feat: add cache to cel expressions

go.mod

@@ -14,6 +14,7 @@ require (
 	github.com/itchyny/gojq v0.12.14
 	github.com/mitchellh/reflectwalk v1.0.2
 	github.com/ohler55/ojg v1.20.2
+	github.com/patrickmn/go-cache v2.1.0+incompatible
 	github.com/pkg/errors v0.9.1
 	github.com/robertkrimen/otto v0.2.1
 	github.com/stretchr/testify v1.8.4
@@ -22,6 +23,7 @@ require (
 	golang.org/x/tools v0.16.1
 	google.golang.org/protobuf v1.32.0
 	gotest.tools/v3 v3.5.1
+	k8s.io/api v0.28.2
 	k8s.io/apimachinery v0.28.2
 	sigs.k8s.io/yaml v1.3.0
 )
@@ -54,7 +56,6 @@ require (
 	gopkg.in/sourcemap.v1 v1.0.5 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
-	k8s.io/api v0.28.2 // indirect
 	k8s.io/klog/v2 v2.100.1 // indirect
 	k8s.io/utils v0.0.0-20230726121419-3b25d923346b // indirect
 	layeh.com/gopher-json v0.0.0-20201124131017-552bb3c4c3bf // indirect

go.sum

@@ -53,6 +53,8 @@ github.com/modern-go/reflect2 v1.0.2 h1:xBagoLtFs94CBntxluKeaWgTMpvLxC4ur3nMaC9G
 github.com/modern-go/reflect2 v1.0.2/go.mod h1:yWuevngMOJpCy52FWWMvUC8ws7m/LJsjYzDa0/r8luk=
 github.com/ohler55/ojg v1.20.2 h1:ragZXnawcsq/knqIHaflvIX/8RzzAKMZSluAZAz+RFs=
 github.com/ohler55/ojg v1.20.2/go.mod h1:uHcD1ErbErC27Zhb5Df2jUjbseLLcmOCo6oxSr3jZxo=
+github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaRUnok+kx1WdO15EQc=
+github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=

template.go

@@ -5,13 +5,16 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"slices"
 	"strings"
 	gotemplate "text/template"
+	"time"
 
 	_ "github.com/flanksource/gomplate/v3/js"
 	"github.com/google/cel-go/cel"
 	"github.com/google/cel-go/common/types"
 	"github.com/google/cel-go/common/types/ref"
+	"github.com/patrickmn/go-cache"
 	"github.com/pkg/errors"
 	"github.com/robertkrimen/otto"
 	"github.com/robertkrimen/otto/registry"
@@ -20,6 +23,11 @@ import (
 
 var funcMap gotemplate.FuncMap
 
+var (
+	goTemplateCache    = cache.New(24*time.Hour, 24*time.Hour)
+	celExpressionCache = cache.New(24*time.Hour, 24*time.Hour)
+)
+
 func init() {
 	funcMap = CreateFuncs(context.Background())
 }
@@ -39,17 +47,16 @@ func (t Template) IsEmpty() bool {
 }
 
 func RunExpression(_environment map[string]any, template Template) (any, error) {
-
 	data, err := Serialize(_environment)
 	if err != nil {
 		return "", err
 	}
 
-	funcs := GetCelEnv(data)
+	envOptions := GetCelEnv(data)
 	for name, fn := range template.Functions {
 		_name := name
 		_fn := fn
-		funcs = append(funcs, cel.Function(_name, cel.Overload(
+		envOptions = append(envOptions, cel.Function(_name, cel.Overload(
 			_name,
 			nil,
 			cel.AnyType,
@@ -60,18 +67,34 @@ func RunExpression(_environment map[string]any, template Template) (any, error)
 		)))
 	}
 
-	env, err := cel.NewEnv(funcs...)
-	if err != nil {
-		return "", err
-	}
-	ast, issues := env.Compile(strings.ReplaceAll(template.Expression, "\n", " "))
-	if issues != nil && issues.Err() != nil {
-		return "", issues.Err()
+	var prg cel.Program
+	if len(template.Functions) == 0 {
+		// only use cache if there's no custom template functions because we can't hash those functions to use them as a cache key
+		cached, ok := celExpressionCache.Get(cacheKey(_environment, template.Expression))
+		if ok {
+			if cachedPrg, ok := cached.(*cel.Program); ok {
+				prg = *cachedPrg
+			}
+		}
 	}
 
-	prg, err := env.Program(ast, cel.Globals(data))
-	if err != nil {
-		return "", err
+	if prg == nil {
+		env, err := cel.NewEnv(envOptions...)
+		if err != nil {
+			return "", err
+		}
+
+		ast, issues := env.Compile(strings.ReplaceAll(template.Expression, "\n", " "))
+		if issues != nil && issues.Err() != nil {
+			return "", issues.Err()
+		}
+
+		prg, err = env.Program(ast, cel.Globals(data))
+		if err != nil {
+			return "", err
+		}
+
+		celExpressionCache.SetDefault(cacheKey(_environment, template.Expression), &prg)
 	}
 
 	out, _, err := prg.Eval(data)
@@ -170,3 +193,14 @@ func LoadSharedLibrary(source string) error {
 	registry.Register(func() string { return string(data) })
 	return nil
 }
+
+// cacheKey for cel expressions
+func cacheKey(env map[string]any, expr string) string {
+	var cacheKey []string
+	for k := range env {
+		cacheKey = append(cacheKey, k)
+	}
+	slices.Sort(cacheKey)
+
+	return strings.Join(cacheKey, "-") + "--" + expr
+}

template_test.go

@@ -0,0 +1,37 @@
+package gomplate
+
+import (
+	"testing"
+
+	_ "github.com/flanksource/gomplate/v3/js"
+	_ "github.com/robertkrimen/otto/underscore"
+)
+
+func Test_hashFunction(t *testing.T) {
+	type args struct {
+		env  map[string]any
+		expr string
+	}
+
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{
+			name: "simple",
+			args: args{
+				expr: "{{.name}}{{.age}}",
+				env:  map[string]any{"age": 19, "name": "james"},
+			},
+			want: "age-name--{{.name}}{{.age}}",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := cacheKey(tt.args.env, tt.args.expr); got != tt.want {
+				t.Errorf("hashFunction() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}