forked from mirrors/statsd_exporter
55 lines
1.5 KiB
Go
55 lines
1.5 KiB
Go
package fsm
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import (
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"fmt"
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"strconv"
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"strings"
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)
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type templateFormatter struct {
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captureIndexes []int
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captureCount int
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fmtString string
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}
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func newTemplateFormatter(valueExpr string, captureCount int) *templateFormatter {
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matches := templateReplaceCaptureRE.FindAllStringSubmatch(valueExpr, -1)
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if len(matches) == 0 {
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// if no regex reference found, keep it as it is
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return &templateFormatter{captureCount: 0, fmtString: valueExpr}
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}
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var indexes []int
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valueFormatter := valueExpr
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for _, match := range matches {
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idx, err := strconv.Atoi(match[len(match)-1])
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if err != nil || idx > captureCount || idx < 1 {
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// if index larger than captured count or using unsupported named capture group,
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// replace with empty string
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valueFormatter = strings.Replace(valueFormatter, match[0], "", -1)
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} else {
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valueFormatter = strings.Replace(valueFormatter, match[0], "%s", -1)
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// note: the regex reference variable $? starts from 1
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indexes = append(indexes, idx-1)
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}
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}
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return &templateFormatter{
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captureIndexes: indexes,
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captureCount: len(indexes),
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fmtString: valueFormatter,
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}
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}
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func (formatter *templateFormatter) format(captures map[int]string) string {
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if formatter.captureCount == 0 {
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// no label substitution, keep as it is
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return formatter.fmtString
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} else {
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indexes := formatter.captureIndexes
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vargs := make([]interface{}, formatter.captureCount)
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for i, idx := range indexes {
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vargs[i] = captures[idx]
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}
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return fmt.Sprintf(formatter.fmtString, vargs...)
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}
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}
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