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Running a Bash script forever
It is somewhat desirable to have a Bash script run forever; typical use case is for a long-running Docker container that backgrounds the service, and the startup script (e.g., invoked via the ENTRYPOINT command) needs to be kept alive (terminating the script would result in the process known-as “the container” to terminate too). I have…
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Uncompromising Python Formatting
I wanted to give a shout out to Black, “the uncompromising Python code formatter.” It really is liberating not to have to worry about code formatting, not having to have unproductive, sterile discussions over PRs about code minutiae and yet being reassured that all your code is nicely formatted; most importantly, the quality of the…
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HOW-TO Install Minikube on MacOS
Minikube is an extremely useful tool to run a development Kubernetes single-node cluster locally, on a development machine. I use it regularly on my Linux box and, as I want to do development on my MacBook Pro too, I thought I’d use it there to. In order to do so, I have created a simple…
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QNAP NAS Hybrid Backup Sync restart
I have now had a TS-212 QNAP NAS for many years and I am really (really!) happy with it: it works exceedingly well for what I originally bought it for (a networked backup drive, essentially) but it has also so many more facilities that I really have come to depend on it for a number…
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HOW-TO Move your code out of GitHub
As everyone knows by now, Microsoft has bought Github for several $BN’s. Depending on your point of view, this can be either a catastrophe or a disaster: nothing good can possibly come out of it, apart from, possibly, having prevented Github (the corporation) going into a steady, sad decline, as they seemed unable to figure…
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Beware of C++11 `auto`
Here’s a puzzler for you: given the code below, what does the for loop print? using HandlersMap = std::map<std::string, std::function<std::string(const std::string&)>>; using MetaMap = std::map<std::string, HandlersMap>; void insert(MetaMap& meta, const std::string& key, const std::string& sub) { auto handlers = meta[key]; handlers[sub] = [=](const std::string& msg) { return “The response for ” + sub + “…
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Detection of Fast-Moving Objects (FOM) using OpenCV
A “fast-moving object” (FOM) in the world of image detection is defined as one whose motion is faster than can be captured by a single image, and will result in a blurred “streak”. This poses some challenges when trying to detect its speed and trajectory, as well as estimating future trajectory and impact. Typical examples…
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File Encryption Utility now offers file sharing
With the 0.5.0 version just released, crytto now allows file sharing (e.g., via email) by sharing public keys: encrypt_send -o /tmp/my-secret.enc \ -p /home/marco/.ssh/my-key.pub \ ./my-secret.doc This generates an encrypted file (in the location specified with the -o option) and an equally encrypted “passphrase” which can then be sent (ideally via a separate sharing mechanism; although, as…
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Gossip-based Failure Detectors – 0.8.0 released
We have just released version 0.8.0 of our distlib C++ library that implements a number of popular distributed systems algorithms. This concludes a first iteration of the “SWIM Gossip Protocol” for failure detection: the implementation is now fully thread-safe and can scale up to many servers with minimal process overhead. The gossip_example.cpp toy server shows how a client…
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File Encryption (and Decryption) Made Easy
A new release of the Crytto library (0.4.0) has just been published, which greatly simplifies encrypting (and decrypting) files The new release adds the decrypt script which, when combined with the existing automatic retrieval of the encryption key from the keystore, makes it a breeze to decrypt files. For example, if you had encrypted your…
Code Trips & Tips
Adventures in developing distributed systems in Go, Java , Python and C++
Code Trips & Tips 