Convert CEL to Expr

.gitignore

@@ -2,3 +2,5 @@
 bin/
 *.out
 web/main.wasm
+web/assets/main.wasm.gz
+web/assets/data.json

CONTRIBUTING.md

@@ -1,14 +1,19 @@
-# Contributing to CEL Playground
+# Contributing to Expr Playground
 
 :+1::tada: Thanks for taking the time to contribute! :tada::+1:
 
-The following is a set of guidelines for contributing to CEL Playground, 
-which are hosted in the [Undistro Organization](https://github.com/undistro) on GitHub. 
+The following is a set of guidelines for contributing to Expr Playground, 
+which is maintained by [polds](https://github.com/polds) on GitHub.
+
+## CEL Playground
+
+Expr playground is a fork of [CEL Playground](https://github.com/undistro/cel-playground) but swapping CEL support for 
+[Expr](https://expr-lang.org/) support. Please make sure to check out their project and give them a star as well!
 
 ## How Can I Contribute?
 
 - **Giving us a star.** It may not seem like much, but it really makes a
-  difference. This is something that everyone can do to help out CEL Playground.
+  difference. This is something that everyone can do to help out Expr Playground.
   GitHub stars help the project gain visibility and stand out.
 
 - **Reviewing the documentation.** 
@@ -17,9 +22,9 @@ which are hosted in the [Undistro Organization](https://github.com/undistro) on
   feel free to open a Pull Request with your suggestions.
 
 - **Reporting bugs.** We use GitHub issues to track public bugs. 
-  Report a bug by [opening a new issue](https://github.com/undistro/cel-playground/issues/new/choose).
+  Report a bug by [opening a new issue](https://github.com/polds/expr-playground/issues/new/choose).
 
 - **Pull Request.** Unless you are fixing a known bug, we **strongly** 
   recommend discussing it with the core team via a GitHub issue before 
-  getting started to ensure your work is consistent with CEL Playground's roadmap and architecture.
+  getting started to ensure your work is consistent with Expr Playground's roadmap and architecture.
 

Makefile

@@ -1,4 +1,4 @@
-CEL_GO_VERSION=$(shell go list -f "{{.Version}}" -m github.com/google/cel-go)
+EXPR_GO_VERSION=$(shell go list -f "{{.Version}}" -m github.com/expr-lang/expr)
 
 # Setting SHELL to bash allows bash commands to be executed by recipes.
 # Options are set to exit when a recipe line exits non-zero or a piped command fails.
@@ -25,31 +25,29 @@ test: fmt ## Run tests.
 	go test ./... -coverprofile cover.out
 
 .PHONY: serve
-serve: ## Serve static files.
-	python3 -m http.server -d web/ 8080
-	#Uncomment the command below to serve with Go
-	#go run cmd/server/main.go --dir web/
+serve: build ## Serve static files.
+	go run cmd/server/main.go
 
 .PHONY: update-data
 update-data: ## Update the web/assets/data.json file.
 	yq -ojson '.' examples.yaml > web/assets/data.json
-	yq -ojson -i '.versions.cel-go = "$(CEL_GO_VERSION)"' web/assets/data.json
+	yq -ojson -i '.versions.expr = "$(EXPR_GO_VERSION)"' web/assets/data.json
 
 .PHONY: addlicense
 addlicense: ## Add copyright license headers in source code files.
 	@test -s $(LOCALBIN)/addlicense || GOBIN=$(LOCALBIN) go install github.com/google/addlicense@latest
-	$(LOCALBIN)/addlicense -c "Undistro Authors" -l "apache" -ignore ".github/**" -ignore ".idea/**" -ignore "web/dist/**" .
+	$(LOCALBIN)/addlicense -c "Undistro Authors; Fork and conversion to Expr by Peter Olds <me@polds.dev>" -l "apache" -ignore ".github/**" -ignore ".idea/**" -ignore "web/dist/**" .
 
 .PHONY: checklicense
 checklicense: ## Check copyright license headers in source code files.
 	@test -s $(LOCALBIN)/addlicense || GOBIN=$(LOCALBIN) go install github.com/google/addlicense@latest
-	$(LOCALBIN)/addlicense -c "Undistro Authors" -l "apache" -ignore ".github/**" -ignore ".idea/**" -ignore "web/dist/**" -check .
+	$(LOCALBIN)/addlicense -c "Undistro Authors; Fork and conversion to Expr by Peter Olds <me@polds.dev>" -l "apache" -ignore ".github/**" -ignore ".idea/**" -ignore "web/dist/**" -check .
 
 ##@ Build
 
 .PHONY: build
 build: fmt update-data ## Build the wasm binary.
-	GOOS=js GOARCH=wasm go build -ldflags="-s -w" -o web/assets/main.wasm cmd/wasm/main.go
+	GOOS=js GOARCH=wasm go build -trimpath -ldflags="-s -w" -o web/assets/main.wasm cmd/wasm/main.go
 	gzip --best -f web/assets/main.wasm
 
 ## Location to install dependencies to

README.md

@@ -1,20 +1,23 @@
-# CEL Playground
-![GitHub](https://img.shields.io/github/license/undistro/cel-playground)
-[![Go Report Card](https://goreportcard.com/badge/github.com/undistro/cel-playground)](https://goreportcard.com/report/github.com/undistro/cel-playground)
+# Expr Playground
+![GitHub](https://img.shields.io/github/license/polds/expr-playground)
+[![Go Report Card](https://goreportcard.com/badge/github.com/polds/expr-playground)](https://goreportcard.com/report/github.com/polds/expr-playground)
 
-CEL Playground is an interactive WebAssembly (Wasm) powered environment to explore and experiment with the [Common Expression Language (CEL)](https://github.com/google/cel-spec).
-It provides a simple and user-friendly interface to write and quickly evaluate CEL expressions.
+Expr Playground is an interactive WebAssembly (Wasm) powered environment to explore and experiment with 
+[Expr-lang](https://expr-lang.org/). It provides a simple and user-friendly interface to write and quickly evaluate 
+Expr expressions.
 
-## CEL libraries
+## Credits
 
-CEL Playground is built by compiling Go code to WebAssembly and includes the following libraries that are available in the environment:
+This project is forked from [CEL Playground](https://github.com/undistro/cel-playground) and modified to support Expr. 
+Please be sure to check out their project and give them a star as well!
 
-- CEL [extended string function library](https://pkg.go.dev/github.com/google/cel-go/ext#Strings)
-- [Kubernetes list library](https://kubernetes.io/docs/reference/using-api/cel/#kubernetes-list-library)
-- [Kubernetes regex library](https://kubernetes.io/docs/reference/using-api/cel/#kubernetes-regex-library)
-- [Kubernetes URL library](https://kubernetes.io/docs/reference/using-api/cel/#kubernetes-url-library)
+## Expr libraries
 
-Take a look at [all the environment options](eval/eval.go#L26).
+CEL Playground is built by compiling Go code to WebAssembly. At present only the Expr engine is available in this 
+environment. We will look at injecting some other utilities to make this environment more useful, on-par with the the
+CEL standard library and CEL Playground.
+
+Take a look at [all the environment options](eval/eval.go#L31).
 
 ## Development
 
@@ -31,8 +34,8 @@ make serve
 ## Contributing
 
 We appreciate your contribution.
-Please refer to our [contributing guideline](https://github.com/undistro/cel-playground/blob/main/CONTRIBUTING.md) for further information.
-This project adheres to the Contributor Covenant [code of conduct](https://github.com/undistro/cel-playground/blob/main/CODE_OF_CONDUCT.md).
+Please refer to our [contributing guideline](https://github.com/polds/expr-playground/blob/main/CONTRIBUTING.md) for further information.
+This project adheres to the Contributor Covenant [code of conduct](https://github.com/polds/expr-playground/blob/main/CODE_OF_CONDUCT.md).
 
 ## License
 

cmd/server/main.go

@@ -1,4 +1,5 @@
 // Copyright 2023 Undistro Authors
+// Modifications Fork and conversion to Expr Copyright 2024 Peter Olds <me@polds.dev>
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -18,16 +19,17 @@ import (
 	"flag"
 	"log"
 	"net/http"
+
+	"github.com/polds/expr-playground/web"
 )
 
 var (
 	listen = flag.String("listen", ":8080", "listen address")
-	dir    = flag.String("dir", ".", "directory to serve")
 )
 
 func main() {
 	flag.Parse()
 	log.Printf("listening on %s...", *listen)
-	err := http.ListenAndServe(*listen, http.FileServer(http.Dir(*dir)))
+	err := http.ListenAndServe(*listen, http.FileServer(http.FS(web.Assets)))
 	log.Fatalln(err)
 }

cmd/wasm/main.go

@@ -1,4 +1,5 @@
 // Copyright 2023 Undistro Authors
+// Modifications Fork and conversion to Expr Copyright 2024 Peter Olds <me@polds.dev>
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -23,7 +24,7 @@ import (
 
 	"gopkg.in/yaml.v3"
 
-	"github.com/undistro/cel-playground/eval"
+	"github.com/polds/expr-playground/eval"
 )
 
 func main() {

eval/eval.go

@@ -1,4 +1,5 @@
 // Copyright 2023 Undistro Authors
+// Modifications Fork and conversion to Expr Copyright 2024 Peter Olds <me@polds.dev>
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -17,116 +18,39 @@ package eval
 import (
 	"encoding/json"
 	"fmt"
-	"reflect"
 
-	"github.com/google/cel-go/cel"
-	"github.com/google/cel-go/checker"
-	"github.com/google/cel-go/common/types/ref"
-	"github.com/google/cel-go/ext"
-	"github.com/google/cel-go/interpreter"
-	"google.golang.org/protobuf/types/known/structpb"
-	k8s "k8s.io/apiserver/pkg/cel/library"
+	"github.com/expr-lang/expr"
+	"github.com/expr-lang/expr/vm"
 )
 
-type EvalResponse struct {
-	Result any     `json:"result"`
-	Cost   *uint64 `json:"cost, omitempty"`
+type RunResponse struct {
+	Result   any         `json:"result"`
+	Bytecode []vm.Opcode `json:"bytecode"`
 }
 
-var celEnvOptions = []cel.EnvOption{
-	// 1.0 (1.23)
-	cel.HomogeneousAggregateLiterals(),
-	cel.EagerlyValidateDeclarations(true),
-	cel.DefaultUTCTimeZone(true),
-	k8s.URLs(),
-	k8s.Regex(),
-	k8s.Lists(),
-
-	// 1.27
-	// k8s.Authz(),
-
-	// 1.28
-	cel.CrossTypeNumericComparisons(true),
-	cel.OptionalTypes(),
-	k8s.Quantity(),
-
-	// 1.29 (see also validator.ExtendedValidations())
-	cel.ASTValidators(
-		cel.ValidateDurationLiterals(),
-		cel.ValidateTimestampLiterals(),
-		cel.ValidateRegexLiterals(),
-		cel.ValidateHomogeneousAggregateLiterals(),
-	),
-
-	// Strings (from 1.29 onwards)
-	ext.Strings(ext.StringsVersion(2)),
-	// Set library (1.29 onwards)
-	ext.Sets(),
-
-	// cel-go v0.17.7 introduced CostEstimatorOptions.
-	// Previous the presence has a cost of 0 but cel fixed it to 1. We still set to 0 here to avoid breaking changes.
-	cel.CostEstimatorOptions(checker.PresenceTestHasCost(false)),
+var exprEnvOptions = []expr.Option{
+	expr.AsAny(),
 }
 
-var celProgramOptions = []cel.ProgramOption{
-	cel.EvalOptions(cel.OptOptimize, cel.OptTrackCost),
-
-	// cel-go v0.17.7 introduced CostTrackerOptions.
-	// Previous the presence has a cost of 0 but cel fixed it to 1. We still set to 0 here to avoid breaking changes.
-	cel.CostTrackerOptions(interpreter.PresenceTestHasCost(false)),
-}
-
-// Eval evaluates the cel expression against the given input
+// Eval evaluates the expr expression against the given input.
 func Eval(exp string, input map[string]any) (string, error) {
-	inputVars := make([]cel.EnvOption, 0, len(input))
-	for k := range input {
-		inputVars = append(inputVars, cel.Variable(k, cel.DynType))
-	}
-	env, err := cel.NewEnv(append(celEnvOptions, inputVars...)...)
-	if err != nil {
-		return "", fmt.Errorf("failed to create CEL env: %w", err)
-	}
-	ast, issues := env.Compile(exp)
-	if issues != nil {
-		return "", fmt.Errorf("failed to compile the CEL expression: %s", issues.String())
-	}
-	prog, err := env.Program(ast, celProgramOptions...)
+	exprEnvOptions = append(exprEnvOptions, expr.Env(input))
+	program, err := expr.Compile(exp, exprEnvOptions...)
 	if err != nil {
-		return "", fmt.Errorf("failed to instantiate CEL program: %w", err)
+		return "", fmt.Errorf("failed to compile the Expr expression: %w", err)
 	}
-	val, costTracker, err := prog.Eval(input)
+	output, err := expr.Run(program, input)
 	if err != nil {
 		return "", fmt.Errorf("failed to evaluate: %w", err)
 	}
 
-	response, err := generateResponse(val, costTracker)
-	if err != nil {
-		return "", fmt.Errorf("failed to generate the response: %w", err)
+	res := &RunResponse{
+		Result:   output,
+		Bytecode: program.Bytecode,
 	}
-
-	out, err := json.Marshal(response)
+	out, err := json.MarshalIndent(res, "", "  ")
 	if err != nil {
 		return "", fmt.Errorf("failed to marshal the output: %w", err)
 	}
 	return string(out), nil
 }
-
-func getResults(val *ref.Val) (any, error) {
-	if value, err := (*val).ConvertToNative(reflect.TypeOf(&structpb.Value{})); err != nil {
-		return nil, err
-	} else {
-		return value, nil
-	}
-}
-
-func generateResponse(val ref.Val, costTracker *cel.EvalDetails) (*EvalResponse, error) {
-	result, evalError := getResults(&val)
-	if evalError != nil {
-		return nil, evalError
-	}
-	cost := costTracker.ActualCost()
-	return &EvalResponse{
-		Result: result,
-		Cost:   cost,
-	}, nil
-}