go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/grpc/appstatus/status.go (about)

     1  // Copyright 2019 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package appstatus
    16  
    17  import (
    18  	"google.golang.org/grpc/codes"
    19  	"google.golang.org/grpc/status"
    20  
    21  	"go.chromium.org/luci/common/errors"
    22  )
    23  
    24  var appStatusTagKey = errors.NewTagKey("application-specific response status")
    25  
    26  // ToError converts an application-specific status to an error.
    27  func ToError(s *status.Status) error {
    28  	return Attach(s.Err(), s)
    29  }
    30  
    31  // Error returns an error with an application-specific status.
    32  // The message will be shared with the RPC client as is.
    33  func Error(code codes.Code, msg string) error {
    34  	return ToError(status.New(code, msg))
    35  }
    36  
    37  // Errorf returns an error with an application-specific status.
    38  // The message will be shared with the RPC client as is.
    39  func Errorf(code codes.Code, format string, args ...any) error {
    40  	return ToError(status.Newf(code, format, args...))
    41  }
    42  
    43  // Attach attaches an application-specific status to the error.
    44  // The status will be shared with the RPC client as is.
    45  // If err already has an application-specific status attached, panics.
    46  func Attach(err error, status *status.Status) error {
    47  	if status.Code() == codes.OK {
    48  		panic("cannot attach an OK status")
    49  	}
    50  
    51  	if _, ok := Get(err); ok {
    52  		panic("err already has an application-specific status")
    53  	}
    54  
    55  	tag := errors.TagValue{
    56  		Key:   appStatusTagKey,
    57  		Value: status,
    58  	}
    59  	return errors.Annotate(err, "attaching a status").Tag(tag).Err()
    60  }
    61  
    62  // Attachf is a shortcut for Attach(err, status.Newf(...))
    63  func Attachf(err error, code codes.Code, format string, args ...any) error {
    64  	return Attach(err, status.Newf(code, format, args...))
    65  }
    66  
    67  // Get returns an application-specific Status attached to err using this
    68  // package. If not explicitly set or if err is nil, then ok is false.
    69  func Get(err error) (st *status.Status, ok bool) {
    70  	v, ok := errors.TagValueIn(appStatusTagKey, err)
    71  	if !ok {
    72  		return nil, false
    73  	}
    74  
    75  	return v.(*status.Status), true
    76  }