Add helper function to indicate the error cause

Signed-off-by: Penghui Liao <liaoishere@gmail.com>

const.gen.go

@@ -1963,3 +1963,193 @@ const (
 	StreamEventError    StreamEventType = 4
 	StreamEventHangup   StreamEventType = 8
 )
+
+// ErrorLevel as declared in libvirt/virterror.h:44
+type ErrorLevel int32
+
+// ErrorLevel enumeration from libvirt/virterror.h:44
+const (
+	ErrNone    ErrorLevel = iota
+	ErrWarning ErrorLevel = 1
+	ErrError   ErrorLevel = 2
+)
+
+// ErrorDomain as declared in libvirt/virterror.h:139
+type ErrorDomain int32
+
+// ErrorDomain enumeration from libvirt/virterror.h:139
+const (
+	FromNone           ErrorDomain = iota
+	FromXen            ErrorDomain = 1
+	FromXend           ErrorDomain = 2
+	FromXenstore       ErrorDomain = 3
+	FromSexpr          ErrorDomain = 4
+	FromXML            ErrorDomain = 5
+	FromDom            ErrorDomain = 6
+	FromRPC            ErrorDomain = 7
+	FromProxy          ErrorDomain = 8
+	FromConf           ErrorDomain = 9
+	FromQemu           ErrorDomain = 10
+	FromNet            ErrorDomain = 11
+	FromTest           ErrorDomain = 12
+	FromRemote         ErrorDomain = 13
+	FromOpenvz         ErrorDomain = 14
+	FromXenxm          ErrorDomain = 15
+	FromStatsLinux     ErrorDomain = 16
+	FromLxc            ErrorDomain = 17
+	FromStorage        ErrorDomain = 18
+	FromNetwork        ErrorDomain = 19
+	FromDomain         ErrorDomain = 20
+	FromUml            ErrorDomain = 21
+	FromNodedev        ErrorDomain = 22
+	FromXenInotify     ErrorDomain = 23
+	FromSecurity       ErrorDomain = 24
+	FromVbox           ErrorDomain = 25
+	FromInterface      ErrorDomain = 26
+	FromOne            ErrorDomain = 27
+	FromEsx            ErrorDomain = 28
+	FromPhyp           ErrorDomain = 29
+	FromSecret         ErrorDomain = 30
+	FromCPU            ErrorDomain = 31
+	FromXenapi         ErrorDomain = 32
+	FromNwfilter       ErrorDomain = 33
+	FromHook           ErrorDomain = 34
+	FromDomainSnapshot ErrorDomain = 35
+	FromAudit          ErrorDomain = 36
+	FromSysinfo        ErrorDomain = 37
+	FromStreams        ErrorDomain = 38
+	FromVmware         ErrorDomain = 39
+	FromEvent          ErrorDomain = 40
+	FromLibxl          ErrorDomain = 41
+	FromLocking        ErrorDomain = 42
+	FromHyperv         ErrorDomain = 43
+	FromCapabilities   ErrorDomain = 44
+	FromURI            ErrorDomain = 45
+	FromAuth           ErrorDomain = 46
+	FromDbus           ErrorDomain = 47
+	FromParallels      ErrorDomain = 48
+	FromDevice         ErrorDomain = 49
+	FromSSH            ErrorDomain = 50
+	FromLockspace      ErrorDomain = 51
+	FromInitctl        ErrorDomain = 52
+	FromIdentity       ErrorDomain = 53
+	FromCgroup         ErrorDomain = 54
+	FromAccess         ErrorDomain = 55
+	FromSystemd        ErrorDomain = 56
+	FromBhyve          ErrorDomain = 57
+	FromCrypto         ErrorDomain = 58
+	FromFirewall       ErrorDomain = 59
+	FromPolkit         ErrorDomain = 60
+	FromThread         ErrorDomain = 61
+	FromAdmin          ErrorDomain = 62
+	FromLogging        ErrorDomain = 63
+	FromXenxl          ErrorDomain = 64
+	FromPerf           ErrorDomain = 65
+	FromLibssh         ErrorDomain = 66
+)
+
+// ErrorNumber as declared in libvirt/virterror.h:322
+type ErrorNumber int32
+
+// ErrorNumber enumeration from libvirt/virterror.h:322
+const (
+	ErrOk                    ErrorNumber = iota
+	ErrInternalError         ErrorNumber = 1
+	ErrNoMemory              ErrorNumber = 2
+	ErrNoSupport             ErrorNumber = 3
+	ErrUnknownHost           ErrorNumber = 4
+	ErrNoConnect             ErrorNumber = 5
+	ErrInvalidConn           ErrorNumber = 6
+	ErrInvalidDomain         ErrorNumber = 7
+	ErrInvalidArg            ErrorNumber = 8
+	ErrOperationFailed       ErrorNumber = 9
+	ErrGetFailed             ErrorNumber = 10
+	ErrPostFailed            ErrorNumber = 11
+	ErrHTTPError             ErrorNumber = 12
+	ErrSexprSerial           ErrorNumber = 13
+	ErrNoXen                 ErrorNumber = 14
+	ErrXenCall               ErrorNumber = 15
+	ErrOsType                ErrorNumber = 16
+	ErrNoKernel              ErrorNumber = 17
+	ErrNoRoot                ErrorNumber = 18
+	ErrNoSource              ErrorNumber = 19
+	ErrNoTarget              ErrorNumber = 20
+	ErrNoName                ErrorNumber = 21
+	ErrNoOs                  ErrorNumber = 22
+	ErrNoDevice              ErrorNumber = 23
+	ErrNoXenstore            ErrorNumber = 24
+	ErrDriverFull            ErrorNumber = 25
+	ErrCallFailed            ErrorNumber = 26
+	ErrXMLError              ErrorNumber = 27
+	ErrDomExist              ErrorNumber = 28
+	ErrOperationDenied       ErrorNumber = 29
+	ErrOpenFailed            ErrorNumber = 30
+	ErrReadFailed            ErrorNumber = 31
+	ErrParseFailed           ErrorNumber = 32
+	ErrConfSyntax            ErrorNumber = 33
+	ErrWriteFailed           ErrorNumber = 34
+	ErrXMLDetail             ErrorNumber = 35
+	ErrInvalidNetwork        ErrorNumber = 36
+	ErrNetworkExist          ErrorNumber = 37
+	ErrSystemError           ErrorNumber = 38
+	ErrRPC                   ErrorNumber = 39
+	ErrGnutlsError           ErrorNumber = 40
+	WarNoNetwork             ErrorNumber = 41
+	ErrNoDomain              ErrorNumber = 42
+	ErrNoNetwork             ErrorNumber = 43
+	ErrInvalidMac            ErrorNumber = 44
+	ErrAuthFailed            ErrorNumber = 45
+	ErrInvalidStoragePool    ErrorNumber = 46
+	ErrInvalidStorageVol     ErrorNumber = 47
+	WarNoStorage             ErrorNumber = 48
+	ErrNoStoragePool         ErrorNumber = 49
+	ErrNoStorageVol          ErrorNumber = 50
+	WarNoNode                ErrorNumber = 51
+	ErrInvalidNodeDevice     ErrorNumber = 52
+	ErrNoNodeDevice          ErrorNumber = 53
+	ErrNoSecurityModel       ErrorNumber = 54
+	ErrOperationInvalid      ErrorNumber = 55
+	WarNoInterface           ErrorNumber = 56
+	ErrNoInterface           ErrorNumber = 57
+	ErrInvalidInterface      ErrorNumber = 58
+	ErrMultipleInterfaces    ErrorNumber = 59
+	WarNoNwfilter            ErrorNumber = 60
+	ErrInvalidNwfilter       ErrorNumber = 61
+	ErrNoNwfilter            ErrorNumber = 62
+	ErrBuildFirewall         ErrorNumber = 63
+	WarNoSecret              ErrorNumber = 64
+	ErrInvalidSecret         ErrorNumber = 65
+	ErrNoSecret              ErrorNumber = 66
+	ErrConfigUnsupported     ErrorNumber = 67
+	ErrOperationTimeout      ErrorNumber = 68
+	ErrMigratePersistFailed  ErrorNumber = 69
+	ErrHookScriptFailed      ErrorNumber = 70
+	ErrInvalidDomainSnapshot ErrorNumber = 71
+	ErrNoDomainSnapshot      ErrorNumber = 72
+	ErrInvalidStream         ErrorNumber = 73
+	ErrArgumentUnsupported   ErrorNumber = 74
+	ErrStorageProbeFailed    ErrorNumber = 75
+	ErrStoragePoolBuilt      ErrorNumber = 76
+	ErrSnapshotRevertRisky   ErrorNumber = 77
+	ErrOperationAborted      ErrorNumber = 78
+	ErrAuthCancelled         ErrorNumber = 79
+	ErrNoDomainMetadata      ErrorNumber = 80
+	ErrMigrateUnsafe         ErrorNumber = 81
+	ErrOverflow              ErrorNumber = 82
+	ErrBlockCopyActive       ErrorNumber = 83
+	ErrOperationUnsupported  ErrorNumber = 84
+	ErrSSH                   ErrorNumber = 85
+	ErrAgentUnresponsive     ErrorNumber = 86
+	ErrResourceBusy          ErrorNumber = 87
+	ErrAccessDenied          ErrorNumber = 88
+	ErrDbusService           ErrorNumber = 89
+	ErrStorageVolExist       ErrorNumber = 90
+	ErrCPUIncompatible       ErrorNumber = 91
+	ErrXMLInvalidSchema      ErrorNumber = 92
+	ErrMigrateFinishOk       ErrorNumber = 93
+	ErrAuthUnavailable       ErrorNumber = 94
+	ErrNoServer              ErrorNumber = 95
+	ErrNoClient              ErrorNumber = 96
+	ErrAgentUnsynced         ErrorNumber = 97
+	ErrLibssh                ErrorNumber = 98
+)

libvirt.yml

@@ -30,6 +30,7 @@ PARSER:
     IncludePaths: [./lv_source/include]
     SourcesPaths:
         - libvirt/libvirt.h
+        - libvirt/virterror.h
 
 TRANSLATOR:
     ConstRules:
@@ -52,6 +53,9 @@ TRANSLATOR:
             - {action: replace, from: "Uri([A-Z]|$)", to: "URI$1"}
             - {action: replace, from: "Vcpu([A-Z]|$)", to: "VCPU$1"}
             - {action: replace, from: "Xml([A-Z]|$)", to: "XML$1"}
+            - {action: replace, from: "Rpc([A-Z]|$)", to: "RPC$1"}
+            - {action: replace, from: "Ssh([A-Z]|$)", to: "SSH$1"}
+            - {action: replace, from: "Http([A-Z]|$)", to: "HTTP$1"}
         const:
             - {action: accept, from: "^VIR_"}
             # Special case to prevent a collision with a type:

rpc.go

@@ -18,6 +18,7 @@ import (
 	"bytes"
 	"encoding/binary"
 	"errors"
+	"fmt"
 	"io"
 	"strings"
 	"sync/atomic"
@@ -113,6 +114,28 @@ type libvirtError struct {
 	Level    uint32
 }
 
+func (e libvirtError) Error() string {
+	return fmt.Sprintf("%s, code: %d, domain id: %d", e.Message, e.Code, e.DomainID)
+}
+
+func checkError(err error, expectedError ErrorNumber) bool {
+	e, ok := err.(libvirtError)
+	if ok {
+		return e.Code == uint32(expectedError)
+	}
+	return false
+}
+
+// ErrIsNotFound detects libvirt's ERR_NO_DOMAIN.
+func ErrIsNotFound(err error) bool {
+	return checkError(err, ErrNoDomain)
+}
+
+// ErrIsOK detects libvirt's ERR_OK.
+func ErrIsOK(err error) bool {
+	return checkError(err, ErrOk)
+}
+
 // listen processes incoming data and routes
 // responses to their respective callback handler.
 func (l *Libvirt) listen() {
@@ -329,7 +352,7 @@ func decodeError(buf []byte) error {
 		return ErrUnsupported
 	}
 
-	return errors.New(e.Message)
+	return e
 }
 
 // decodeEvent extracts an event from the given byte slice.

rpc_test.go

@@ -89,7 +89,7 @@ var (
 	}
 
 	testErrorMessage = []byte{
-		0x00, 0x00, 0x00, 0x37, // code
+		0x00, 0x00, 0x00, 0x37, // code (55, ErrOperationInvalid)
 		0x00, 0x00, 0x00, 0x0a, // domain id
 
 		// message ("Requested operation is not valid: domain is not running")
@@ -106,6 +106,25 @@ var (
 		0x00, 0x00, 0x00, 0x02,
 	}
 
+	testErrorNotFoundMessage = []byte{
+		0x00, 0x00, 0x00, 0x2a, // code (42 ErrDoDmain)
+		0x00, 0x00, 0x00, 0x0a, // domain id
+
+		// message
+		0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x38,
+		0x44, 0x6f, 0x6d, 0x61, 0x69, 0x6e, 0x20, 0x6e,
+		0x6f, 0x74, 0x20, 0x66, 0x6f, 0x75, 0x6e, 0x64,
+		0x3a, 0x20, 0x6e, 0x6f, 0x20, 0x64, 0x6f, 0x6d,
+		0x61, 0x69, 0x6e, 0x20, 0x77, 0x69, 0x74, 0x68,
+		0x20, 0x6d, 0x61, 0x74, 0x63, 0x68, 0x69, 0x6e,
+		0x67, 0x20, 0x6e, 0x61, 0x6d, 0x65, 0x20, 0x27,
+		0x74, 0x65, 0x73, 0x74, 0x2d, 0x2d, 0x2d, 0x27,
+		0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00,
+
+		// error level
+		0x00, 0x00, 0x00, 0x01,
+	}
+
 	testDomain = &Domain{
 		Name: "test-domain",
 		UUID: testUUID,
@@ -204,11 +223,24 @@ func TestDecodeEvent(t *testing.T) {
 }
 
 func TestDecodeError(t *testing.T) {
-	expected := "Requested operation is not valid: domain is not running"
+	expectedMsg := "Requested operation is not valid: domain is not running"
+	expectedCode := ErrOperationInvalid
 
 	err := decodeError(testErrorMessage)
-	if err.Error() != expected {
+	e := err.(libvirtError)
-		t.Errorf("expected error %s, got %s", expected, err.Error())
+	if e.Message != expectedMsg {
+		t.Errorf("expected error message %s, got %s", expectedMsg, err.Error())
+	}
+	if e.Code != uint32(expectedCode) {
+		t.Errorf("expected code %d, got %d", expectedCode, e.Code)
+	}
+}
+
+func TestErrNotFound(t *testing.T) {
+	err := decodeError(testErrorNotFoundMessage)
+	ok := ErrIsNotFound(err)
+	if !ok {
+		t.Errorf("expected true, got %t", ok)
 	}
 }