systemd Network Readiness - What network-online.target Actually Promises
A service starts during boot, tries to contact a remote endpoint, and fails because the machine has not finished acquiring an address. Addi…
Safe Nginx Configuration Reloads - Validate, Observe, and Keep a Way Back
An Nginx configuration can be valid and still be wrong. A proxy rule may point to the wrong upstream, a hostname may fall into the default …
Prompt Injection for AI Applications — An Instruction Is Not a Security Boundary
A small application reads an incoming email, asks a language model to summarize it, and then, if the summary mentions a task, lets the mode…
Overlapping Scheduled Jobs - Choose a Lock That Matches the Work
A job is scheduled every five minutes, but one run occasionally needs six. When the next trigger arrives, should it start a second copy, wa…
PHP-FPM Unix Socket Permissions - Let Nginx Reach PHP Without Opening the Door to Everyone
Nginx returns a 502 response, and the error log mentions a Unix socket used by PHP-FPM. It is tempting to make that socket writable by ever…
Request IDs for Nginx and PHP - Follow One Request Through the Logs
A PHP request fails, but the visible clues are scattered. Nginx records a status and duration in one file. PHP records an exception somewhe…
etckeeper on a Debian Home Server - Give /etc a Readable History
A Debian server can keep running after a configuration change and still leave an awkward question for later: what exactly changed? Perhaps …
Atomic File Replacement in PHP - Let Readers See the Old File or the New One
A small PHP application may keep a generated manifest, a JSON settings file, or a tiny cache on disk. Writing one is easy. The harder quest…
Composer Lock Files for Small PHP Applications - Deploy the Reviewed Dependencies
A PHP application may deploy successfully on Monday and fail on Friday even when its own source code has not changed. One possible cause is…
Outbound HTTP Requests in PHP - Set Time Limits Before Adding Retries
A small PHP application can call a remote API in only a few lines. The harder question begins when the other system is slow, unreachable, o…