cc-metric-collector/pkg/hostlist/hostlist.go
2022-11-29 14:04:31 +01:00

126 lines
3.1 KiB
Go

package hostlist
import (
"fmt"
"regexp"
"sort"
"strconv"
"strings"
)
func Expand(in string) (result []string, err error) {
// Create ranges regular expression
reStNumber := "[[:digit:]]+"
reStRange := reStNumber + "-" + reStNumber
reStOptionalNumberOrRange := "(" + reStNumber + ",|" + reStRange + ",)*"
reStNumberOrRange := "(" + reStNumber + "|" + reStRange + ")"
reStBraceLeft := "[[]"
reStBraceRight := "[]]"
reStRanges := reStBraceLeft +
reStOptionalNumberOrRange +
reStNumberOrRange +
reStBraceRight
reRanges := regexp.MustCompile(reStRanges)
// Create host list regular expression
reStDNSChars := "[a-zA-Z0-9-]+"
reStPrefix := "^(" + reStDNSChars + ")"
reStOptionalSuffix := "(" + reStDNSChars + ")?"
re := regexp.MustCompile(reStPrefix + "([[][0-9,-]+[]])?" + reStOptionalSuffix)
// Remove all delimiters from the input
in = strings.TrimLeft(in, ", ")
for len(in) > 0 {
if v := re.FindStringSubmatch(in); v != nil {
// Remove matched part from the input
lenPrefix := len(v[0])
in = in[lenPrefix:]
// Remove all delimiters from the input
in = strings.TrimLeft(in, ", ")
// matched prefix, range and suffix
hlPrefix := v[1]
hlRanges := v[2]
hlSuffix := v[3]
// Single node without ranges
if hlRanges == "" {
result = append(result, hlPrefix)
continue
}
// Node with ranges
if v := reRanges.FindStringSubmatch(hlRanges); v != nil {
// Remove braces
hlRanges = hlRanges[1 : len(hlRanges)-1]
// Split host ranges at ,
for _, hlRange := range strings.Split(hlRanges, ",") {
// Split host range at -
RangeStartEnd := strings.Split(hlRange, "-")
// Range is only a single number
if len(RangeStartEnd) == 1 {
result = append(result, hlPrefix+RangeStartEnd[0]+hlSuffix)
continue
}
// Range has a start and an end
widthRangeStart := len(RangeStartEnd[0])
widthRangeEnd := len(RangeStartEnd[1])
iStart, _ := strconv.ParseUint(RangeStartEnd[0], 10, 64)
iEnd, _ := strconv.ParseUint(RangeStartEnd[1], 10, 64)
if iStart > iEnd {
return nil, fmt.Errorf("single range start is greater than end: %s", hlRange)
}
// Create print format string for range numbers
doPadding := widthRangeStart == widthRangeEnd
widthPadding := widthRangeStart
var formatString string
if doPadding {
formatString = "%0" + fmt.Sprint(widthPadding) + "d"
} else {
formatString = "%d"
}
formatString = hlPrefix + formatString + hlSuffix
// Add nodes from this range
for i := iStart; i <= iEnd; i++ {
result = append(result, fmt.Sprintf(formatString, i))
}
}
} else {
return nil, fmt.Errorf("not at hostlist range: %s", hlRanges)
}
} else {
return nil, fmt.Errorf("not a hostlist: %s", in)
}
}
if result != nil {
// sort
sort.Strings(result)
// uniq
previous := 1
for current := 1; current < len(result); current++ {
if result[current-1] != result[current] {
if previous != current {
result[previous] = result[current]
}
previous++
}
}
result = result[:previous]
}
return
}