Added echo middleware with tests (#16)

Author: nerdyslacker

README.md

@@ -1,6 +1,6 @@
 # Open Policy Agent Middleware
 
-This middleware integrates Open Policy Agent (OPA) to your http/gin/fiber app.
+This middleware integrates Open Policy Agent (OPA) to your http/gin/fiber/echo app.
 You can use it to enforce policies on endpoints.
 You can use OPA as local policy engine, or as a remote policy engine.
 
@@ -200,4 +200,46 @@ func main() {
 	})
 	app.Listen(":8080")
 }
+```
+
+## Usage with Echo
+```go
+package main
+
+import (
+	"github.com/Joffref/opa-middleware"
+	"github.com/Joffref/opa-middleware/config"
+	"github.com/labstack/echo/v4"
+)
+
+func main() {
+	e := echo.New()
+	middleware, err := opamiddleware.NewEchoMiddleware(
+		&config.Config{
+			URL:           "http://localhost:8181/",
+			Query:            "data.policy.allow",
+			ExceptedResult:   true,
+			DeniedStatusCode: 403,
+			DeniedMessage:    "Forbidden",
+		},
+		func(c echo.Context) (map[string]interface{}, error) {
+			return map[string]interface{}{
+				"path":   c.Request().URL.Path,
+				"method": c.Request().Method,
+			}, nil
+		},
+	)
+	if err != nil {
+		return
+	}
+	e.Use(middleware.Use())
+	e.GET("/ping", func(c echo.Context) error {
+		err := c.JSON(200, "pong")
+		if err != nil {
+			return err
+		}
+		return nil
+	})
+	e.Start(":8080")
+}
 ```

echo_middleware.go

@@ -0,0 +1,76 @@
+package opamiddleware
+
+import (
+	"errors"
+	"github.com/Joffref/opa-middleware/config"
+	"github.com/Joffref/opa-middleware/internal"
+	"github.com/labstack/echo/v4"
+	"net/http"
+)
+
+type EchoInputCreationMethod func(c echo.Context) (map[string]interface{}, error)
+
+type EchoMiddleware struct {
+	Config *config.Config
+	InputCreationMethod EchoInputCreationMethod `json:"binding_method,omitempty"`
+}
+
+func NewEchoMiddleware(cfg *config.Config, input EchoInputCreationMethod) (*EchoMiddleware, error) {
+	err := cfg.Validate()
+	if err != nil {
+		return nil, err
+	}
+	if input == nil {
+		if cfg.InputCreationMethod == nil {
+			return nil, errors.New("[opa-middleware-echo] InputCreationMethod must be provided")
+		}
+		input = func(c echo.Context) (map[string]interface{}, error) {
+			bind, err := cfg.InputCreationMethod(c.Request())
+			if err != nil {
+				return nil, err
+			}
+			return bind, nil
+		}
+	}
+	return &EchoMiddleware{
+		Config:              cfg,
+		InputCreationMethod: input,
+	}, nil
+}
+
+func (e *EchoMiddleware) Use() echo.MiddlewareFunc {
+	return func(next echo.HandlerFunc) echo.HandlerFunc {
+		return func(c echo.Context) error {
+			if e.Config.Debug {
+				e.Config.Logger.Printf("[opa-middleware-echo] Request received")
+			}
+			result, err := e.query(c)
+			if err != nil {
+				if e.Config.Debug {
+					e.Config.Logger.Printf("[opa-middleware-echo] Error: %s", err.Error())
+				}
+				return c.JSON(http.StatusInternalServerError, map[string]interface{}{"error": err.Error()})
+			}
+			if e.Config.Debug {
+				e.Config.Logger.Printf("[opa-middleware-echo] Result: %t", result)
+			}
+			if result != e.Config.ExceptedResult {
+				return c.JSON(e.Config.DeniedStatusCode, map[string]interface{}{"error": e.Config.DeniedMessage})
+			}
+			return next(c)
+		}
+	}
+}
+
+func (e *EchoMiddleware) query(c echo.Context) (bool, error) {
+	bind, err := e.InputCreationMethod(c)
+	if err != nil {
+		return !e.Config.ExceptedResult, err
+	}
+	if e.Config.URL != "" {
+		input := make(map[string]interface{})
+		input["input"] = bind
+		return internal.QueryURL(c.Request(), e.Config, input)
+	}
+	return internal.QueryPolicy(c.Request(), e.Config, bind)
+}

echo_middleware_test.go

@@ -0,0 +1,180 @@
+package opamiddleware
+
+import (
+	"github.com/Joffref/opa-middleware/config"
+	"github.com/labstack/echo/v4"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"testing"
+)
+
+var Test_Policy = `
+package policy
+
+default allow = false
+
+allow {
+	input.path = "/api/v1/users"
+	input.method = "GET"
+}`
+
+func TestEchoMiddleware_Query(t *testing.T) {
+	type fields struct {
+		Config *config.Config
+		InputCreationMethod   EchoInputCreationMethod
+	}
+	type args struct {
+		req *http.Request
+	}
+	tests := []struct {
+		name    string
+		fields  fields
+		args    args
+		want    bool
+		wantErr bool
+	}{
+		{
+			name: "Test EchoMiddleware_Query",
+			fields: fields{
+				Config: &config.Config{
+					Policy: Test_Policy,
+					Query:  "data.policy.allow",
+					ExceptedResult:   true,
+					DeniedStatusCode: 403,
+					DeniedMessage:    "Forbidden",
+				},
+				InputCreationMethod: func(c echo.Context) (map[string]interface{}, error) {
+					return map[string]interface{}{
+						"path":   c.Request().URL.Path,
+						"method": c.Request().Method,
+					}, nil
+				},
+			},
+			args: args{
+				req: &http.Request{
+					URL: &url.URL{
+						Path: "/api/v1/users",
+					},
+					Method: "GET",
+				},
+			},
+			want:    true,
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {		
+			e := echo.New()	
+			h := &EchoMiddleware{
+				Config: tt.fields.Config,
+				InputCreationMethod:   tt.fields.InputCreationMethod,
+			}
+			c := e.NewContext(tt.args.req, httptest.NewRecorder())
+			got, err := h.query(c)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("Query() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if got != tt.want {
+				t.Errorf("Query() got = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestEchoMiddleware_Use(t *testing.T) {
+	type fields struct {
+		Config *config.Config
+		InputCreationMethod   EchoInputCreationMethod
+	}
+	tests := []struct {
+		name   string
+		fields fields
+	}{
+		{
+			name: "Test EchoMiddleware_Use",
+			fields: fields{
+				Config: &config.Config{
+					Policy: Test_Policy,
+					Query:  "data.policy.allow",
+					ExceptedResult:   true,
+					DeniedStatusCode: 403,
+					DeniedMessage:    "Forbidden",
+				},
+				InputCreationMethod: func(c echo.Context) (map[string]interface{}, error) {
+					return map[string]interface{}{
+						"path":   c.Request().URL.Path,
+						"method": c.Request().Method,
+					}, nil
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			h := &EchoMiddleware{
+				Config: tt.fields.Config,
+				InputCreationMethod:   tt.fields.InputCreationMethod,
+			}
+			h.Use()
+		})
+	}
+}
+
+func TestNewEchoMiddleware(t *testing.T) {
+	type args struct {
+		cfg  *config.Config
+		inputCreationMethod EchoInputCreationMethod
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    *EchoMiddleware
+		wantErr bool
+	}{
+		{
+			name: "Test NewEchoMiddleware",
+			args: args{
+				cfg: &config.Config{
+					Policy: "policy",
+					Query:  "data.query",
+					ExceptedResult:   true,
+					DeniedStatusCode: 403,
+					DeniedMessage:    "Forbidden",
+				},
+				inputCreationMethod: func(c echo.Context) (map[string]interface{}, error) {
+					return map[string]interface{}{
+						"path":   c.Request().URL.Path,
+						"method": c.Request().Method,
+					}, nil
+				},
+			},
+			want: &EchoMiddleware{
+				Config: &config.Config{
+					Policy: "policy",
+					Query:  "data.query",
+					ExceptedResult:   true,
+					DeniedStatusCode: 403,
+					DeniedMessage:    "Forbidden",
+				},
+				InputCreationMethod: func(c echo.Context) (map[string]interface{}, error) {
+					return map[string]interface{}{
+						"path":   c.Request().URL.Path,
+						"method": c.Request().Method,
+					}, nil
+				},
+			},
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			_, err := NewEchoMiddleware(tt.args.cfg, tt.args.inputCreationMethod)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("NewEchoMiddleware() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+		})
+	}
+}

go.mod

@@ -5,6 +5,7 @@ go 1.18
 require (
 	github.com/gin-gonic/gin v1.9.1
 	github.com/gofiber/fiber/v2 v2.49.2
+	github.com/labstack/echo/v4 v4.11.4
 	github.com/open-policy-agent/opa v0.43.1
 	github.com/valyala/fasthttp v1.49.0
 )
@@ -27,9 +28,10 @@ require (
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/klauspost/compress v1.16.7 // indirect
 	github.com/klauspost/cpuid/v2 v2.2.4 // indirect
+	github.com/labstack/gommon v0.4.2 // indirect
 	github.com/leodido/go-urn v1.2.4 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
-	github.com/mattn/go-isatty v0.0.19 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mattn/go-runewidth v0.0.15 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
@@ -40,16 +42,17 @@ require (
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/ugorji/go/codec v1.2.11 // indirect
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
+	github.com/valyala/fasttemplate v1.2.2 // indirect
 	github.com/valyala/tcplisten v1.0.0 // indirect
 	github.com/vektah/gqlparser/v2 v2.4.6 // indirect
 	github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb // indirect
 	github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415 // indirect
 	github.com/yashtewari/glob-intersection v0.1.0 // indirect
 	golang.org/x/arch v0.3.0 // indirect
-	golang.org/x/crypto v0.14.0 // indirect
-	golang.org/x/net v0.17.0 // indirect
-	golang.org/x/sys v0.13.0 // indirect
-	golang.org/x/text v0.13.0 // indirect
+	golang.org/x/crypto v0.17.0 // indirect
+	golang.org/x/net v0.19.0 // indirect
+	golang.org/x/sys v0.15.0 // indirect
+	golang.org/x/text v0.14.0 // indirect
 	google.golang.org/protobuf v1.30.0 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect