github.com/m3db/m3@v1.5.0/src/query/graphite/common/aliasing.go (about)

     1  // Copyright (c) 2019 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 common
    22  
    23  import (
    24  	"fmt"
    25  	"regexp"
    26  	"strconv"
    27  
    28  	"github.com/m3db/m3/src/query/graphite/ts"
    29  	"github.com/m3db/m3/src/x/errors"
    30  )
    31  
    32  var (
    33  	backReferenceRe = regexp.MustCompile(`\\\d+`)
    34  )
    35  
    36  // Alias takes one metric or a wildcard seriesList and a string in quotes.
    37  // Prints the string instead of the metric name in the legend.
    38  func Alias(_ *Context, series ts.SeriesList, a string) (ts.SeriesList, error) {
    39  	renamed := make([]*ts.Series, series.Len())
    40  	for i := range series.Values {
    41  		renamed[i] = series.Values[i].RenamedTo(a)
    42  	}
    43  	series.Values = renamed
    44  	return series, nil
    45  }
    46  
    47  // AliasSub runs series names through a regex search/replace.
    48  func AliasSub(_ *Context, input ts.SeriesList, search, replace string) (ts.SeriesList, error) {
    49  	regex, err := regexp.Compile(search)
    50  	if err != nil {
    51  		return ts.NewSeriesList(), err
    52  	}
    53  
    54  	output := make([]*ts.Series, input.Len())
    55  	for idx, series := range input.Values {
    56  		name := series.Name()
    57  		if submatches := regex.FindStringSubmatch(name); submatches == nil {
    58  			// if the pattern doesn't match, we don't change the series name.
    59  			output[idx] = series
    60  		} else {
    61  			// go regexp package doesn't support back-references, so we need to work around it.
    62  			newName := regex.ReplaceAllString(name, replace)
    63  			newName = backReferenceRe.ReplaceAllStringFunc(newName, func(matched string) string {
    64  				index, retErr := strconv.Atoi(matched[1:])
    65  				if retErr != nil {
    66  					err = retErr
    67  					return ""
    68  				}
    69  				if index >= len(submatches) {
    70  					err = errors.NewInvalidParamsError(fmt.Errorf("invalid group reference in %s", replace))
    71  					return ""
    72  				}
    73  				return submatches[index]
    74  			})
    75  			if err != nil {
    76  				return ts.NewSeriesList(), err
    77  			}
    78  			output[idx] = series.RenamedTo(newName)
    79  		}
    80  	}
    81  
    82  	input.Values = output
    83  	return input, nil
    84  }