Redis on Luther Monson

A Lock Is Only as Good as Its Release

Tue, 13 Oct 2026 20:40:00 -0700

Every “build a lock on Redis” tutorial spends its time on acquisition: SET key value NX PX 30000, one winner, done. The release gets one line, DEL key. That line is where most of the lock bugs I’ve had in ePHPm lived. Over about three months the same mistake showed up in three places. First the native session handler, then two of the Composer wrapper packages, and finally the cluster. Each time it wore a slightly different costume.

Calling Rust From PHP Without a Socket, Part 2: Making Existing Code Use It

Mon, 21 Sep 2026 19:55:00 -0700

Part 1 covered the plumbing. ePHPm registers ephpm_kv_* and ephpm_db_* functions that call straight into Rust. A cache read through one costs about a tenth of a microsecond instead of a loopback round trip. That’s nice and also useless on its own. Nobody is going to rewrite their WordPress object cache or their Laravel cache store around a function called ephpm_kv_set(). Applications talk to existing APIs instead:

Redis through phpredis or Predis
the cache through PSR-6/16 or wp_cache_*
the database through wpdb, mysqli, Eloquent or DBAL

So there’s a set of Composer packages in the ephpm org whose whole job is to sit under those APIs and route them to the native functions. This post covers what’s in them and the rule that decides when they switch on. It also covers the bugs that only showed up once real applications ran on top.

Calling Rust From PHP Without a Socket, Part 1: The Native Functions

Mon, 14 Sep 2026 20:40:00 -0700

ePHPm is a single Rust binary that embeds PHP. It carries its own KV store and its own SQLite-backed database in the same process. For a long time PHP code could only reach that KV store the same way it reaches Redis. It opened a TCP socket to the RESP listener ePHPm runs on localhost, encoded a command and waited for the reply. That works, and every PHP Redis client in existence already speaks it. But it is a strange thing to do when the hash map you’re talking to lives a few pointers away in the same address space.

Rolling Your Own KV Store Instead of Embedding Redis

Mon, 17 Aug 2026 20:44:00 -0700

Every PHP deployment I’ve run eventually grew a Redis. Sessions, the WordPress object cache, Laravel’s cache and locks, rate limiting. ePHPm is supposed to be one binary that replaces nginx + php-fpm + Redis, so it needed a cache in the box. I didn’t want to write one. This post covers why I did anyway and how it’s built. It also covers the bug that sat in its eviction code from March until last month. Then I compare it against a stock Redis on the same machine with redis-benchmark doing the talking.