Add Go example for TinyTodo based on cedar-go

.github/workflows/build_tiny_todo_go_reusable.yml

@@ -0,0 +1,39 @@
+name: Build and test TinyTodo-Go
+on:
+    workflow_call:
+      inputs:
+        cedar_policy_ref:
+          required: true
+          type: string
+        cedar_examples_ref:
+          required: true
+          type: string
+
+jobs:
+  build_and_test_tiny_todo_go:
+    name: Build and test TinyTodo-Go
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        go-version: [ '1.22' ]
+    steps:
+      - name: Checkout cedar-examples
+        uses: actions/checkout@v4
+        with:
+          repository: cedar-policy/cedar-examples
+          ref: ${{ inputs.cedar_examples_ref }}
+      - name: Setup Go ${{ matrix.go-version }}
+        uses: actions/setup-go@v5
+        with:
+          go-version: ${{ matrix.go-version }}
+      - name: go vet
+        working-directory: ./tinytodo-go
+        run: go vet ./...
+      - name: go test
+        working-directory: ./tinytodo-go
+        run: go test ./...
+      - name: python test
+        working-directory: ./tinytodo-go
+        run: |
+          go build ./cmd/server
+          python3 -m unittest

.github/workflows/build_tiny_todo_reusable_go.yml

@@ -0,0 +1,52 @@
+name: Build and test TinyTodo
+on:
+    workflow_call:
+      inputs:
+        cedar_policy_ref:
+          required: true
+          type: string
+        cedar_examples_ref:
+          required: true
+          type: string
+
+jobs:
+  build_and_test_tiny_todo:
+    name: Build and test TinyTodo
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        toolchain:
+          - stable
+    steps:
+      - name: Checkout cedar-examples
+        uses: actions/checkout@v4
+        with:
+          repository: cedar-policy/cedar-examples
+          ref: ${{ inputs.cedar_examples_ref }}
+      - name: Use the specified branch
+        run: cd tinytodo && head -n -2 Cargo.toml > Temp.toml && mv Temp.toml Cargo.toml && printf 'rev = "${{ inputs.cedar_policy_ref }}"' >> Cargo.toml
+      - name: rustup
+        run: rustup update ${{ matrix.toolchain }} && rustup default ${{ matrix.toolchain }}
+      - name: cargo fmt
+        working-directory: ./tinytodo
+        run: cargo fmt --all --check
+      - name: cargo rustc
+        working-directory: ./tinytodo
+        run: |
+             RUSTFLAGS="-D warnings -F unsafe-code" cargo build --verbose
+      - name: cargo test
+        working-directory: ./tinytodo
+        run: cargo test --verbose
+      - name: cargo test templates
+        working-directory: ./tinytodo
+        run: cargo test --verbose --features=use-templates
+      - name: python test
+        working-directory: ./tinytodo
+        run: |
+          cargo build --release
+          python3 -m unittest
+      - name: python test templates
+        working-directory: ./tinytodo
+        run: |
+          cargo build --release --features=use-templates
+          python3 -m unittest

README.md

@@ -2,15 +2,16 @@
 
 This repository contains examples demonstrating the use of [Cedar](https://github.com/cedar-policy/cedar), a policy language for writing and enforcing authorization policies in your applications.  The following table summarizes relevant information about the applications. Please refer to the `README.md` files in the subfolders for details about how to build and run them.
 
-| Example      | Languages | Description |
-| ----------- | ----------- | ---------- |
-| [`tinytodo`][] | Rust, Python | A simple application for managing task lists that uses Cedar for authorization |
-| [`cedar-java-hello-world`][] | Java | A simple application demonstrating the usage of the [Cedar Java APIs][] |
-| [`cedar-rust-hello-world`][] | Rust | A simple application demonstrating the usage of the [Cedar Rust APIs][] |
-| [`cedar-wasm-example`][] | TypeScript | A simple application demonstrating the usage of the [Cedar Wasm APIs][] |
-| [`cedar-policy-language-in-action`][] | Cedar | Cedar policies and schemas for the [Cedar policy language in action](https://catalog.workshops.aws/cedar-policy-language-in-action) workshop |
-| [`cedar-example-use-cases`][] |  Cedar  | Cedar policies and schemas for two example applications |
-| [`oopsla2024-benchmarks`][] | Various | Cedar policies and schemas, along with benchmarking code and scripts, used for the performance evaluation of the [OOPSLA2024 paper on Cedar](https://dl.acm.org/doi/10.1145/3649835) |
+| Example                               | Languages    | Description                                                                                                                                                                          |
+|---------------------------------------|--------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| [`tinytodo`][]                        | Rust, Python | A simple application for managing task lists that uses Cedar for authorization demonstrating the usage of the [Cedar Rust APIs][]                                                    |
+| [`tinytodo-go`][]                     | Go, Python   | A simple application for managing task lists that uses Cedar for authorization demonstrating the usage of the [Cedar Go APIs][]                                                      |                                                                                                     |
+| [`cedar-java-hello-world`][]          | Java         | A simple application demonstrating the usage of the [Cedar Java APIs][]                                                                                                              |
+| [`cedar-rust-hello-world`][]          | Rust         | A simple application demonstrating the usage of the [Cedar Rust APIs][]                                                                                                              |
+| [`cedar-wasm-example`][]              | TypeScript   | A simple application demonstrating the usage of the [Cedar Wasm APIs][]                                                                                                              |
+| [`cedar-policy-language-in-action`][] | Cedar        | Cedar policies and schemas for the [Cedar policy language in action](https://catalog.workshops.aws/cedar-policy-language-in-action) workshop                                         |
+| [`cedar-example-use-cases`][]         | Cedar        | Cedar policies and schemas for two example applications                                                                                                                              |
+| [`oopsla2024-benchmarks`][]           | Various      | Cedar policies and schemas, along with benchmarking code and scripts, used for the performance evaluation of the [OOPSLA2024 paper on Cedar](https://dl.acm.org/doi/10.1145/3649835) |
 
 ## Security
 
@@ -21,6 +22,7 @@ See [CONTRIBUTING](CONTRIBUTING.md#security-issue-notifications) for more inform
 This project is licensed under the Apache-2.0 License.
 
 [Cedar Rust APIs]: https://docs.rs/cedar-policy/latest/cedar_policy
+[Cedar Go APIs]: https://github.com/cedar-policy/cedar-go
 [Cedar Java APIs]: https://github.com/cedar-policy/cedar-java
 [Cedar Wasm APIs]: https://github.com/cedar-policy/cedar/tree/main/cedar-wasm
 [`cedar-example-use-cases`]: ./cedar-example-use-cases
@@ -30,3 +32,4 @@ This project is licensed under the Apache-2.0 License.
 [`cedar-policy-language-in-action`]: ./cedar-policy-language-in-action
 [`oopsla2024-benchmarks`]: ./oopsla2024-benchmarks
 [`tinytodo`]: ./tinytodo
+[`tinytodo-go`]: ./tinytodo-go

tinytodo-go/README.md

@@ -0,0 +1,27 @@
+# TinyTodo-Go
+
+This is a Go implementation of [TinyTodo](../tinytodo/).
+
+It relies on [`cedar-go`](https://github.com/cedar-policy/cedar-go).
+
+## Usage
+
+TinyTodo-Go's usage is similar to [TinyTodo](../tinytodo/) - you are encouraged to use an identical [Python CLI tool](./tinytodo.py) to interact with the HTTP REST APIs offered by TinyTodo-Go (which are identical to the APIs offered by TinyTodo).
+
+To run with logging, set the environment variable `GO_LOG` to level `info`:
+
+```SHELL
+> GO_LOG=info python -i tinytodo.py
+```
+
+See [TinyTodo's README](../tinytodo/README.md) for more information.
+
+## Build
+
+You need Python3 and Go (1.22 or later).
+
+See [TinyTodo's README](../tinytodo/README.md) for more information.
+
+## Comparison with TinyTodo
+
+TinyTodo-Go is constrained by the features of [`cedar-go`](https://github.com/cedar-policy/cedar-go). Refer to [this README](https://github.com/cedar-policy/cedar-go?tab=readme-ov-file#comparison-to-the-rust-implementation) to learn about the missing features.

tinytodo-go/cmd/server/authorization.go

@@ -0,0 +1,38 @@
+package main
+
+import (
+	"fmt"
+	"github.com/cedar-policy/cedar-examples/tinytodo-go/internal/app/server/entitystore"
+	"github.com/cedar-policy/cedar-go"
+	"os"
+)
+
+const (
+	DefaultCedarPolicyFileName = "policies.cedar"
+	DefaultEntitiesFileName    = "entities.json" // this is not in the Cedar entity schema, conversion required
+)
+
+func prepareCedarPolicyEntities() (*entitystore.EntityStore, cedar.PolicySet, error) {
+
+	entitiesFile, err := os.ReadFile(DefaultEntitiesFileName)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to read EntitiesFile: %w", err)
+	}
+
+	es, err := entitystore.New(entitiesFile)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to create EntityStore: %w", err)
+	}
+
+	psFile, err := os.ReadFile(DefaultCedarPolicyFileName)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to read Cedar policy file: %w", err)
+	}
+
+	ps, err := cedar.NewPolicySet(DefaultCedarPolicyFileName, psFile)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to create Cedar policy set: %w", err)
+	}
+
+	return es, ps, nil
+}

tinytodo-go/cmd/server/log.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"github.com/cedar-policy/cedar-examples/tinytodo-go/internal/app/server"
+	"log/slog"
+	"os"
+)
+
+func prepareLogger() server.Option {
+	if logLevel := os.Getenv("GO_LOG"); logLevel != "" {
+		var level slog.Level
+		switch logLevel {
+		case slog.LevelDebug.String():
+			level = slog.LevelDebug
+		case slog.LevelInfo.String():
+			level = slog.LevelInfo
+		case slog.LevelWarn.String():
+			level = slog.LevelWarn
+		case slog.LevelError.String():
+			level = slog.LevelError
+		}
+		return server.WithLogger(
+			slog.New(
+				slog.NewTextHandler(
+					os.Stdout,
+					&slog.HandlerOptions{
+						Level: level,
+					},
+				),
+			),
+		)
+	}
+	return server.WithLogger(DefaultLogger)
+}

tinytodo-go/cmd/server/main.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"log/slog"
+	"os"
+)
+
+func main() {
+	if err := startServer(); err != nil {
+		DefaultLogger.Error("failed to start server", slog.Any("error", err))
+		os.Exit(-1)
+	}
+}

tinytodo-go/cmd/server/server.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"github.com/cedar-policy/cedar-examples/tinytodo-go/internal/app/server"
+)
+
+var (
+	DefaultLogger = server.DefaultLogger
+)
+
+// startServer starts the web server by parsing these CLI arguments:
+//
+//   - port: Port number (default 8080)
+func startServer() error {
+
+	port := flag.Int("port", 8080, "Listen port")
+	flag.Parse()
+
+	es, ps, err := prepareCedarPolicyEntities()
+	if err != nil {
+		return err
+	}
+
+	w, err := server.New(
+		fmt.Sprintf(":%d", *port),
+		es,
+		ps,
+		prepareLogger(),
+	)
+	if err != nil {
+		return err
+	}
+
+	if err := w.Serve(); err != nil {
+		return err
+	}
+
+	DefaultLogger.Info("terminating")
+	return nil
+}

tinytodo-go/entities.json

@@ -0,0 +1,66 @@
+{
+  "users": {
+    "User::\"kesha\"": {
+      "euid": "User::\"kesha\"",
+      "location": "ABC17",
+      "joblevel": 5,
+      "parents": [
+        "Application::\"TinyTodo\"",
+        "Team::\"temp\""
+      ]
+    },
+    "User::\"aaron\"": {
+      "euid": "User::\"aaron\"",
+      "location": "ABC17",
+      "joblevel": 5,
+      "parents": [
+        "Team::\"interns\"",
+        "Application::\"TinyTodo\""
+      ]
+    },
+    "User::\"emina\"": {
+      "euid": "User::\"emina\"",
+      "location": "DEF33",
+      "joblevel": 8,
+      "parents": [
+        "Application::\"TinyTodo\"",
+        "Team::\"admin\""
+      ]
+    },
+    "User::\"andrew\"": {
+      "euid": "User::\"andrew\"",
+      "location": "XYZ77",
+      "joblevel": 5,
+      "parents": [
+        "Application::\"TinyTodo\"",
+        "Team::\"admin\"",
+        "Team::\"temp\""
+      ]
+    }
+  },
+  "teams": {
+    "Team::\"temp\"": {
+      "uid": "Team::\"temp\"",
+      "parents": [
+        "Application::\"TinyTodo\""
+      ]
+    },
+    "Team::\"admin\"": {
+      "uid": "Team::\"admin\"",
+      "parents": [
+        "Application::\"TinyTodo\""
+      ]
+    },
+    "Team::\"interns\"": {
+      "uid": "Team::\"interns\"",
+      "parents": [
+        "Application::\"TinyTodo\"",
+        "Team::\"temp\""
+      ]
+    }
+  },
+  "lists": {},
+  "app": {
+    "euid": "Application::\"TinyTodo\""
+  }
+}

tinytodo-go/go.mod

@@ -0,0 +1,16 @@
+module github.com/cedar-policy/cedar-examples/tinytodo-go
+
+go 1.22
+
+require (
+	github.com/cedar-policy/cedar-go v0.0.0-20240715162045-a71e93ee6ae7
+	github.com/go-chi/chi/v5 v5.1.0
+	github.com/stretchr/testify v1.9.0
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	golang.org/x/exp v0.0.0-20240222234643-814bf88cf225 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

tinytodo-go/go.sum

@@ -0,0 +1,16 @@
+github.com/cedar-policy/cedar-go v0.0.0-20240715162045-a71e93ee6ae7 h1:3WPOmm5kgn8q5kbQc2kG97RK//GTQAp79AW7pV3pa8M=
+github.com/cedar-policy/cedar-go v0.0.0-20240715162045-a71e93ee6ae7/go.mod h1:pEgiK479O5dJfzXnTguOMm+bCplzy5rEEFPGdZKPWz4=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/go-chi/chi/v5 v5.1.0 h1:acVI1TYaD+hhedDJ3r54HyA6sExp3HfXq7QWEEY/xMw=
+github.com/go-chi/chi/v5 v5.1.0/go.mod h1:DslCQbL2OYiznFReuXYUmQ2hGd1aDpCnlMNITLSKoi8=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+golang.org/x/exp v0.0.0-20240222234643-814bf88cf225 h1:LfspQV/FYTatPTr/3HzIcmiUFH7PGP+OQ6mgDYo3yuQ=
+golang.org/x/exp v0.0.0-20240222234643-814bf88cf225/go.mod h1:CxmFvTBINI24O/j8iY7H1xHzx2i4OsyguNBmN/uPtqc=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=