textfile: Allow specifiying multiple directory globs. (prometheus#3135)

We already support reading from multiple directories though only using globs. Now we can specify them outright.

Example use case is exporting both static info on a RO FS generated during image building and traditional uses of textfiles (e.g. for R/W service metrics files) without scripting a file copy.

* keep flag name for compatibility
* clarify flag help text
* add test case (replicating the glob one)

Signed-off-by: eduarrrd <[email protected]>
Signed-off-by: Vitaly Zhuravlev <[email protected]>

Author: eduarrrd

collector/textfile.go

@@ -32,8 +32,8 @@ import (
 )
 
 var (
-	textFileDirectory = kingpin.Flag("collector.textfile.directory", "Directory to read text files with metrics from.").Default("").String()
-	mtimeDesc         = prometheus.NewDesc(
+	textFileDirectories = kingpin.Flag("collector.textfile.directory", "Directory to read text files with metrics from, supports glob matching. (repeatable)").Default("").Strings()
+	mtimeDesc           = prometheus.NewDesc(
 		"node_textfile_mtime_seconds",
 		"Unixtime mtime of textfiles successfully read.",
 		[]string{"file"},
@@ -42,7 +42,7 @@ var (
 )
 
 type textFileCollector struct {
-	path string
+	paths []string
 	// Only set for testing to get predictable output.
 	mtime  *float64
 	logger *slog.Logger
@@ -56,7 +56,7 @@ func init() {
 // in the given textfile directory.
 func NewTextFileCollector(logger *slog.Logger) (Collector, error) {
 	c := &textFileCollector{
-		path:   *textFileDirectory,
+		paths:  *textFileDirectories,
 		logger: logger,
 	}
 	return c, nil
@@ -194,11 +194,15 @@ func (c *textFileCollector) Update(ch chan<- prometheus.Metric) error {
 	metricsNamesToFiles := map[string][]string{}
 	metricsNamesToHelpTexts := map[string][2]string{}
 
-	paths, err := filepath.Glob(c.path)
-	if err != nil || len(paths) == 0 {
-		// not glob or not accessible path either way assume single
-		// directory and let os.ReadDir handle it
-		paths = []string{c.path}
+	paths := []string{}
+	for _, glob := range c.paths {
+		ps, err := filepath.Glob(glob)
+		if err != nil || len(ps) == 0 {
+			// not glob or not accessible path either way assume single
+			// directory and let os.ReadDir handle it
+			ps = []string{glob}
+		}
+		paths = append(paths, ps...)
 	}
 
 	mtimes := make(map[string]time.Time)

collector/textfile_test.go

@@ -52,75 +52,82 @@ func (a collectorAdapter) Collect(ch chan<- prometheus.Metric) {
 
 func TestTextfileCollector(t *testing.T) {
 	tests := []struct {
-		path string
-		out  string
+		paths []string
+		out   string
 	}{
 		{
-			path: "fixtures/textfile/no_metric_files",
-			out:  "fixtures/textfile/no_metric_files.out",
+			paths: []string{"fixtures/textfile/no_metric_files"},
+			out:   "fixtures/textfile/no_metric_files.out",
 		},
 		{
-			path: "fixtures/textfile/two_metric_files",
-			out:  "fixtures/textfile/two_metric_files.out",
+			paths: []string{"fixtures/textfile/two_metric_files"},
+			out:   "fixtures/textfile/two_metric_files.out",
 		},
 		{
-			path: "fixtures/textfile/nonexistent_path",
-			out:  "fixtures/textfile/nonexistent_path.out",
+			paths: []string{"fixtures/textfile/nonexistent_path"},
+			out:   "fixtures/textfile/nonexistent_path.out",
 		},
 		{
-			path: "fixtures/textfile/client_side_timestamp",
-			out:  "fixtures/textfile/client_side_timestamp.out",
+			paths: []string{"fixtures/textfile/client_side_timestamp"},
+			out:   "fixtures/textfile/client_side_timestamp.out",
 		},
 		{
-			path: "fixtures/textfile/different_metric_types",
-			out:  "fixtures/textfile/different_metric_types.out",
+			paths: []string{"fixtures/textfile/different_metric_types"},
+			out:   "fixtures/textfile/different_metric_types.out",
 		},
 		{
-			path: "fixtures/textfile/inconsistent_metrics",
-			out:  "fixtures/textfile/inconsistent_metrics.out",
+			paths: []string{"fixtures/textfile/inconsistent_metrics"},
+			out:   "fixtures/textfile/inconsistent_metrics.out",
 		},
 		{
-			path: "fixtures/textfile/histogram",
-			out:  "fixtures/textfile/histogram.out",
+			paths: []string{"fixtures/textfile/histogram"},
+			out:   "fixtures/textfile/histogram.out",
 		},
 		{
-			path: "fixtures/textfile/histogram_extra_dimension",
-			out:  "fixtures/textfile/histogram_extra_dimension.out",
+			paths: []string{"fixtures/textfile/histogram_extra_dimension"},
+			out:   "fixtures/textfile/histogram_extra_dimension.out",
 		},
 		{
-			path: "fixtures/textfile/summary",
-			out:  "fixtures/textfile/summary.out",
+			paths: []string{"fixtures/textfile/summary"},
+			out:   "fixtures/textfile/summary.out",
 		},
 		{
-			path: "fixtures/textfile/summary_extra_dimension",
-			out:  "fixtures/textfile/summary_extra_dimension.out",
+			paths: []string{"fixtures/textfile/summary_extra_dimension"},
+			out:   "fixtures/textfile/summary_extra_dimension.out",
 		},
 		{
-			path: "fixtures/textfile/*_extra_dimension",
-			out:  "fixtures/textfile/glob_extra_dimension.out",
+			paths: []string{
+				"fixtures/textfile/histogram_extra_dimension",
+				"fixtures/textfile/summary_extra_dimension",
+			},
+			out: "fixtures/textfile/glob_extra_dimension.out",
 		},
 		{
-			path: "fixtures/textfile/metrics_merge_empty_help",
-			out:  "fixtures/textfile/metrics_merge_empty_help.out",
+			paths: []string{"fixtures/textfile/*_extra_dimension"},
+			out:   "fixtures/textfile/glob_extra_dimension.out",
 		},
 		{
-			path: "fixtures/textfile/metrics_merge_no_help",
-			out:  "fixtures/textfile/metrics_merge_no_help.out",
+			paths: []string{"fixtures/textfile/metrics_merge_empty_help"},
+			out:   "fixtures/textfile/metrics_merge_empty_help.out",
 		},
 		{
-			path: "fixtures/textfile/metrics_merge_same_help",
-			out:  "fixtures/textfile/metrics_merge_same_help.out",
+			paths: []string{"fixtures/textfile/metrics_merge_no_help"},
+			out:   "fixtures/textfile/metrics_merge_no_help.out",
 		},
 		{
-			path: "fixtures/textfile/metrics_merge_different_help",
-			out:  "fixtures/textfile/metrics_merge_different_help.out",
+			paths: []string{"fixtures/textfile/metrics_merge_same_help"},
+			out:   "fixtures/textfile/metrics_merge_same_help.out",
+		},
+		{
+			paths: []string{"fixtures/textfile/metrics_merge_different_help"},
+			out:   "fixtures/textfile/metrics_merge_different_help.out",
 		},
 	}
 
 	for i, test := range tests {
 		mtime := 1.0
 		c := &textFileCollector{
-			path:   test.path,
+			paths:  test.paths,
 			mtime:  &mtime,
 			logger: slog.New(slog.NewTextHandler(io.Discard, nil)),
 		}
@@ -146,7 +153,7 @@ func TestTextfileCollector(t *testing.T) {
 		}
 
 		if string(want) != got {
-			t.Fatalf("%d.%q want:\n\n%s\n\ngot:\n\n%s", i, test.path, string(want), got)
+			t.Fatalf("%d.%q want:\n\n%s\n\ngot:\n\n%s", i, test.paths, string(want), got)
 		}
 	}
 }