust-bitcoin` library [9] for efficient serialization/deserialization of Bitcoin transactions
 * Uses a single RocksDB [10] database, for better consistency and crash recovery

Hope you'll find it useful
Questions, suggestions and pull requests are welcome!

[1] https://github.com/kyuupichan/electrumx
[2] https://github.com/chris-belcher/electrum-personal-server
[3] https://github.com/jonasschnelli/bitcoincore-indexd
[4] https://github.com/romanz/electrs/blob/master/doc/schema.md
[5] https://electrum.org
[6] https://electrumx.readthedocs.io/en/latest/protocol.html
[7] https://gist.github.com/romanz/cd9324474de0c2f121198afe3d063548
[8] https://github.com/spesmilo/electrum/blob/59c1d03f018026ac301c4e74facfc64da8ae4708/RELEASE-NOTES#L34-L46)
[9] https://github.com/rust-bitcoin/rust-bitcoin
[10] https://github.com/spacejam/rust-rocksdb

[ThatRandom8543]

Hello all,

I was working on this project for the last few months, so a user could run his own Electrum server, with required hardware resources not much beyond those of a full node (using ideas from ElectrumX [1], Electrum Personal Server [2] and bitcoincore-indexd [3]).

The code and usage instructions can be found here:
https://github.com/romanz/electrs

The server indexes the entire Bitcoin blockchain, and the resulting index [4] enables fast queries for any given user wallet, allowing the user to keep real-time track of his balances and his transaction history using the Electrum wallet [5].
Since it runs on the user's own machine, there is no need for the wallet to communicate with external Electrum servers, thus preserving the privacy of the user's addresses and balances.

Features:
 * Supports latest Electrum protocol [6].
 * Maintains an index of transaction inputs and outputs, allowing fast balance queries
 * Fast synchronization of the Bitcoin blockchain (~2.5 hours for ~185GB @ June 2018) on modest hardware [7]
 * Low CPU & memory usage (after initial indexing)
 * Low index storage overhead (~20%), relying on a local full node for transaction retrieval
 * Efficient mempool tracker allowing better fee estimation [8].
 * `-txindex` is not required for the Bitcoin node
 * Uses `rust-bitcoin` library [9] for efficient serialization/deserialization of Bitcoin transactions
 * Uses a single RocksDB [10] database, for better consistency and crash recovery

Hope you'll find it useful
Questions, suggestions and pull requests are welcome!

[1] https://github.com/kyuupichan/electrumx
[2] https://github.com/chris-belcher/electrum-personal-server
[3] https://github.com/jonasschnelli/bitcoincore-indexd
[4] https://github.com/romanz/electrs/blob/master/doc/schema.md
[5] https://electrum.org
[6] https://electrumx.readthedocs.io/en/latest/protocol.html
[7] https://gist.github.com/romanz/cd9324474de0c2f121198afe3d063548
[8] https://github.com/spesmilo/electrum/blob/59c1d03f018026ac301c4e74facfc64da8ae4708/RELEASE-NOTES#L34-L46)
[9] https://github.com/rust-bitcoin/rust-bitcoin
[10] https://github.com/spacejam/rust-rocksdb

About a year ago, I attempted to redo electrum in rust (mainly the server side of it) mainly to push away from using python on a server, and to create something that would have high performance while remaining scalable, secured and have a low footprint.  Decided to move to a different route than to re-implement it, but I will say you got WAY further than me. Even though you do have a TODO list, one thing I will suggest though is that you list the limitations of your implementation so others, if not you, can improve on it as it grows.

[romanzeyde]

Thanks for the compliment

I will suggest though is that you list the limitations of your implementation so others, if not you, can improve on it as it grows.

Good point, will add a document for that!

N.B.
https://github.com/romanz/electrs/issues/8

[HCP]

Before anyone asks... you use --daemon-dir to specify your custom Bitcoin directory location

All commandline args are listed here: https://github.com/romanz/electrs/blob/master/src/config.rs

I'm currently attempting to see if this will work on Ubuntu 16.04 running on the Windows Linux Subsystem... combined with Bitcoin Core running under Windows. I'll update how I get on.

[romanzeyde]

I'll update how I get on.

Thanks a lot!
Please let me know if there are any issues/problems

[HCP]

Has been slow going... My router died the other day and after a day of being bounced around various departments at my ISP to get a replacement, a friend loaned me one and I managed to get back online...

Since then the various Ubuntu and Rust repositories have been spitting out random errors... So I think my connection still isn't quite right.

I think I finally managed to get it all synced up and set it compiling before heading to work... Will check it after my shift


EDIT: ok, so I managed to get it compiled and running and it is picking up new blocks:

Code:

2018-07-20T19:36:14.665+12:00 - DEBUG - Server listening on 127.0.0.1:42024
2018-07-20T19:36:14.669+12:00 - DEBUG - Running accept thread
2018-07-20T19:36:14.682+12:00 - DEBUG - BlockchainInfo { chain: "main", blocks: 532757, headers: 532757, bestblockhash: "00000000000000000021489dbeba2486cb06231787a01248d5279b478d44d29d", size_on_disk: 199680846175, pruned: false }
2018-07-20T19:36:14.684+12:00 - DEBUG - NetworkInfo { version: 160100, subversion: "/Satoshi:0.16.1/" }
2018-07-20T19:36:14.684+12:00 - DEBUG - opening DB at "/mnt/s/db/mainnet"
2018-07-20T19:36:15.476+12:00 - INFO - listing block files at "/mnt/e/Bitcoin/blocks/blk*.dat"
2018-07-20T19:36:15.504+12:00 - INFO - indexing 1321 blk*.dat files
2018-07-20T19:37:08.956+12:00 - DEBUG - applying 532758 new headers from height 0
2018-07-20T20:07:53.198+12:00 - DEBUG - skipping block 000000000000000001b982e5989a72cd799130f71cf3acd6db6214de024a8ad2
2018-07-20T20:07:53.669+12:00 - DEBUG - skipping block 000000000000000000352b9ad3494acf88b0aa73a4c6f8987bab247e6c32d9ca
2018-07-20T20:08:13.935+12:00 - DEBUG - skipping block 0000000000000000009085be97279a7ab4d20e983be9cb20fe0c2e0d49313cdd
...
snip Bunch of "DEBUG - skipping block lines"
...
2018-07-20T20:28:43.430+12:00 - DEBUG - no more blocks to index
2018-07-20T20:28:44.543+12:00 - DEBUG - last indexed block: best=00000000000000000021489dbeba2486cb06231787a01248d5279b478d44d29d height=532757 @ 2018-07-20T07:32:29Z
2018-07-20T20:28:44.774+12:00 - INFO - starting full compaction
2018-07-20T21:38:04.565+12:00 - INFO - finished full compaction
2018-07-20T21:38:09.008+12:00 - DEBUG - applying 532758 new headers from height 0
2018-07-20T21:38:09.518+12:00 - DEBUG - downloading new block headers (532758 already indexed) from 0000000000000000000dc8a8b42d286c1796337a3cc44622143320e98a40415c
2018-07-20T21:38:09.539+12:00 - INFO - best=0000000000000000000dc8a8b42d286c1796337a3cc44622143320e98a40415c height=532779 @ 2018-07-20T09:26:49Z (22 left to index)
2018-07-20T21:38:13.016+12:00 - DEBUG - applying 22 new headers from height 532758
2018-07-20T21:38:13.822+12:00 - INFO - RPC server running on 127.0.0.1:50001
2018-07-20T21:55:05.336+12:00 - DEBUG - downloading new block headers (532780 already indexed) from 00000000000000000003972c3d95015978a4b7fa5662aee1417b677058178318
2018-07-20T21:55:05.338+12:00 - INFO - best=00000000000000000003972c3d95015978a4b7fa5662aee1417b677058178318 height=532780 @ 2018-07-20T09:54:40Z (1 left to index)
2018-07-20T21:55:06.067+12:00 - DEBUG - applying 1 new headers from height 532780

However, when I attempt to connect with Electrum (v3.2.2)... it starts generating "UTF8" errors

Code:

2018-07-20T23:40:28.775+12:00 - INFO - [127.0.0.1:61899] connected peer
2018-07-20T23:40:28.783+12:00 - INFO - [127.0.0.1:61899] shutting down connection
2018-07-20T23:40:28.783+12:00 - ERROR - [127.0.0.1:61899] receiver failed: invalid UTF8 "\u{16}\u{3}\u{1}\u{2}\u{0}\u{1}\u{0}[b][REDACTED][/b]\n": FromUtf8Error { bytes: [22, 3, 1, 2, 0, 1, 0, [b][REDACTED][/b]], error: Utf8Error { valid_up_to: 8, error_len: Some(1) } }
2018-07-20T23:40:28.786+12:00 - INFO - [127.0.0.1:61900] connected peer
2018-07-20T23:40:28.786+12:00 - INFO - [127.0.0.1:61899] disconnected peer
2018-07-20T23:40:28.792+12:00 - INFO - [127.0.0.1:61900] shutting down connection
2018-07-20T23:40:28.793+12:00 - ERROR - [127.0.0.1:61900] receiver failed: invalid UTF8 "\u{16}\u{3}\u{1}\u{2}\u{0}\u{1}\u{0}[b][REDACTED][/b]\n": FromUtf8Error { bytes: [22, 3, 1, 2, 0, 1, 0, [b][REDACTED][/b]], error: Utf8Error { valid_up_to: 8, error_len: Some(1) } }
2018-07-20T23:40:28.794+12:00 - INFO - [127.0.0.1:61900] disconnected peer

Any ideas? NOTE: also created an issue on GitHub


EDIT2: as per the note on Github... it is related to SSL connections... currently there is no way to disable SSL in the GUI... but starting Electrum and forcing to use TCP with the following command:

Code:

"C:\Program Files (x86)\Electrum\electrum-3.2.2.exe" --server=127.0.0.1:50001:t

And it all connects and syncs up... pretty happy to have my own Electrum server now

[romanzeyde]

Cool, glad to hear that it works

[HCP]

I guess the lack of SSL isn't a "big deal", since I'm connecting to localhost... but are you planning on implementing SSL in case I'd like to host it on a separate/remote box?

[romanzeyde]

Sorry for the delayed response - you can use a TLS-terminating proxy (such as https://hitch-tls.org/).
See https://github.com/romanz/electrs/commit/288cda518c3df6d49ed6d27fcd8f9f10d69a84cd#diff-9d70860c70981206f00c69a429b69ad1.

[elebit]

Interesting project! Electrum server could certainly be improved on.

Is this software for running a personal server or could it be used to run a public server?

How well would it handle the load of thousands simultaneous users, asking for many addresses each?

[romanzeyde]

Thanks!
This project was designed for personal use (e.g. optimized for HDD, no DoS prevention mechanisms).

Currently, it doesn't utilize SSD for better performance (so it would be hard to support thousands users), but there is a WIP branch for a new (more SSD-friendly) indexing schema here:
https://github.com/romanz/electrs/commits/new-index

[hashslinger]

Which full node implementations of bitcoin and bitcoin* cash are compatible with this Electrum server? I tried Parity, so that I could run bitcoin and bitcoin cash while only having to upgrade one codebase.  However, ElectrumX will not speak to Parity. From my perspective, Parity and bitcoin core follow the same network protocol, but within my localhost they use a different database formats.  Hence why ElectrumX rejects Parity's RPC responses with:

Code:

 
Jan 30 05:55:12  electrumx_server[4937]: ERROR:root:task crashed: <Task finished coro=<Controller.serve() done, defined at /usr/local/lib/python3.7/dist-packages/electrumX-1.8.12-py3.7.egg/electrumx
Jan 30 05:55:12  electrumx_server[4937]: Traceback (most recent call last):
Jan 30 05:55:12  electrumx_server[4937]:   File "/home/electrum/.local/lib/python3.7/site-packages/aiorpcx/util.py", line 118, in
.
.

Jan 30 05:55:12  electrumx_server[4937]: ERROR:Daemon:Supplied content type is not allowed. Content-Type: application/json is required

I didn't see any specs for the full node implementation compatibility on either https://github.com/romanz/electrs/blob/master/doc/usage.md or https://github.com/kyuupichan/electrumx/tree/master/docs . Also, is there a way to run one full node implementation Thanks for reading.

*I use lower case to denote that I am referring to the bitcoin/bitcoin cash networks and not the units of account.

[romanzeyde]

It should work with latest Bitcoin Core (0.16+).
Didn't test with Parity or with Bitcoin Cash nodes...

[AussieHash]

What would you recommend are the steps to update to the newest release v0.7 (in my case I have v0.62 from early June) ?
I have not made any local changes to the code.

Code:

$ git clone https://github.com/romanz/electrs
$ cd electrs
$ git fetch origin
$ git status
$ git pull
$ cargo build --release

[romanzeyde]

The underlying storage format didn't change, so the instructions above should work

[AussieHash]

Thank you, the update went smoothly.  The Cargo build only took 45 seconds or so.

[MrNayda]

"Before anyone asks... you use --daemon-dir to specify your custom Bitcoin directory location "

Where do you specify this exactly? I'm an Ubuntu / Linux noob trying to set up Electrum Rust using laptop + external HDD, & have run into a problem I can't seem to solve -

Node is synced to the tip & fully indexed, with blocks & data stored on external HDD, while bitcoin.conf & .cookie files appear in .bitcoin folder in Home directory. However in my first Electrum Rust "usage" ie. index sync ($ cargo run --release -- -vvv --timestamp --db-dir ./db --electrum-rpc-addr="127.0.0.1:50001"), as per the "Usage" section (https://github.com/romanz/electrs/blob/master/doc/usage.md) I get the following error -


"2020-03-02T16:09:42.188+10:30 - INFO - indexing 0 blk*.dat files
2020-03-02T16:09:42.189+10:30 - DEBUG - found 0 indexed blocks
2020-03-02T16:10:03.639+10:30 - DEBUG - applying 619796 new headers from height 0

thread 'bulk_writer' panicked at 'no indexed header found', src/libcore/option.rs:1188:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
thread 'main' panicked at 'writer panicked: Any', src/libcore/result.rs:1188:5"

My data directory is on my external HDD, however it appears Electrs is looking for blocks in the default directory?

Any help would be very much appreciated!

[HCP]

Ok... so I use a shell script to start it up... it's basically one line:

Code:

cargo run --release -- -vvv --timestamp --db-dir /mnt/e/electrs --daemon-dir /mnt/e/Bitcoin --electrum-rpc-addr="127.0.0.1:50001"

As you can see... I've got --daemon-dir added into the "cargo run" command... and specified the path to my Bitcoin blocks folder... "/mnt/e/Bitcoin" (I've also put the electrs db-dir in a custom location too)

[MrNayda]

Ok... so I use a shell script to start it up... it's basically one line:

Code:

cargo run --release -- -vvv --timestamp --db-dir /mnt/e/electrs --daemon-dir /mnt/e/Bitcoin --electrum-rpc-addr="127.0.0.1:50001"

As you can see... I've got --daemon-dir added into the "cargo run" command... and specified the path to my Bitcoin blocks folder... "/mnt/e/Bitcoin" (I've also put the electrs db-dir in a custom location too)

Great, thank you for suggesting! Doesn't seem to do the trick unfortunately. I assume that   --db-dir ./db  within the argument refers to the Electrum database, so I've left this unchanged given I have Electrs located in the default /home/electrs/ location. Thus my code is as follows -

Code:

cargo run --release -- -vvv --timestamp --db-dir ./db --daemon-dir /mnt/HDD/ --electrum-rpc-addr="127.0.0.1:50001"

This returns the following recurring error:

"WARN - reconnecting to bitcoind: failed to read cookie from /mnt/HDD/.cookie"
.
The .cookie file is not produced within the /mnt/HDD/ folder but instead within /Home/User/.bitcoin, together with the bitcoin.conf file, & I have the following argument within the bitcoin.conf file that sets /mnt/HDD/ as the data directory: "datadir=/mnt/HDD"

I have the following argument - "rpccookiefile=/home/user/.bitcoin/.cookie" - within the bitcoin.conf file to create the .cookie file there so that Bitcoind will run from the default /Home/User/.bitcoin directory but use the /mnt/HDD to store the blocks.

I've tried setting /Home/User/.bitcoin as the --daemon-dir in your suggested argument however this returned the original error, where Electrs appears to look for blocks within /Home/User/.bitcoin instead of /mnt/HDD.

Hope this makes sense, very new to Ubuntu/Linux & setting up a node etc. How to proceed from here?

Thank you in advance!

[HCP]

Great, thank you for suggesting! Doesn't seem to do the trick unfortunately. I assume that   --db-dir ./db  within the argument refers to the Electrum database, so I've left this unchanged given I have Electrs located in the default /home/electrs/ location.

Did you mean Electrum database... or electrs database? db-dir is the location where electrs stores it's database.

The .cookie file is not produced within the /mnt/HDD/ folder but instead within /Home/User/.bitcoin, together with the bitcoin.conf file, & I have the following argument within the bitcoin.conf file that sets /mnt/HDD/ as the data directory: "datadir=/mnt/HDD"

I have the following argument - "rpccookiefile=/home/user/.bitcoin/.cookie" - within the bitcoin.conf file to create the .cookie file there so that Bitcoind will run from the default /Home/User/.bitcoin directory but use the /mnt/HDD to store the blocks.

Ahhh ok, yeah... you've added an extra layer of complexity by moving some of the Bitcoin data to your /mnt/HDD location, but then leaving some of it in the default "/home/user/.bitcoin" location.

By default, electrs simply looks for the cookie in the daemon-dir... If you have the cookie in a custom location, you'd need to specify that. There is a cookie-file argument that you can use for this.

So, try this:

Code:

cargo run --release -- -vvv --timestamp --db-dir ./db --daemon-dir /mnt/HDD/ --electrum-rpc-addr="127.0.0.1:50001" --cookie-file /home/user/.bitcoin/.cookie