go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/client/internal/common/flags.go (about)

     1  // Copyright 2015 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 common
    16  
    17  import (
    18  	"context"
    19  	"errors"
    20  	"flag"
    21  	"io"
    22  	"log"
    23  
    24  	"go.chromium.org/luci/common/logging"
    25  	"go.chromium.org/luci/common/logging/gologger"
    26  )
    27  
    28  // Flags contains values parsed from command line arguments.
    29  type Flags struct {
    30  	Quiet   bool
    31  	Verbose bool
    32  }
    33  
    34  // Init registers flags in a given flag set.
    35  func (d *Flags) Init(f *flag.FlagSet) {
    36  	f.BoolVar(&d.Quiet, "quiet", false, "Get less output")
    37  	f.BoolVar(&d.Verbose, "verbose", false, "Get more output")
    38  }
    39  
    40  // Parse applies changes specified by command line flags.
    41  func (d *Flags) Parse() error {
    42  	if !d.Verbose {
    43  		log.SetFlags(0)
    44  		log.SetOutput(io.Discard)
    45  	}
    46  	if d.Quiet && d.Verbose {
    47  		return errors.New("can't use both -quiet and -verbose")
    48  	}
    49  	return nil
    50  }
    51  
    52  // MakeLoggingContext makes a luci-go/common/logging compatible context using
    53  // gologger onto the given writer.
    54  //
    55  // The default logging level will be Info, with Warning and Debug corresponding
    56  // to quiet/verbose respectively.
    57  func (d *Flags) MakeLoggingContext(out io.Writer) context.Context {
    58  	ret := (&gologger.LoggerConfig{
    59  		Out:    out,
    60  		Format: gologger.PickStdFormat(out),
    61  	}).Use(context.Background())
    62  	if d.Quiet {
    63  		ret = logging.SetLevel(ret, logging.Warning)
    64  	} else if d.Verbose {
    65  		ret = logging.SetLevel(ret, logging.Debug)
    66  	} else {
    67  		ret = logging.SetLevel(ret, logging.Info)
    68  	}
    69  	return ret
    70  }