Custom Storage

ACOR does not support custom storage backends. Redis is the only one, and Create() always builds it. This page explains why the interface you may have seen in older releases is gone, and what to do instead for the case it was usually reached for: testing.

What changed in v1.5.0

Through v1.4.0 the package exported KVStorage along with Pipeliner, Subscription, StringMapResult, PubSubMessage, and Z, in anticipation of pluggable backends. They are unexported as of v1.5.0, for two reasons:

• Nothing could be plugged in. No public constructor accepted a KVStorage and no public function returned one, so the capability the interface implied never existed.
• Freezing it would have blocked the feature it was for. The compatibility policy forbids adding a method to an exported interface inside v1. KVStorage has 23 methods; freezing it would have left a future backend needing one more operation nowhere to put it for the rest of v1.

Publishing an interface later is an addition, which v1 allows; growing a frozen one is not.

Testing without Redis

This is what the interface was most often reached for, and miniredis answers it today — an in-process Redis-compatible server. ACOR’s own test suite uses it, so the behavior you test against is the behavior ACOR is tested against.

package example

import (
    "testing"

    "github.com/alicebob/miniredis/v2"
    "github.com/skyoo2003/acor/pkg/acor"
)

func TestWithMiniredis(t *testing.T) {
    mr := miniredis.RunT(t)

    ac, err := acor.Create(&acor.AhoCorasickArgs{
        Addr: mr.Addr(),
        Name: "test-collection",
    })
    if err != nil {
        t.Fatal(err)
    }
    defer func() { _ = ac.Close() }()

    if _, err := ac.Add("hello"); err != nil {
        t.Fatal(err)
    }

    matches, err := ac.Find("hello world")
    if err != nil {
        t.Fatal(err)
    }
    if len(matches) != 1 || matches[0] != "hello" {
        t.Fatalf("Find() = %v, want [hello]", matches)
    }
}

miniredis covers the commands ACOR issues, including the Lua scripts V2 uses for atomic writes. To exercise Pub/Sub-driven invalidation across instances, point two instances at the same miniredis address.

Reducing Redis traffic

If the reason for a custom backend was avoiding round trips on reads rather than replacing Redis, that is already available:

• Preset serves reads from a local automaton and touches Redis only on writes and invalidations — see Preset-Optimized Engine.
• EnableCache caches trie data locally and invalidates over Pub/Sub.

CacheStats() reports whether either is working — hit rate, rebuild cost, invalidation lag — with no Redis I/O of its own.