collector: refactor textfile collector to avoid looping defer

Signed-off-by: Matt Layher <mdlayher@gmail.com>
This commit is contained in:
Matt Layher 2019-11-22 13:20:52 -05:00
parent c4c5f1f062
commit 177ac7f50f
1 changed files with 75 additions and 58 deletions

View File

@ -162,98 +162,115 @@ func convertMetricFamily(metricFamily *dto.MetricFamily, ch chan<- prometheus.Me
}
func (c *textFileCollector) exportMTimes(mtimes map[string]time.Time, ch chan<- prometheus.Metric) {
// Export the mtimes of the successful files.
if len(mtimes) > 0 {
// Sorting is needed for predictable output comparison in tests.
filenames := make([]string, 0, len(mtimes))
for filename := range mtimes {
filenames = append(filenames, filename)
}
sort.Strings(filenames)
if len(mtimes) == 0 {
return
}
for _, filename := range filenames {
mtime := float64(mtimes[filename].UnixNano() / 1e9)
if c.mtime != nil {
mtime = *c.mtime
}
ch <- prometheus.MustNewConstMetric(mtimeDesc, prometheus.GaugeValue, mtime, filename)
// Export the mtimes of the successful files.
// Sorting is needed for predictable output comparison in tests.
filenames := make([]string, 0, len(mtimes))
for filename := range mtimes {
filenames = append(filenames, filename)
}
sort.Strings(filenames)
for _, filename := range filenames {
mtime := float64(mtimes[filename].UnixNano() / 1e9)
if c.mtime != nil {
mtime = *c.mtime
}
ch <- prometheus.MustNewConstMetric(mtimeDesc, prometheus.GaugeValue, mtime, filename)
}
}
// Update implements the Collector interface.
func (c *textFileCollector) Update(ch chan<- prometheus.Metric) error {
error := 0.0
mtimes := map[string]time.Time{}
// Iterate over files and accumulate their metrics.
// Iterate over files and accumulate their metrics, but also track any
// parsing errors so an error metric can be reported.
var errored bool
files, err := ioutil.ReadDir(c.path)
if err != nil && c.path != "" {
log.Errorf("Error reading textfile collector directory %q: %s", c.path, err)
error = 1.0
errored = true
log.Errorf("failed to read textfile collector directory %q: %v", c.path, err)
}
mtimes := make(map[string]time.Time, len(files))
for _, f := range files {
if !strings.HasSuffix(f.Name(), ".prom") {
continue
}
path := filepath.Join(c.path, f.Name())
file, err := os.Open(path)
mtime, err := c.processFile(f.Name(), ch)
if err != nil {
log.Errorf("Error opening %q: %v", path, err)
error = 1.0
continue
}
defer file.Close()
var parser expfmt.TextParser
parsedFamilies, err := parser.TextToMetricFamilies(file)
if err != nil {
log.Errorf("Error parsing %q: %v", path, err)
error = 1.0
continue
}
if hasTimestamps(parsedFamilies) {
log.Errorf("Textfile %q contains unsupported client-side timestamps, skipping entire file", path)
error = 1.0
errored = true
log.Errorf("failed to collect textfile data from %q: %v", f.Name(), err)
continue
}
for _, mf := range parsedFamilies {
if mf.Help == nil {
help := fmt.Sprintf("Metric read from %s", path)
mf.Help = &help
}
}
// Only set this once it has been parsed and validated, so that
// a failure does not appear fresh.
stat, err := file.Stat()
if err != nil {
log.Errorf("Error stat'ing %q: %v", path, err)
error = 1.0
continue
}
mtimes[f.Name()] = stat.ModTime()
for _, mf := range parsedFamilies {
convertMetricFamily(mf, ch)
}
mtimes[f.Name()] = *mtime
}
c.exportMTimes(mtimes, ch)
// Export if there were errors.
var errVal float64
if errored {
errVal = 1.0
}
ch <- prometheus.MustNewConstMetric(
prometheus.NewDesc(
"node_textfile_scrape_error",
"1 if there was an error opening or reading a file, 0 otherwise",
nil, nil,
),
prometheus.GaugeValue, error,
prometheus.GaugeValue, errVal,
)
return nil
}
// processFile processes a single file, returning its modification time on success.
func (c *textFileCollector) processFile(name string, ch chan<- prometheus.Metric) (*time.Time, error) {
path := filepath.Join(c.path, name)
f, err := os.Open(path)
if err != nil {
return nil, fmt.Errorf("failed to open textfile data file %q: %v", path, err)
}
defer f.Close()
var parser expfmt.TextParser
families, err := parser.TextToMetricFamilies(f)
if err != nil {
return nil, fmt.Errorf("failed to parse textfile data from %q: %v", path, err)
}
if hasTimestamps(families) {
return nil, fmt.Errorf("textfile %q contains unsupported client-side timestamps, skipping entire file", path)
}
for _, mf := range families {
if mf.Help == nil {
help := fmt.Sprintf("Metric read from %s", path)
mf.Help = &help
}
}
for _, mf := range families {
convertMetricFamily(mf, ch)
}
// Only stat the file once it has been parsed and validated, so that
// a failure does not appear fresh.
stat, err := f.Stat()
if err != nil {
return nil, fmt.Errorf("failed to stat %q: %v", path, err)
}
t := stat.ModTime()
return &t, nil
}
// hasTimestamps returns true when metrics contain unsupported timestamps.
func hasTimestamps(parsedFamilies map[string]*dto.MetricFamily) bool {
for _, mf := range parsedFamilies {