feat(daemon): add ErrorResponse to allow external error creation

client/client.go

@@ -403,26 +403,6 @@ type response struct {
 	Maintenance *Error `json:"maintenance"`
 }
 
-// Error is the real value of response.Result when an error occurs.
-type Error struct {
-	Kind    string      `json:"kind"`
-	Value   interface{} `json:"value"`
-	Message string      `json:"message"`
-
-	StatusCode int
-}
-
-func (e *Error) Error() string {
-	return e.Message
-}
-
-const (
-	ErrorKindLoginRequired     = "login-required"
-	ErrorKindSystemRestart     = "system-restart"
-	ErrorKindDaemonRestart     = "daemon-restart"
-	ErrorKindNoDefaultServices = "no-default-services"
-)
-
 func (rsp *response) err(cli *Client) error {
 	if cli != nil {
 		maintErr := rsp.Maintenance
@@ -441,7 +421,6 @@ func (rsp *response) err(cli *Client) error {
 	if err != nil || resultErr.Message == "" {
 		return fmt.Errorf("server error: %q", rsp.Status)
 	}
-	resultErr.StatusCode = rsp.StatusCode
 
 	return &resultErr
 }

client/errors.go

@@ -0,0 +1,43 @@
+// Copyright (c) 2023 Canonical Ltd
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 3 as
+// published by the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package client
+
+// Error is the real value of response.Result when an error type response occurs.
+type Error struct {
+	Message string      `json:"message"`
+	Kind    ErrorKind   `json:"kind,omitempty"`
+	Value   interface{} `json:"value,omitempty"`
+}
+
+func (e *Error) Error() string {
+	return e.Message
+}
+
+type ErrorKind string
+
+// Error kinds for use as a response result.
+const (
+	ErrorKindLoginRequired     = ErrorKind("login-required")
+	ErrorKindNoDefaultServices = ErrorKind("no-default-services")
+	ErrorKindNotFound          = ErrorKind("not-found")
+	ErrorKindPermissionDenied  = ErrorKind("permission-denied")
+	ErrorKindGenericFileError  = ErrorKind("generic-file-error")
+)
+
+// Maintenance error kinds for use only inside the maintenance field of responses.
+const (
+	ErrorKindSystemRestart = ErrorKind("system-restart")
+	ErrorKindDaemonRestart = ErrorKind("daemon-restart")
+)

client/files_test.go

@@ -360,7 +360,7 @@ func (cs *clientSuite) TestMakeDirFailsOnDirectory(c *C) {
 	clientErr, ok := err.(*client.Error)
 	c.Assert(ok, Equals, true)
 	c.Assert(clientErr.Message, Equals, "could not bar")
-	c.Assert(clientErr.Kind, Equals, "permission-denied")
+	c.Assert(clientErr.Kind, Equals, client.ErrorKindPermissionDenied)
 
 	c.Assert(cs.req.URL.Path, Equals, "/v1/files")
 	c.Assert(cs.req.Method, Equals, "POST")
@@ -517,7 +517,7 @@ func (cs *clientSuite) TestRemovePathFailsOnPath(c *C) {
 	clientErr, ok := err.(*client.Error)
 	c.Assert(ok, Equals, true)
 	c.Assert(clientErr.Message, Equals, "could not bar")
-	c.Assert(clientErr.Kind, Equals, "permission-denied")
+	c.Assert(clientErr.Kind, Equals, client.ErrorKindPermissionDenied)
 
 	c.Assert(cs.req.URL.Path, Equals, "/v1/files")
 	c.Assert(cs.req.Method, Equals, "POST")

internals/cli/cmd_mkdir_test.go

@@ -266,7 +266,7 @@ func (s *PebbleSuite) TestMkdirFailsOnDirectory(c *C) {
 	clientErr, ok := err.(*client.Error)
 	c.Assert(ok, Equals, true)
 	c.Assert(clientErr.Message, Equals, "could not bar")
-	c.Assert(clientErr.Kind, Equals, "permission-denied")
+	c.Assert(clientErr.Kind, Equals, client.ErrorKindPermissionDenied)
 
 	c.Assert(rest, HasLen, 1)
 	c.Check(s.Stdout(), Equals, "")

internals/cli/cmd_rm_test.go

@@ -144,7 +144,7 @@ func (s *PebbleSuite) TestRmFailsOnPath(c *C) {
 	clientErr, ok := err.(*client.Error)
 	c.Assert(ok, Equals, true)
 	c.Assert(clientErr.Message, Equals, "could not baz")
-	c.Assert(clientErr.Kind, Equals, "permission-denied")
+	c.Assert(clientErr.Kind, Equals, client.ErrorKindPermissionDenied)
 	c.Check(s.Stdout(), Equals, "")
 	c.Check(s.Stderr(), Equals, "")
 

internals/daemon/api_changes_test.go

@@ -25,6 +25,7 @@ import (
 
 	"gopkg.in/check.v1"
 
+	"github.com/canonical/pebble/client"
 	"github.com/canonical/pebble/internals/overlord/state"
 )
 
@@ -384,7 +385,7 @@ func (s *apiSuite) TestWaitChangeInvalidTimeout(c *check.C) {
 	c.Check(rec.Code, check.Equals, 400)
 	c.Check(rsp.Status, check.Equals, 400)
 	c.Check(rsp.Type, check.Equals, ResponseTypeError)
-	result := rsp.Result.(*errorResult)
+	result := rsp.Result.(*client.Error)
 	c.Check(result.Message, check.Matches, "invalid timeout .*")
 }
 
@@ -419,7 +420,7 @@ func (s *apiSuite) TestWaitChangeCancel(c *check.C) {
 	c.Check(rec.Code, check.Equals, 500)
 	c.Check(rsp.Status, check.Equals, 500)
 	c.Check(rsp.Type, check.Equals, ResponseTypeError)
-	result := rsp.Result.(*errorResult)
+	result := rsp.Result.(*client.Error)
 	c.Check(result.Message, check.Equals, "request cancelled")
 }
 
@@ -428,7 +429,7 @@ func (s *apiSuite) TestWaitChangeTimeout(c *check.C) {
 	c.Check(rec.Code, check.Equals, 504)
 	c.Check(rsp.Status, check.Equals, 504)
 	c.Check(rsp.Type, check.Equals, ResponseTypeError)
-	result := rsp.Result.(*errorResult)
+	result := rsp.Result.(*client.Error)
 	c.Check(result.Message, check.Matches, "timed out waiting for change .*")
 }
 
@@ -440,7 +441,7 @@ func (s *apiSuite) TestWaitChangeTimeoutCancel(c *check.C) {
 	c.Check(rec.Code, check.Equals, 500)
 	c.Check(rsp.Status, check.Equals, 500)
 	c.Check(rsp.Type, check.Equals, ResponseTypeError)
-	result := rsp.Result.(*errorResult)
+	result := rsp.Result.(*client.Error)
 	c.Check(result.Message, check.Equals, "request cancelled")
 }
 

internals/daemon/api_files.go

@@ -31,6 +31,7 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/canonical/pebble/client"
 	"github.com/canonical/pebble/internals/osutil"
 	"github.com/canonical/pebble/internals/osutil/sys"
 )
@@ -67,8 +68,8 @@ func v1GetFiles(_ *Command, req *http.Request, _ *UserState) Response {
 }
 
 type fileResult struct {
-	Path  string       `json:"path"`
-	Error *errorResult `json:"error,omitempty"`
+	Path  string        `json:"path"`
+	Error *client.Error `json:"error,omitempty"`
 }
 
 // Reading files
@@ -160,20 +161,20 @@ func readFile(path string, mw *multipart.Writer) error {
 	return nil
 }
 
-func fileErrorToResult(err error) *errorResult {
+func fileErrorToResult(err error) *client.Error {
 	if err == nil {
 		return nil
 	}
-	var kind errorKind
+	var kind client.ErrorKind
 	switch {
 	case errors.Is(err, os.ErrPermission):
-		kind = errorKindPermissionDenied
+		kind = client.ErrorKindPermissionDenied
 	case errors.Is(err, os.ErrNotExist):
-		kind = errorKindNotFound
+		kind = client.ErrorKindNotFound
 	default:
-		kind = errorKindGenericFileError
+		kind = client.ErrorKindGenericFileError
 	}
-	return &errorResult{
+	return &client.Error{
 		Kind:    kind,
 		Message: err.Error(),
 	}

internals/daemon/api_plan_test.go

@@ -21,6 +21,8 @@ import (
 
 	. "gopkg.in/check.v1"
 	"gopkg.in/yaml.v3"
+
+	"github.com/canonical/pebble/client"
 )
 
 var planLayer = `
@@ -54,7 +56,7 @@ func (s *apiSuite) TestGetPlanErrors(c *C) {
 		c.Assert(rec.Code, Equals, test.status)
 		c.Assert(rsp.Status, Equals, test.status)
 		c.Assert(rsp.Type, Equals, ResponseTypeError)
-		c.Assert(rsp.Result.(*errorResult).Message, Matches, test.message)
+		c.Assert(rsp.Result.(*client.Error).Message, Matches, test.message)
 	}
 }
 
@@ -123,7 +125,7 @@ func (s *apiSuite) TestLayersErrors(c *C) {
 		c.Assert(rec.Code, Equals, test.status)
 		c.Assert(rsp.Status, Equals, test.status)
 		c.Assert(rsp.Type, Equals, ResponseTypeError)
-		c.Assert(rsp.Result.(*errorResult).Message, Matches, test.message)
+		c.Assert(rsp.Result.(*client.Error).Message, Matches, test.message)
 	}
 }
 
@@ -195,6 +197,6 @@ func (s *apiSuite) TestLayersCombineFormatError(c *C) {
 	c.Assert(rec.Code, Equals, http.StatusBadRequest)
 	c.Assert(rsp.Status, Equals, http.StatusBadRequest)
 	c.Assert(rsp.Type, Equals, ResponseTypeError)
-	result := rsp.Result.(*errorResult)
+	result := rsp.Result.(*client.Error)
 	c.Assert(result.Message, Matches, `layer "base" must define "override" for service "dynamic"`)
 }

internals/daemon/api_services.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/canonical/x-go/strutil"
 
+	"github.com/canonical/pebble/client"
 	"github.com/canonical/pebble/internals/overlord/servstate"
 	"github.com/canonical/pebble/internals/overlord/state"
 )
@@ -88,7 +89,7 @@ func v1PostServices(c *Command, r *http.Request, _ *UserState) Response {
 		if len(services) == 0 {
 			return SyncResponse(&resp{
 				Type:   ResponseTypeError,
-				Result: &errorResult{Kind: errorKindNoDefaultServices, Message: "no default services"},
+				Result: &client.Error{Kind: client.ErrorKindNoDefaultServices, Message: "no default services"},
 				Status: 400,
 			})
 		}

internals/daemon/api_signals_test.go

@@ -22,6 +22,7 @@ import (
 
 	. "gopkg.in/check.v1"
 
+	"github.com/canonical/pebble/client"
 	"github.com/canonical/pebble/internals/overlord/servstate"
 )
 
@@ -66,7 +67,7 @@ services:
 	rec = httptest.NewRecorder()
 	rsp.ServeHTTP(rec, req)
 	c.Check(rec.Result().StatusCode, Equals, 500)
-	errResult, ok := rsp.Result.(*errorResult)
+	errResult, ok := rsp.Result.(*client.Error)
 	c.Assert(ok, Equals, true)
 	c.Assert(errResult.Message, Matches, `cannot send signal to "test1": invalid signal name "FOOBAR"`)
 
@@ -102,7 +103,7 @@ func (s *apiSuite) TestSignalsBadBody(c *C) {
 	rec := httptest.NewRecorder()
 	rsp.ServeHTTP(rec, req)
 	c.Check(rec.Result().StatusCode, Equals, 400)
-	errResult, ok := rsp.Result.(*errorResult)
+	errResult, ok := rsp.Result.(*client.Error)
 	c.Assert(ok, Equals, true)
 	c.Assert(errResult.Message, Matches, "cannot decode request body: .*")
 }
@@ -115,7 +116,7 @@ func (s *apiSuite) TestSignalsNoServices(c *C) {
 	rec := httptest.NewRecorder()
 	rsp.ServeHTTP(rec, req)
 	c.Check(rec.Result().StatusCode, Equals, 400)
-	errResult, ok := rsp.Result.(*errorResult)
+	errResult, ok := rsp.Result.(*client.Error)
 	c.Assert(ok, Equals, true)
 	c.Assert(errResult.Message, Equals, "must specify one or more services")
 }
@@ -129,7 +130,7 @@ func (s *apiSuite) TestSignalsServiceNotRunning(c *C) {
 	rec := httptest.NewRecorder()
 	rsp.ServeHTTP(rec, req)
 	c.Check(rec.Result().StatusCode, Equals, 500)
-	errResult, ok := rsp.Result.(*errorResult)
+	errResult, ok := rsp.Result.(*client.Error)
 	c.Assert(ok, Equals, true)
 	c.Assert(errResult.Message, Matches, `cannot send signal to "test1": service is not running`)
 }

internals/daemon/daemon.go

@@ -34,6 +34,7 @@ import (
 	"github.com/gorilla/mux"
 	"gopkg.in/tomb.v2"
 
+	"github.com/canonical/pebble/client"
 	"github.com/canonical/pebble/internals/logger"
 	"github.com/canonical/pebble/internals/osutil"
 	"github.com/canonical/pebble/internals/osutil/sys"
@@ -280,11 +281,11 @@ func (c *Command) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		st.Unlock()
 		switch rst {
 		case restart.RestartSystem:
-			rsp.transmitMaintenance(errorKindSystemRestart, "system is restarting")
+			rsp.transmitMaintenance(client.ErrorKindSystemRestart, "system is restarting")
 		case restart.RestartDaemon:
-			rsp.transmitMaintenance(errorKindDaemonRestart, "daemon is restarting")
+			rsp.transmitMaintenance(client.ErrorKindDaemonRestart, "daemon is restarting")
 		case restart.RestartSocket:
-			rsp.transmitMaintenance(errorKindDaemonRestart, "daemon is stopping to wait for socket activation")
+			rsp.transmitMaintenance(client.ErrorKindDaemonRestart, "daemon is stopping to wait for socket activation")
 		}
 		if rsp.Type != ResponseTypeError {
 			st.Lock()

internals/daemon/daemon_test.go

@@ -32,6 +32,7 @@ import (
 	"github.com/gorilla/mux"
 	. "gopkg.in/check.v1"
 
+	"github.com/canonical/pebble/client"
 	"github.com/canonical/pebble/internals/logger"
 	"github.com/canonical/pebble/internals/osutil"
 	"github.com/canonical/pebble/internals/overlord"
@@ -264,7 +265,7 @@ func (s *daemonSuite) TestCommandRestartingState(c *C) {
 	cmd.ServeHTTP(rec, req)
 	c.Check(rec.Code, Equals, 200)
 	var rst struct {
-		Maintenance *errorResult `json:"maintenance"`
+		Maintenance *client.Error `json:"maintenance"`
 	}
 	err = json.Unmarshal(rec.Body.Bytes(), &rst)
 	c.Assert(err, IsNil)
@@ -280,8 +281,8 @@ func (s *daemonSuite) TestCommandRestartingState(c *C) {
 	c.Check(rec.Code, Equals, 200)
 	err = json.Unmarshal(rec.Body.Bytes(), &rst)
 	c.Assert(err, IsNil)
-	c.Check(rst.Maintenance, DeepEquals, &errorResult{
-		Kind:    errorKindSystemRestart,
+	c.Check(rst.Maintenance, DeepEquals, &client.Error{
+		Kind:    client.ErrorKindSystemRestart,
 		Message: "system is restarting",
 	})
 
@@ -293,8 +294,8 @@ func (s *daemonSuite) TestCommandRestartingState(c *C) {
 	c.Check(rec.Code, Equals, 200)
 	err = json.Unmarshal(rec.Body.Bytes(), &rst)
 	c.Assert(err, IsNil)
-	c.Check(rst.Maintenance, DeepEquals, &errorResult{
-		Kind:    errorKindDaemonRestart,
+	c.Check(rst.Maintenance, DeepEquals, &client.Error{
+		Kind:    client.ErrorKindDaemonRestart,
 		Message: "daemon is restarting",
 	})
 }
@@ -1138,7 +1139,7 @@ func (s *daemonSuite) TestDegradedModeReply(c *C) {
 	rec = doTestReq(c, cmd, "POST")
 	c.Check(rec.Code, Equals, 500)
 	// verify we get the error
-	var v struct{ Result errorResult }
+	var v struct{ Result client.Error }
 	c.Assert(json.NewDecoder(rec.Body).Decode(&v), IsNil)
 	c.Check(v.Result.Message, Equals, "foo error")