Add helper function to errors

error.go

@@ -0,0 +1,68 @@
+package ratchet
+
+import (
+	"errors"
+	"fmt"
+)
+
+const INTERNAL_ERROR_MESSAGE = "internal error"
+
+// Application error codes.
+//
+// Note: these are generic codes but map well to HTTP status codes.
+const (
+	EINTERNAL = "internal"
+	ENOTFOUND = "not_found"
+)
+
+// Error respresents an application specific-error. Application errors can be
+// unwrapped by the caller to extract out the code and message
+//
+// Any non-application error (like disk error) should be reported as an EINTERNAL
+// error and the human user should only see "Internal error" as the message.
+// These low-level internal error details should only be logged and reported to
+// the operation of the application, not the end user.
+type Error struct {
+	// Machine-readable error code.
+	Code string
+
+	// Human-readable error message.
+	Message string
+}
+
+// Error  implements the error interface. Not used by the application otherwise.
+func (e Error) Error() string {
+	return fmt.Sprintf("ratchet error: code=%s message=%s", e.Code, e.Message)
+}
+
+// ErrorCode unwraps an application error and returns its code.
+// Non-application errors always return EINTERNAL.
+func ErrorCode(err error) string {
+	var e *Error
+	if err == nil {
+		return ""
+	} else if errors.As(err, &e) {
+		return e.Code
+	}
+	return EINTERNAL
+}
+
+// ErrorMessage unwraps an application error and returns it's message.
+// Non-application errors always return "Internal error".
+func ErrorMessage(err error) string {
+	var e *Error
+	if err == nil {
+		return ""
+	} else if errors.As(err, &e) {
+		return e.Message
+	}
+	return INTERNAL_ERROR_MESSAGE
+}
+
+// Errorf is a helper function to return an Error with a given code and format
+func Errorf(code string, format string, args ...interface{}) *Error {
+	return &Error{
+		Code:    code,
+		Message: fmt.Sprintf(format, args...),
+	}
+}

error_test.go

@@ -0,0 +1,57 @@
+package ratchet
+
+import (
+	"errors"
+	"testing"
+)
+
+func AssertErrorString(t *testing.T, got, want string) {
+	t.Helper()
+	if got != want {
+		t.Errorf("Incorrect error code/message got %q want %q", got, want)
+	}
+}
+
+func TestErrorCode(t *testing.T) {
+
+	t.Run("should return empty", func(t *testing.T) {
+		got := ErrorCode(nil)
+
+		AssertErrorString(t, got, "")
+	})
+
+	t.Run("should return internal error", func(t *testing.T) {
+		want := EINTERNAL
+		got := ErrorCode(errors.New("Mock disk error"))
+
+		AssertErrorString(t, got, want)
+	})
+
+	t.Run("should return my code", func(t *testing.T) {
+		e := &Error{Code: "my_code", Message: "my_message"}
+		got := ErrorCode(e)
+
+		AssertErrorString(t, got, e.Code)
+	})
+}
+
+func TestErrorMessage(t *testing.T) {
+	t.Run("empty error should return empty string", func(t *testing.T) {
+		got := ErrorMessage(nil)
+
+		AssertErrorString(t, got, "")
+	})
+
+	t.Run("should return internal error message", func(t *testing.T) {
+		got := ErrorMessage(errors.New("Mock disk error"))
+
+		AssertErrorString(t, got, INTERNAL_ERROR_MESSAGE)
+	})
+
+	t.Run("should return application error message", func(t *testing.T) {
+		e := Errorf(ENOTFOUND, "Entity %s not found", "dirp")
+		got := ErrorMessage(e)
+
+		AssertErrorString(t, got, e.Message)
+	})
+}

user.go

@@ -0,0 +1,33 @@
+package ratchet
+
+import (
+	"context"
+	"time"
+)
+
+type User struct {
+	ID int `json:"id"`
+
+	// User prefered name and email
+	Name  string `json:"name"`
+	Email string `json:"email"`
+
+	// Randomly generated API key for use with the API
+	// "-" omits the key from serialization
+	APIKey string `json:"-"`
+
+	// Timestamps for user creatation and last update
+	CreatedAt time.Time `json:"createdAt"`
+	UpdatedAt time.Time `json:"updatedAt"`
+
+	// List of associated Oauth authentication Objects
+	// Not yet implemented
+	// Auths []*Auth `json:"auths"`
+}
+
+// UserService represents a service for managing users.
+type UserService interface {
+	// Retrieves a user by ID along with their associated auth objects
+	// Returns ENOTFOUND if user does not exist.
+	FindUserByID(ctx context.Context, id int) (*User, error)
+}