istio.io/istio@v0.0.0-20240520182934-d79c90f27776/pkg/log/klog.go (about)

     1  // Copyright Istio 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 log
    16  
    17  import (
    18  	goflag "flag"
    19  	"fmt"
    20  	"sync"
    21  
    22  	"github.com/spf13/pflag"
    23  	"k8s.io/klog/v2"
    24  )
    25  
    26  var (
    27  	KlogScope     = RegisterScope("klog", "")
    28  	configureKlog = sync.Once{}
    29  )
    30  
    31  // EnableKlogWithCobra enables klog to work with cobra / pflags.
    32  // k8s libraries like client-go use klog.
    33  func EnableKlogWithCobra() {
    34  	gf := klogVerboseFlag()
    35  	pflag.CommandLine.AddFlag(pflag.PFlagFromGoFlag(
    36  		&goflag.Flag{
    37  			Name:     "vklog",
    38  			Value:    gf.Value,
    39  			DefValue: gf.DefValue,
    40  			Usage:    gf.Usage + ". Like -v flag. ex: --vklog=9",
    41  		}))
    42  }
    43  
    44  // EnableKlogWithCobra enables klog to work with go flags.
    45  // k8s libraries like client-go use klog.
    46  func EnableKlogWithGoFlag() {
    47  	gf := klogVerboseFlag()
    48  	goflag.CommandLine.Var(gf.Value, "vklog", gf.Usage+". Like -v flag. ex: --vklog=9")
    49  }
    50  
    51  // isKlogVerbose returns true if klog verbosity is non-zero.
    52  func klogVerbose() bool {
    53  	gf := klogVerboseFlag()
    54  	return gf.Value.String() != "0"
    55  }
    56  
    57  var (
    58  	klogFlagSet     = &goflag.FlagSet{}
    59  	klogFlagSetOnce = sync.Once{}
    60  )
    61  
    62  // KlogVerboseFlag returns verbose flag from the klog library.
    63  // After parsing it contains the parsed verbosity value.
    64  func klogVerboseFlag() *goflag.Flag {
    65  	klogFlagSetOnce.Do(func() {
    66  		klog.InitFlags(klogFlagSet)
    67  	})
    68  	// --v= flag of klog.
    69  	return klogFlagSet.Lookup("v")
    70  }
    71  
    72  // EnableKlogWithVerbosity sets the klog verbosity directly.
    73  // When using in an application, EnableKlogWithCobra is preferred to expose a --vklog flag.
    74  func EnableKlogWithVerbosity(v int) {
    75  	_ = klogFlagSet.Set("v", fmt.Sprint(v))
    76  }