Add ccache

One day we'll look at modern LRU algorithms, such as S3LRU or Sieve.

caching_parser.go

@@ -1,30 +1,35 @@
 package expr
 
 import (
-	"sync"
 	"sync/atomic"
+	"time"
 
 	"github.com/google/cel-go/cel"
-	// "github.com/karlseguin/ccache/v2"
+	"github.com/karlseguin/ccache/v2"
 )
 
 var (
+	CacheTime = time.Hour
+
 	replace = []string{"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t"}
 )
 
 // NewCachingParser returns a CELParser which lifts quoted literals out of the expression
 // as variables and uses caching to cache expression parsing, resulting in improved
 // performance when parsing expressions.
-func NewCachingParser(env *cel.Env) CELParser {
+func NewCachingParser(env *cel.Env, cache *ccache.Cache) CELParser {
+	if cache == nil {
+		cache = ccache.New(ccache.Configure())
+	}
 	return &cachingParser{
-		env: env,
+		cache: cache,
+		env:   env,
 	}
 }
 
 type cachingParser struct {
 	// cache is a global cache of precompiled expressions.
-	// cache *ccache.Cache
-	stupidNoInternetCache sync.Map
+	cache *ccache.Cache
 
 	env *cel.Env
 
@@ -35,20 +40,20 @@ type cachingParser struct {
 func (c *cachingParser) Parse(expr string) (*cel.Ast, *cel.Issues, LiftedArgs) {
 	expr, vars := liftLiterals(expr)
 
-	// TODO: ccache, when I have internet.
-	if cached, ok := c.stupidNoInternetCache.Load(expr); ok {
-		p := cached.(ParsedCelExpr)
+	if cached := c.cache.Get(expr); cached != nil {
+		cached.Extend(CacheTime)
+		p := cached.Value().(ParsedCelExpr)
 		atomic.AddInt64(&c.hits, 1)
 		return p.AST, p.Issues, vars
 	}
 
 	ast, issues := c.env.Parse(expr)
 
-	c.stupidNoInternetCache.Store(expr, ParsedCelExpr{
+	c.cache.Set(expr, ParsedCelExpr{
 		Expr:   expr,
 		AST:    ast,
 		Issues: issues,
-	})
+	}, CacheTime)
 
 	atomic.AddInt64(&c.misses, 1)
 	return ast, issues, vars

expr_test.go

@@ -14,7 +14,9 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func BenchmarkCachingEvaluate1_000(b *testing.B) { benchEval(1_000, NewCachingParser(newEnv()), b) }
+func BenchmarkCachingEvaluate1_000(b *testing.B) {
+	benchEval(1_000, NewCachingParser(newEnv(), nil), b)
+}
 
 // func BenchmarkNonCachingEvaluate1_000(b *testing.B) { benchEval(1_000, EnvParser(newEnv()), b) }
 
@@ -71,7 +73,7 @@ func evaluate(b *testing.B, i int, parser TreeParser) error {
 
 func TestEvaluate(t *testing.T) {
 	ctx := context.Background()
-	parser, err := NewTreeParser(NewCachingParser(newEnv()))
+	parser, err := NewTreeParser(NewCachingParser(newEnv(), nil))
 	require.NoError(t, err)
 	e := NewAggregateEvaluator(parser, testBoolEvaluator)
 
@@ -159,7 +161,7 @@ func TestEvaluate(t *testing.T) {
 
 func TestEvaluate_ArrayIndexes(t *testing.T) {
 	ctx := context.Background()
-	parser, err := NewTreeParser(NewCachingParser(newEnv()))
+	parser, err := NewTreeParser(NewCachingParser(newEnv(), nil))
 	require.NoError(t, err)
 	e := NewAggregateEvaluator(parser, testBoolEvaluator)
 

go.mod

@@ -4,6 +4,7 @@ go 1.21.0
 
 require (
 	github.com/google/cel-go v0.18.2
+	github.com/karlseguin/ccache/v2 v2.0.8
 	github.com/ohler55/ojg v1.21.0
 	github.com/plar/go-adaptive-radix-tree v1.0.5
 	github.com/stretchr/testify v1.8.4

go.sum

@@ -9,6 +9,10 @@ github.com/google/cel-go v0.18.2/go.mod h1:kWcIzTsPX0zmQ+H3TirHstLLf9ep5QTsZBN9u
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
 github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/karlseguin/ccache/v2 v2.0.8 h1:lT38cE//uyf6KcFok0rlgXtGFBWxkI6h/qg4tbFyDnA=
+github.com/karlseguin/ccache/v2 v2.0.8/go.mod h1:2BDThcfQMf/c0jnZowt16eW405XIqZPavt+HoYEtcxQ=
+github.com/karlseguin/expect v1.0.2-0.20190806010014-778a5f0c6003 h1:vJ0Snvo+SLMY72r5J4sEfkuE7AFbixEP2qRbEcum/wA=
+github.com/karlseguin/expect v1.0.2-0.20190806010014-778a5f0c6003/go.mod h1:zNBxMY8P21owkeogJELCLeHIt+voOSduHYTFUbwRAV8=
 github.com/ohler55/ojg v1.21.0 h1:niqSS6yl3PQZJrqh7pKs/zinl4HebGe8urXEfpvlpYY=
 github.com/ohler55/ojg v1.21.0/go.mod h1:gQhDVpQLqrmnd2eqGAvJtn+NfKoYJbe/A4Sj3/Vro4o=
 github.com/plar/go-adaptive-radix-tree v1.0.5 h1:rHR89qy/6c24TBAHullFMrJsU9hGlKmPibdBGU6/gbM=
@@ -26,6 +30,8 @@ github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO
 github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+github.com/wsxiaoys/terminal v0.0.0-20160513160801-0940f3fc43a0 h1:3UeQBvD0TFrlVjOeLOBz+CPAI8dnbqNSVwUwRrkp7vQ=
+github.com/wsxiaoys/terminal v0.0.0-20160513160801-0940f3fc43a0/go.mod h1:IXCdmsXIht47RaVFLEdVnh1t+pgYtTAhQGj73kz+2DM=
 golang.org/x/exp v0.0.0-20230515195305-f3d0a9c9a5cc h1:mCRnTeVUjcrhlRmO0VK8a6k6Rrf6TF9htwo2pJVSjIU=
 golang.org/x/exp v0.0.0-20230515195305-f3d0a9c9a5cc/go.mod h1:V1LtkGg67GoY2N1AnLN78QLrzxkLyJw7RJb1gzOOz9w=
 golang.org/x/text v0.9.0 h1:2sjJmO8cDvYveuX97RDLsxlyUxLl+GHoLxBiRdHllBE=

parser_test.go

@@ -979,7 +979,7 @@ func TestParse(t *testing.T) {
 func TestParse_LiftedVars(t *testing.T) {
 	ctx := context.Background()
 
-	cachingCelParser := NewCachingParser(newEnv())
+	cachingCelParser := NewCachingParser(newEnv(), nil)
 
 	assert := func(t *testing.T, tests []parseTestInput) {
 		t.Helper()