github.com/m3db/m3@v1.5.0/src/m3ninx/util/uuid.go (about)

     1  // Copyright (c) 2018 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 util
    22  
    23  import (
    24  	"encoding/base64"
    25  	"errors"
    26  
    27  	"github.com/pborman/uuid"
    28  )
    29  
    30  var errUUIDForbidden = errors.New("generating UUIDs is forbidden")
    31  
    32  var encodedLen = base64.StdEncoding.EncodedLen(len(new(uuid.Array)))
    33  
    34  // NewUUIDFn is a function for creating new UUIDs.
    35  type NewUUIDFn func() ([]byte, error)
    36  
    37  // NewUUID returns a new UUID.
    38  func NewUUID() ([]byte, error) {
    39  	// TODO: V4 UUIDs are randomly generated. It would be more efficient to instead
    40  	// use time-based UUIDs so the prefixes of the UUIDs are similar. V1 UUIDs use
    41  	// the current timestamp and the server's MAC address but the latter isn't
    42  	// guaranteed to be unique since we may have multiple processes running on the
    43  	// same host. Elasticsearch uses Flake IDs which ensure uniqueness by requiring
    44  	// an initial coordination step and we may want to consider doing the same.
    45  	uuid := uuid.NewRandom()
    46  
    47  	buf := make([]byte, encodedLen)
    48  	base64.StdEncoding.Encode(buf, uuid)
    49  	return buf, nil
    50  }
    51  
    52  // NewUUIDForbidden is NewUUIDFn which always returns an error in the case that
    53  // UUIDs are forbidden.
    54  func NewUUIDForbidden() ([]byte, error) {
    55  	return nil, errUUIDForbidden
    56  }