github.com/m3db/m3@v1.5.0/src/x/clock/options.go (about)

     1  // Copyright (c) 2016 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package clock
    22  
    23  import (
    24  	"fmt"
    25  	"os"
    26  	"strconv"
    27  	"time"
    28  )
    29  
    30  const (
    31  	panicOnDefaultClockEnvVar = "PANIC_ON_DEFAULT_CLOCK"
    32  )
    33  
    34  type options struct {
    35  	nowFn           NowFn
    36  	maxPositiveSkew time.Duration
    37  	maxNegativeSkew time.Duration
    38  }
    39  
    40  // NewOptions creates new clock options.
    41  func NewOptions() Options {
    42  	if value, ok := os.LookupEnv(panicOnDefaultClockEnvVar); ok {
    43  		if shouldPanic, err := strconv.ParseBool(value); err == nil && shouldPanic {
    44  			return &options{
    45  				nowFn: func() time.Time {
    46  					panic(fmt.Sprintf("default clock used with %s=true", panicOnDefaultClockEnvVar))
    47  				},
    48  			}
    49  		}
    50  	}
    51  
    52  	return &options{
    53  		nowFn: time.Now,
    54  	}
    55  }
    56  
    57  func (o *options) SetNowFn(value NowFn) Options {
    58  	opts := *o
    59  	opts.nowFn = value
    60  	return &opts
    61  }
    62  
    63  func (o *options) NowFn() NowFn {
    64  	return o.nowFn
    65  }
    66  
    67  func (o *options) SetMaxPositiveSkew(value time.Duration) Options {
    68  	opts := *o
    69  	opts.maxPositiveSkew = value
    70  	return &opts
    71  }
    72  
    73  func (o *options) MaxPositiveSkew() time.Duration {
    74  	return o.maxPositiveSkew
    75  }
    76  
    77  func (o *options) SetMaxNegativeSkew(value time.Duration) Options {
    78  	opts := *o
    79  	opts.maxNegativeSkew = value
    80  	return &opts
    81  }
    82  
    83  func (o *options) MaxNegativeSkew() time.Duration {
    84  	return o.maxNegativeSkew
    85  }