by Bozho | Sep 15, 2017 | Aggregated, Opinions
Self-driving cars are (will be) the pinnacle of consumer products automation – robot vacuum cleaners, smart fridges and TVs are just toys compared to self-driving cars. Both in terms of technology and in terms of impact. We aren’t yet on level 5 self driving cars , but they are behind the corner. But as software engineers we know how fragile software is. And self-driving cars are basically software, so we can see all the risks involved with putting our lives in the hands anonymous (from our point of view) developers and unknown (to us) processes and quality standards. One may argue that this has been the case for every consumer product ever, but with software is different – software is way more complex than anything else. So I have an outrageous proposal – self-driving cars should be open source. We have to be able to verify and trust the code that’s navigating our helpless bodies around the highways. Not only that, but we have to be able to verify if it is indeed that code that is currently running in our car, and not something else. In fact, let me extend that – all cars should be open source. Before you say “but that will ruin the competitive advantage of manufacturers and will be deadly for business”, I don’t actually care how they trained their neural networks, or what their datasets are. That’s actually the secret sauce of the self-driving car and in my view it can remain proprietary and closed. What I’d like to see open-sourced is everything else. (Under what license – I’d be fine to even...
by Bozho | Sep 6, 2017 | Aggregated, Developer tips, Opinions
We’ve all watched dozens of talks online. And we probably don’t remember many of them. But some do stick in our heads and we eventually watch them again (and again) because we know they are good and we want to remember the things that were said there. So I decided to compile a small list of talks that I find very insightful, useful and that have, in a way, shaped my software engineering practice or expanded my understanding of the software world. 1. How To Design A Good API and Why it Matters by Joshua Bloch – this is a must-watch (well, obviously all are). And don’t skip it because “you are not writing APIs” – everyone is writing APIs. Maybe not used by hundreds of other developers, but used by at least several, and that’s a good enough reason. Having watched this talk I ended up buying and reading one of the few software books that I have actually read end-to-end – “Effective Java” (the talk uses Java as an example, but the principles aren’t limited to Java) 2. How to write clean, testable code by Miško Hevery. Maybe there are tons of talks about testing code, maybe Uncle Bob has a more popular one, but I found this one particularly practical and the the point – that writing testable code is a skill, and that testable code is good code. (By the way, the speaker then wrote AngularJS) 3. Back to basics: the mess we’ve made of our fundamental data types by Jon Skeet. The title says it all, and it’s nice to be reminded of how...
by Bozho | Aug 21, 2017 | Aggregated, Developer tips
Every project that has a database has dilemma: how to test database-dependent code. There are several options (not mutually exclusive): Use mocks – use only unit tests and mock the data-access layer, assuming the DAO-to-database communication works Use an embedded database that each test starts and shuts down. This can also be viewed as unit-testing Use a real database deployed somewhere (either locally or on a test environment). The hard part is making sure it’s always in a clean state. Use end-to-end/functional tests/bdd/UI tests after deploying the application on a test server (which has a proper database). None of the above is without problems. Unit tests with mocked DAOs can’t really test more complex interactions that rely on a database state. Embedded databases are not always available (e.g. if you are using a non-relational database, or if you rely on RDBMS-specific functionality, HSQLDB won’t do), or they can be slow to start and this your tests may take too long supporting. A real database installation complicates setup and keeping it clean is not always easy. The coverage of end-to-end tests can’t be easily measured and they don’t necessarily cover all the edge cases, as they are harder to maintain than unit and integration tests. I’ve recently tried a strange approach that is working pretty well so far – stubbing the database. It is applicable more to key-value stores and less to relational databases. In my case, even though there is embedded cassandra, it was slow to start, wasn’t easy to setup and had subtle issues. That’s why I replaced the whole thing with an in-memory ConcurrentHashMap. Since I’m using...
by Bozho | Aug 12, 2017 | Aggregated, Opinions
Yes, it’s about the “anti-diversity memo”. But I won’t go into particular details of the memo, the firing, who’s right and wrong, who’s liberal and who’s conservative. Actually, I don’t need to repeat this post, which states almost exactly what I think about the particular issue. Just in case, and before someone decided to label me as “sexist white male” that knows nothing, I guess should clearly state that I acknowledge that biases against women are real and that I strongly support equal opportunity, and I think there must be more women in technology. I also have to state that I think the author of “the memo” was well-meaning, had some well argued, research-backed points and should not be ostracized. But I want to “rant” about the quality of the debate. On one side we have conservatives who are throwing themselves in defense of the fired googler, insisting that liberals are banning conservative points of view, that it is normal to have so few woman in tech and that everything is actually okay, or even that women are inferior. On the other side we have triggered liberals that are ready to shout “discrimination” and “harassment” at anything that resembles an attempt to claim anything different than total and absolute equality, in many cases using a classical “strawman” argument (e.g. “he’s saying women should not work in tech, he’s obviously wrong”). Everyone seems to be too eager to take side and issue a verdict on who’s right and who’s wrong, to blame the other side for all related and unrelated woes and while doing that, exhibit a huge amount of...
by Bozho | Aug 9, 2017 | Aggregated, Developer tips
After I’ve expressed my concerns about the blockchain technology, let’s get a bit more practical with the blockchain. In particular, with Ethereum. I needed to send a transaction with Java, so I looked at EthereumJ. You have three options: Full node – you enable syncing, which means the whole blockchain gets downloaded. It takes a lot of time, so I abandoned that approach “Light” node – you disable syncing, so you just become part of the network, but don’t fetch any parts of the chain. Not entirely sure, but I think this corresponds to the “light” mode of geth (the ethereum CLI). You are able to send messages (e.g. transaction messages) to other peers to process and store on the blockchain, but you yourself do not have the blockchain. Offline (no node) – just create and sign the transaction, compute its raw representation (in the ethereum RLP format) and push it to the blockchain via a centralized API, e.g. the etherscan.io API. Etherscan is itself a node on the network and it can perform all of the operations (so it serves as a proxy) Before going further, maybe it’s worth pointing out a few general properties of the blockchain (the ethereum one and popular cryptocurrencies at least) – it is a distributed database, relying on a peer-to-peer (overlay) network, formed by whoever has a client software running (wallet or otherwise). Transactions are in the form of “I (private key owner) want to send this amount to that address”. Transactions can have additional data stored inside them, e.g. representing what they are about. Transactions then get verified by peers (currently...
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