gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/runsc/cmd/util/util.go (about)

     1  // Copyright 2019 The gVisor 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 util groups a bunch of common helper functions used by commands.
    16  package util
    17  
    18  import (
    19  	"encoding/json"
    20  	"fmt"
    21  	"io"
    22  	"os"
    23  	"time"
    24  
    25  	"github.com/google/subcommands"
    26  	"gvisor.dev/gvisor/pkg/log"
    27  )
    28  
    29  // ErrorLogger is where error messages should be written to. These messages are
    30  // consumed by containerd and show up to users of command line tools,
    31  // like docker/kubectl.
    32  var ErrorLogger io.Writer
    33  
    34  type jsonError struct {
    35  	Msg   string    `json:"msg"`
    36  	Level string    `json:"level"`
    37  	Time  time.Time `json:"time"`
    38  }
    39  
    40  // Writer writes to log and stdout.
    41  type Writer struct{}
    42  
    43  // Write implements io.Writer.
    44  func (i *Writer) Write(data []byte) (n int, err error) {
    45  	log.Infof("%s", data)
    46  	return os.Stdout.Write(data)
    47  }
    48  
    49  // Infof writes message to log and stdout.
    50  func Infof(format string, args ...any) {
    51  	log.Infof(format, args...)
    52  	fmt.Printf(format+"\n", args...)
    53  }
    54  
    55  // Errorf logs error to containerd log (--log), to stderr, and debug logs. It
    56  // returns subcommands.ExitFailure for convenience with subcommand.Execute()
    57  // methods:
    58  //
    59  //	return Errorf("Danger! Danger!")
    60  func Errorf(format string, args ...any) subcommands.ExitStatus {
    61  	// If runsc is being invoked by docker or cri-o, then we might not have
    62  	// access to stderr, so we log a serious-looking warning in addition to
    63  	// writing to stderr.
    64  	log.Warningf("FATAL ERROR: "+format, args...)
    65  	fmt.Fprintf(os.Stderr, format+"\n", args...)
    66  
    67  	j := jsonError{
    68  		Msg:   fmt.Sprintf(format, args...),
    69  		Level: "error",
    70  		Time:  time.Now(),
    71  	}
    72  	b, err := json.Marshal(j)
    73  	if err != nil {
    74  		panic(err)
    75  	}
    76  	if ErrorLogger != nil {
    77  		_, _ = ErrorLogger.Write(b)
    78  	}
    79  
    80  	return subcommands.ExitFailure
    81  }
    82  
    83  // Fatalf logs the same way as Errorf() does, plus *exits* the process.
    84  func Fatalf(format string, args ...any) {
    85  	Errorf(format, args...)
    86  	// Return an error that is unlikely to be used by the application.
    87  	os.Exit(128)
    88  }