- Angular – Testing
Testing a pipe, a directive, a guard and an HTTP interceptor. When you need `TestBed` and when `new MyPipe()` is the better test, hosting a directive to exercise its selector, `HttpTestingController` and why `verify()` matters, driving a debounced search with fake timers, and where Playwright takes over from unit tests.
- Docker – Multi-Platform Builds and exec format error
You build on an Apple Silicon Mac, you push, the server says `exec format error`. Why that happens, what buildx and QEMU do about it, `--platform` for one target and a manifest list for both, what emulated builds cost in time, and the `--platform=$BUILDPLATFORM` trick that makes a cross build fast again.
- Hasura – Logging, Metrics and Tracing
Knowing what your API is doing once real traffic hits it. The log types Hasura can emit and which ones are worth turning on, reading a query log to find the slow operation rather than guessing, the health and metrics endpoints, and tracing a request across Hasura and the service behind an Action. Plus what changes in v3.
- Python Advanced – functools, operator, and reduce
The functional toolkit that survives the comprehension argument: reduce where it is genuinely the right shape, partial for pre-filling arguments, cache and singledispatch, and the operator module that replaces most small lambdas.
- Python – User Input
`input()` always hands you a string, which is where most beginner bugs start. Validating and converting it, looping until the answer is usable, hidden input for passwords, and `argparse` when the input is command-line arguments instead.