Sometimes it's helpful to be able to list which SSL/TLS ciphers a remote server supports.
This snippet allows you to connect with OpenSSL in order to generate a list (but can only check those supported by the system you're running it on)
When trying to work out where all your RAM went, it's sometimes useful to be able to take a look at what currently has pages in swap.
It's worth bearing in mind, though, that processes listed aren't necessarily the root cause - they may well have been paged out to free up RAM for some other process
When ordering new RAM, you tend to want to know if there are any free slots, as well as what you've already got installed
Having to remove the cover to check isn't particularly convenient though. This snippet details how to check from Linux
Initially roughly patched together in Musings on Home Automation this script is intended to work around the fact that Google's NEST Thermostat doesn't have a "boost" function - making it a bit tricky if you want a part of the house not containing the NEST thermostat to be able to call for heat.
The basic idea is that it will increase the NEST target temperature by a configurable amount for 30 minutes, causing the boiler to come on if it was off.
So that the script can track state, you need to create a number input with ID current_heating_target and another with ID heating_boost_degrees (set it to 5)
We've a wall light in our hall whose main lightswitch is poorly placed. So, I put a smart bulb in and put a Zigbee button in a more convenient place.
However, the light is brighter than a thousand suns, so I wanted a it to come on at just under half brightness by default, with an option to turn it up to full (in case someone loses a contact, or is bored of having retinas)
The following script in HomeAssistant/Hass.io achieves that.
One of the things that an trip you up, is checking the current brightness state - it's not reported as a percentage, but as a (I assume) byte value.
Just occasionally, you'll be looking into performance issues and find that, for some reason, someone has disabled read-ahead when creating virtual disks in the raid controller.
Dell's documentation tells you how to modify this in such an obscure and obfuscated way that it's almost a match for HP's server documentation.
This snippet details how to change read-ahead for disks on a Dell RAID controller using racadm
It's sometimes desirable to limit the rate at which connections can be established with a server - whether to act as a defense against simpler DDoS's or simply to enforce usage limits
This snippet details how to use the hashlimit module to limit connection rates
The lua-resty-http is incredbily useful when you need some LUA in OpenResty to place external HTTP requests.
However, when you need it to do HTTPS things are just a little more complex - it's not a simple as passing it https as a scheme, instead you need to make a specific call to trigger the SSL handshake
This snippet shows how to do that (using a keepalive pool to reduce connection overhead between requests)
Python's urllib module is pretty flexible, and contains a bunch of useful tools - including the ability to urlencode strings via urllib.parse.quote()
Unfortunately, it doesn't allow you to specify what case should be used in URL encoding, and defaults to upper-case. Many other libraries/languages use lower case.
This becomes problematic where you're url encoding an authentication token (or similar) - when the other side mints a token for comparison, the two will not match in a like for like comparison (and if the other end urldecodes your input, they're doing more processing on untrusted input that should be necessary - similarly passing through lower will affect the entire token and massively increase the chance of collisions).
This little wrapper function allows you to do a lowercase url-encode
We've all seen too many open files when we hit FD limits from time to time, but how do you check what the limits for a given process actually are?
The information is exposed within the /proc filesystem