Stories from the dev front (memoir)


So we thought about starting short catapult related thread here.

Don’t expect constant or frequent updates, just some random msgs from us.

18th May 2018

If you somehow haven’t heard yet, we’ve published some initial version of both
catapult-server and catapult-rest.
Catapult-rest also has npm packages:

Mind that current version is not ready yet, to run public chain.

There are some precompiled docker images, but we’re waiting for some fireworks from TB, that will allow setting up network with a single click.

As you might have noticed I don’t update this thread so much, but I tweet from time to time.

28th Mar 2018

As mentioned of twitter, around 2 weeks ago we’ve slowly started next milestone (bison). 2 out of 3 parts of this milestone that we’ve already started are time synchronization and important memory optimizations, that are necessary to run public chain (we’ve barely started experiments, we’ll know bit more after that).

7th Feb 2018

We’re getting close to completing next milestone (alpaca). We’ve added two types of new lock transactions (if you’re asking, they are needed, but we reveal more details at some later point). Second part of the milestone is network discovery which is crucial for public network.
We’re slowly beginning to test the changes, and guys are adding support to new txes on sdk side.

12th Dec 2017

Just to keep you updated, some time ago @Jaguar0625 made some more order in our tasks, splitting them into alpha, and beta we’ve been trying to pay technical debt, here are some nice graphs for you with burnup rates
(tasks opened/closed)


P.S. I bet there’s someone, who can try to nicely align them with some level of transparency ^^

1st Nov 2017

Long time, no hear, we actually had partial collector working for some time already. In the meantime issues has arisen, how to pass some of partial transaction related data to client apps. That’s more or less what we are pursuing now.
We’ve also found and fixed some bugs, @aleix_mp and @guillem have prepared e2e tests, are up to date with catapult-based low-level bindings for multiple languages that we’ll refer to as nem2-library.

1st Sep 2017

So it seems we’ve managed to finished failed transaction status collecting (that’s something that we needed, since transaction processing is a bit different in catapult, and there’s much more asynchronicity). Next thing on our list is so called “cosignatures collector” - this will be part of api server. More on that will probably be #soon in a separate post.
Also if you haven’t I post some shorter messages on twitter.

09th Aug 2017

We got basic support for websockets. We’re using ZMQ to pump data from api server to zmq endpoint where rest server listens. We should be able to do some testing of wallet supporting websockets this week.
In the meantime there were quite big internal changes when it comes to structure, thanks to this we’ll be able (in future) to change p2p and api servers just by switching some options – turning on and off some extensions.

25th Jun 2017

We’ve sort of finished secret feature and we’ve prepared deployment of an internal test network (shown to very limited group of people). Before we’ll be able to show it to a larger audience, we need websockets support (you don’t want to refresh wallet every time). That’s not as easy as it sounds as we have few competing ideas how to do it.

30th May 2017

Dear diary, I’ve missed the fact that we’ve hit 900 reviews, our latest has actually number 910.
We currently have over 7400 commits (excluding merges), gross of that belongs to Jaguar0625.
(number itself is actually bit higher as we sometimes squash the changes).

23th May 2017

Don’t have anything interesting to share, we were trying to reduce tech debt, it’s clearly visible on a burnup rate graph

Jaguar made huge changes how validators and observers (think of it as transaction executors) work.
We slowly started working on multisig transactions, that part will be bit complicated (due to changes we’ve planned, and due to architecture changes), we will try to share some more details in future.

6th Apr 2017

We have some basic support for mosaics, although we don’t have levies yet. There will be some interesting changes regarding mosaics, although most likely they will be invisible from end user perspective.
Long time since I’ve pasted any cloc stats, so let’s go :slight_smile:

SRC (including tools)

 Language                     files          blank        comment           code
C++                            266           3414            596          15439
C/C++ Header                   420           4077           3420          13752
CMake                           43             54              7            193
SUM:                           729           7545           4023          29384


Language                     files          blank        comment           code
C++                            392          13402           9529          46586
C/C++ Header                   105           1789           1576           6228
CMake                           47             62              1            193
SUM:                           544          15253          11106          53007

total number of tests: ~4975

9th Mar 2017

We’ve added namespaces, and we were doing some initial tests of namespaces, we hope we’ll be able to wrap them up and start working on mosaics.

10th Feb 2017

Nothing fancy to report, we had some big structural changes due to plugins, @BloodyRookie did some heavy lifting of api node transation storage, both J and BR fixed some problems indicated in stress tests (IIRC, all problems were inside tests not inside the code), first plugin (transfer transaction) seems to be working.

We want catapult to have pluggable architecture, where one will be able to pick transaction types that are needed inside the network.

as a bonus burnup continuation of a previous graph

27th Jan 2017

This week we’ve started working on pluggable infrastructure and namespaces support.

10th Jan 2017

One of us (tip: not me ^^) has recently been busy with burning some tasks that accumulated

17th Dec

Just some testing before end of year

6th Dec

We have working e2e system (p2p nodes, api nodes, rest server).
We’ve started testing it. Obviously there are things that need fixing, but it’s pretty amazing everything
worked without much hiccup. Time spend on doing tests definitely paid of.
(obviously we’ll need much more testing, but it’s really good feeling)

We’ve also started adding websocket support to the rest server, so that we’ll be able to use nanowallet.

(we’re over 530 reviews, 2400 builds, 3800 tests, 260 rest server builds, 400 rest server tests)

24th Nov

I haven’t mentioned this earlier, but our architecture changed a bit. There will be 3 elements:

  • P2P nodes - forming the backbone of the blockchain
  • API nodes - similar to p2p nodes, but has different storage backend and it won’t take part in creation of the blockchain. It will save data for use in rest server
  • REST server - to handle json api (client requests)

We’ve hit over 500 reviews. We’ve split rest part from api/p2p node part. We’d like to start testing using rest server

4th Nov

So we are “few” hundred builds later and almost 1000 more tests.
Our plans have changed a bit and for the last 3+ weeks we’ve been working on C++ part of api server.

14th Oct

We spent some time doing research work how to proceed with an API server.
Our current plan (and approach) is that api server will be running on top of node.js
(and will communicate with p2p nodes).
We started some basic work on the api server, more details #soonish.
In case you’re wondering “why nodejs?” - main purpose of api server is well - to serve APIs :wink: so it’s generally good idea to reuse some existing server (we could have gone with ruby or with go, or put-your-favourite-platform-here, but since lightwallet and nanowallet are in JS, we will be able to share/reuse some of already existing code.

25th Sep

some spamming ahead

2nd Sep


Language                     files          blank        comment           code
C++                            131           1909            355           8759
C/C++ Header                   213           2268           1908           7897
CMake                           19             20              0             91
SUM:                           363           4197           2263          16747


Language                     files          blank        comment           code
C++                            227           7720           5501          28577
C/C++ Header                    60           1163            888           4159
CMake                           24             26              0            108
SUM:                           311           8909           6389          32844

23rd Aug


Language                     files          blank        comment           code
C++                            124           1793            342           8274
C/C++ Header                   203           2207           1846           7703
CMake                           19             20              0             91
SUM:                           346           4020           2188          16068


Language                     files          blank        comment           code
C++                            218           7307           5233          27191
C/C++ Header                    56           1091            840           3881
CMake                           24             26              0            108
SUM:                           298           8424           6073          31180

Our current number of tests is 3444

11th Aug

Some cool images for you from jenkins

bottom axis is build number

red ones are failed build (yeah that happens, as we’re using clang and VS, and build machine is using g++)

4th Aug

Today we have reached magic number of 256 reviews made.

3rd Aug

Updated code stats


Language                     files          blank        comment           code
C++                            115           1532            275           7062
C/C++ Header                   182           1990           1652           6892
CMake                           18             19              0             87
SUM:                           315           3541           1927          14041


Language                     files          blank        comment           code
C++                            199           6187           4545          23405
C/C++ Header                    49            951            725           3308
CMake                           23             25              0            108
SUM:                           271           7163           5270          26821

Our current number of tests is 3137

27th Jul

We’ve recently switched build machine, on old one we’ve come to 2493 builds.
New one is now at build 75.

Our current number of tests is 2750 (more detailed stats some time later)

Some of you might have seen the image that we’ve leaked that shows catapult dependency graph

Over and out

10th Jun


Language                     files          blank        comment           code
C/C++ Header                   131           1329           1040           4594
C++                             80            920            134           4206
CMake                           13             15              0             63
SUM:                           224           2264           1174           8863


Language                     files          blank        comment           code
C++                            140           3910           3010          14838
C/C++ Header                    36            484            308           1824
CMake                           14             17              0             64
SUM:                           190           4411           3318          16726

NEM Development stalled?
Status of Project Catapult
Status of Project Catapult
Development updates
Дневник разработчика Catapult
Github is quiet
2017 NEM Link List
The lack of information is becoming disturbing
Дневник разработчика Catapult

I like the number of tests. Are that all unit tests?
Or do you also use other kind of tests?


unit tests and more complex test, integration tests


Great to see regular updates ! :+1:


x2 speed plz :slight_smile:


what’s mean of tests number and files?


In src there’s usually single class and/or utilities in a single file. You want to have unit tests covering them, so number of test files should correlate to number of source files (i.e. number of test files should be >= number of source files). In our case it’s higher due to few things:

  • some things are in headers only (i.e. interfaces, templates) – that’s why number of headers in src is larger than number of files (124 vs 203) – you want to test them as well
  • tests, usually require some utility functions/classes, which we have separated – since tests on their own do not require separate header files, you can estimate, that number of files with utility functions/classes is 56, therefore (estimated) number of test files would be around ~162 = (218 - 56)
  • as mentioned earlier by bloodyrookie, we also have integration tests

I’ll see if I can come up with some stats, how many classes do we have and how many classes are tested, but our coverage is pretty good.


thx for the explanation. :+1:


those explanation is very useful :clap:


from these files/stats/tests are you able to give a rough % done on Catapult?

For example you expect code SUM ~ 35,000 when complete. so 50% done atm?


not really possible to do that. current state would be like this:

we have working network with basic transactions, but we need:

  • find and fix bugs
  • api layer (catapult will have multi layer approach)
  • support for all the transaction types


It can be concluded that the design follows the latest industry standard practice of aggregating and abstracting the APIs into a separate layer providing better maintainability, efficiency and service.

In trying to achieve maximum throughput, the design of the catapult is broken into application specific servers. A new layer of API servers is added so that it can allow the entire network to scale in both directions, i.e.,providing high throughputs (queries/s as well as tx/s through the API servers) while it also allows the backend network to scale independently.

The all new catapult network at the backend is where the blockchaining is. The whole idea of this type of configuration is to independently scale the API (the number of clients, and therefore the service level) and the blockchain (data replication / security). This sort of configuration allows for enterprise class deployment. They not only comply with industry practice, they also take NEM’s blockchain technology one notch up by being able to scale the number of transactions to thousands per sec. Initial results have been most promising. But the ninja boys are sharpening their wares to make it transact at even higher throughputs.

World class and bleeding edge in Blockchain technology design. Most promising indeed!


Is it Micro Service Framework?


That looks like an almost 15-second block average with over 1000 tx/s to me. Pretty fast!


over 1000tps , does it say that cultput will release soon


It says that Catapult is well on its way in development.


Looks like you are working on the API Server gateway now.


updated op


as far as I know, I haven’t seen anything like this on any blockchain. this is really forward thinking. not just thinking about how to scale a blockchain tx load. the reason is, if you do manage to get a billion tx a day, now you have another problem which is how to scale all that data to and from the light clients making those txs which would be A LOT. glad you guys are planning ahead.


updated op :slight_smile: