documentation/examples/remote_storage/remote_storage_adapter/graphite/escape.go
func escape(tv model.LabelValue) string {
	length := len(tv)
	result := bytes.NewBuffer(make([]byte, 0, length))
	for i := 0; i < length; i++ {
		b := tv[i]
		switch {
		// . is reserved by graphite, % is used to escape other bytes.
		case b == '.' || b == '%' || b == '/' || b == '=':
			fmt.Fprintf(result, "%%%X", b)
		// These symbols are ok only if backslash escaped.
		case strings.IndexByte(symbols, b) != -1:
			result.WriteString("\\" + string(b))
		// These are all fine.
		case strings.IndexByte(printables, b) != -1:
			result.WriteByte(b)
		// Defaults to percent-encoding.
		default:
			fmt.Fprintf(result, "%%%X", b)
		}
	}
	return result.String()
}
func escape(tv model.LabelValue) string {
	length := len(tv)
	result := bytes.NewBuffer(make([]byte, 0, length))
	for i := 0; i < length; i++ {
		b := tv[i]
		switch {
		// . is reserved by graphite, % is used to escape other bytes.
		case b == '.' || b == '%' || b == '/' || b == '=':
			fmt.Fprintf(result, "%%%X", b)
		// These symbols are ok only if backslash escaped.
		case strings.IndexByte(symbols, b) != -1:
			result.WriteString("\\" + string(b))
		// These are all fine.
		case strings.IndexByte(printables, b) != -1:
			result.WriteByte(b)
		// Defaults to percent-encoding.
		default:
			fmt.Fprintf(result, "%%%X", b)
		}
	}
	return result.String()
}
func escape ( tv model . LabelValue ) string { length := len ( tv ) result := bytes . NewBuffer ( make ( [ ] byte , 0 , length ) ) for i := 0 ; i < length ; i ++ { b := tv [ i ] switch { // . is reserved by graphite, % is used to escape other bytes. case b == '.' || b == '%' || b == '/' || b == '=' : fmt . Fprintf ( result , " " , b ) // These symbols are ok only if backslash escaped. case strings . IndexByte ( symbols , b ) != - 1 : result . WriteString ( " \\ " + string ( b ) ) // These are all fine. case strings . IndexByte ( printables , b ) != - 1 : result . WriteByte ( b ) // Defaults to percent-encoding. default : fmt . Fprintf ( result , " " , b ) } } return result . String ( ) }
// Graphite doesn't support tags, so label names and values must be
// encoded into the metric path. The list of characters that are usable
// with Graphite is rather fuzzy. One 'source of truth' might be the grammar
// used to parse requests in the webapp:
// https://github.com/graphite-project/graphite-web/blob/master/webapp/graphite/render/grammar.py#L83
// The list of valid symbols is defined as:
//   legal = printables - symbols + escaped(symbols)
//
// The default storage backend for Graphite (whisper) stores data
// in filenames, so we also need to use only valid filename characters.
// Fortunately on UNIX only '/' isn't, and Windows is completely unsupported
// by Graphite: http://graphite.readthedocs.org/en/latest/install.html#windows-users
// escape escapes a model.LabelValue into runes allowed in Graphite. The runes
// allowed in Graphite are all single-byte. This function encodes the arbitrary
// byte sequence found in this TagValue in way very similar to the traditional
// percent-encoding (https://en.wikipedia.org/wiki/Percent-encoding):
//
// - The string that underlies TagValue is scanned byte by byte.
//
// - If a byte represents a legal Graphite rune with the exception of '%', '/',
//   '=' and '.', that byte is directly copied to the resulting byte slice.
//   % is used for percent-encoding of other bytes.
//   / is not usable in filenames.
//   = is used when generating the path to associate values to labels.
//   . already means something for Graphite and thus can't be used in a value.
//
// - If the byte is any of (){},=.'"\, then a '\' will be prepended to it. We
//   do not percent-encode them since they are explicitly usable in this
//   way in Graphite.
//
// - All other bytes are replaced by '%' followed by two bytes containing the
//   uppercase ASCII representation of their hexadecimal value.
//
// This encoding allows to save arbitrary Go strings in Graphite. That's
// required because Prometheus label values can contain anything. Using
// percent encoding makes it easy to unescape, even in javascript.
//
// Examples:
//
// "foo-bar-42" -> "foo-bar-42"
//
// "foo_bar%42" -> "foo_bar%2542"
//
// "http://example.org:8080" -> "http:%2F%2Fexample%2Eorg:8080"
//
// "Björn's email: bjoern@soundcloud.com" ->
// "Bj%C3%B6rn's%20email:%20bjoern%40soundcloud.com"
//
// "日" -> "%E6%97%A5"
Graphite doesn t support tags so label names and values must be encoded into the metric path . The list of characters that are usable with Graphite is rather fuzzy . One source of truth might be the grammar used to parse requests in the webapp : https : // github . com / graphite - project / graphite - web / blob / master / webapp / graphite / render / grammar . py#L83 The list of valid symbols is defined as : legal = printables - symbols + escaped ( symbols ) The default storage backend for Graphite ( whisper ) stores data in filenames so we also need to use only valid filename characters . Fortunately on UNIX only / isn t and Windows is completely unsupported by Graphite : http : // graphite . readthedocs . org / en / latest / install . html#windows - users escape escapes a model . LabelValue into runes allowed in Graphite . The runes allowed in Graphite are all single - byte . This function encodes the arbitrary byte sequence found in this TagValue in way very similar to the traditional percent - encoding ( https : // en . wikipedia . org / wiki / Percent - encoding ) : - The string that underlies TagValue is scanned byte by byte . - If a byte represents a legal Graphite rune with the exception of % / = and . that byte is directly copied to the resulting byte slice . % is used for percent - encoding of other bytes . / is not usable in filenames . = is used when generating the path to associate values to labels . . already means something for Graphite and thus can t be used in a value . - If the byte is any of () {} = . \ then a \ will be prepended to it . We do not percent - encode them since they are explicitly usable in this way in Graphite . - All other bytes are replaced by % followed by two bytes containing the uppercase ASCII representation of their hexadecimal value . This encoding allows to save arbitrary Go strings in Graphite . That s required because Prometheus label values can contain anything . Using percent encoding makes it easy to unescape even in javascript . Examples : foo - bar - 42 - > foo - bar - 42 foo_bar%42 - > foo_bar%2542 http : // example . org : 8080 - > http : %2F%2Fexample%2Eorg : 8080 Björn s email : bjoern