From 02532771213fcb024608043d7b1e514c1a80c2da Mon Sep 17 00:00:00 2001 From: Wei He Date: Tue, 2 Jun 2020 17:52:00 +0900 Subject: [PATCH] Add flag to aggr ipvs metrics to avoid high cardinality metrics (#1709) Fixes #1708 Signed-off-by: Wing924 --- ...vs_result_lbs_local_address_local_port.txt | 33 +++ .../fixtures/ip_vs_result_lbs_local_port.txt | 27 +++ collector/fixtures/ip_vs_result_lbs_none.txt | 24 ++ collector/ipvs_linux.go | 121 +++++++-- collector/ipvs_linux_test.go | 229 +++++++++++++----- 5 files changed, 349 insertions(+), 85 deletions(-) create mode 100644 collector/fixtures/ip_vs_result_lbs_local_address_local_port.txt create mode 100644 collector/fixtures/ip_vs_result_lbs_local_port.txt create mode 100644 collector/fixtures/ip_vs_result_lbs_none.txt diff --git a/collector/fixtures/ip_vs_result_lbs_local_address_local_port.txt b/collector/fixtures/ip_vs_result_lbs_local_address_local_port.txt new file mode 100644 index 00000000..61c77c7e --- /dev/null +++ b/collector/fixtures/ip_vs_result_lbs_local_address_local_port.txt @@ -0,0 +1,33 @@ +# HELP node_ipvs_backend_connections_active The current active connections by local and remote address. +# TYPE node_ipvs_backend_connections_active gauge +node_ipvs_backend_connections_active{local_address="",local_port="0"} 385 +node_ipvs_backend_connections_active{local_address="192.168.0.22",local_port="3306"} 744 +node_ipvs_backend_connections_active{local_address="192.168.0.55",local_port="3306"} 0 +node_ipvs_backend_connections_active{local_address="192.168.0.57",local_port="3306"} 2997 +# HELP node_ipvs_backend_connections_inactive The current inactive connections by local and remote address. +# TYPE node_ipvs_backend_connections_inactive gauge +node_ipvs_backend_connections_inactive{local_address="",local_port="0"} 6 +node_ipvs_backend_connections_inactive{local_address="192.168.0.22",local_port="3306"} 5 +node_ipvs_backend_connections_inactive{local_address="192.168.0.55",local_port="3306"} 0 +node_ipvs_backend_connections_inactive{local_address="192.168.0.57",local_port="3306"} 0 +# HELP node_ipvs_backend_weight The current backend weight by local and remote address. +# TYPE node_ipvs_backend_weight gauge +node_ipvs_backend_weight{local_address="",local_port="0"} 120 +node_ipvs_backend_weight{local_address="192.168.0.22",local_port="3306"} 300 +node_ipvs_backend_weight{local_address="192.168.0.55",local_port="3306"} 100 +node_ipvs_backend_weight{local_address="192.168.0.57",local_port="3306"} 200 +# HELP node_ipvs_connections_total The total number of connections made. +# TYPE node_ipvs_connections_total counter +node_ipvs_connections_total 2.3765872e+07 +# HELP node_ipvs_incoming_bytes_total The total amount of incoming data. +# TYPE node_ipvs_incoming_bytes_total counter +node_ipvs_incoming_bytes_total 8.9991519156915e+13 +# HELP node_ipvs_incoming_packets_total The total number of incoming packets. +# TYPE node_ipvs_incoming_packets_total counter +node_ipvs_incoming_packets_total 3.811989221e+09 +# HELP node_ipvs_outgoing_bytes_total The total amount of outgoing data. +# TYPE node_ipvs_outgoing_bytes_total counter +node_ipvs_outgoing_bytes_total 0 +# HELP node_ipvs_outgoing_packets_total The total number of outgoing packets. +# TYPE node_ipvs_outgoing_packets_total counter +node_ipvs_outgoing_packets_total 0 diff --git a/collector/fixtures/ip_vs_result_lbs_local_port.txt b/collector/fixtures/ip_vs_result_lbs_local_port.txt new file mode 100644 index 00000000..ef931ffb --- /dev/null +++ b/collector/fixtures/ip_vs_result_lbs_local_port.txt @@ -0,0 +1,27 @@ +# HELP node_ipvs_backend_connections_active The current active connections by local and remote address. +# TYPE node_ipvs_backend_connections_active gauge +node_ipvs_backend_connections_active{local_port="0"} 385 +node_ipvs_backend_connections_active{local_port="3306"} 3741 +# HELP node_ipvs_backend_connections_inactive The current inactive connections by local and remote address. +# TYPE node_ipvs_backend_connections_inactive gauge +node_ipvs_backend_connections_inactive{local_port="0"} 6 +node_ipvs_backend_connections_inactive{local_port="3306"} 5 +# HELP node_ipvs_backend_weight The current backend weight by local and remote address. +# TYPE node_ipvs_backend_weight gauge +node_ipvs_backend_weight{local_port="0"} 120 +node_ipvs_backend_weight{local_port="3306"} 600 +# HELP node_ipvs_connections_total The total number of connections made. +# TYPE node_ipvs_connections_total counter +node_ipvs_connections_total 2.3765872e+07 +# HELP node_ipvs_incoming_bytes_total The total amount of incoming data. +# TYPE node_ipvs_incoming_bytes_total counter +node_ipvs_incoming_bytes_total 8.9991519156915e+13 +# HELP node_ipvs_incoming_packets_total The total number of incoming packets. +# TYPE node_ipvs_incoming_packets_total counter +node_ipvs_incoming_packets_total 3.811989221e+09 +# HELP node_ipvs_outgoing_bytes_total The total amount of outgoing data. +# TYPE node_ipvs_outgoing_bytes_total counter +node_ipvs_outgoing_bytes_total 0 +# HELP node_ipvs_outgoing_packets_total The total number of outgoing packets. +# TYPE node_ipvs_outgoing_packets_total counter +node_ipvs_outgoing_packets_total 0 diff --git a/collector/fixtures/ip_vs_result_lbs_none.txt b/collector/fixtures/ip_vs_result_lbs_none.txt new file mode 100644 index 00000000..621aa547 --- /dev/null +++ b/collector/fixtures/ip_vs_result_lbs_none.txt @@ -0,0 +1,24 @@ +# HELP node_ipvs_backend_connections_active The current active connections by local and remote address. +# TYPE node_ipvs_backend_connections_active gauge +node_ipvs_backend_connections_active 4126 +# HELP node_ipvs_backend_connections_inactive The current inactive connections by local and remote address. +# TYPE node_ipvs_backend_connections_inactive gauge +node_ipvs_backend_connections_inactive 11 +# HELP node_ipvs_backend_weight The current backend weight by local and remote address. +# TYPE node_ipvs_backend_weight gauge +node_ipvs_backend_weight 720 +# HELP node_ipvs_connections_total The total number of connections made. +# TYPE node_ipvs_connections_total counter +node_ipvs_connections_total 2.3765872e+07 +# HELP node_ipvs_incoming_bytes_total The total amount of incoming data. +# TYPE node_ipvs_incoming_bytes_total counter +node_ipvs_incoming_bytes_total 8.9991519156915e+13 +# HELP node_ipvs_incoming_packets_total The total number of incoming packets. +# TYPE node_ipvs_incoming_packets_total counter +node_ipvs_incoming_packets_total 3.811989221e+09 +# HELP node_ipvs_outgoing_bytes_total The total amount of outgoing data. +# TYPE node_ipvs_outgoing_bytes_total counter +node_ipvs_outgoing_bytes_total 0 +# HELP node_ipvs_outgoing_packets_total The total number of outgoing packets. +# TYPE node_ipvs_outgoing_packets_total counter +node_ipvs_outgoing_packets_total 0 diff --git a/collector/ipvs_linux.go b/collector/ipvs_linux.go index 11adf0fa..b5c8d73e 100644 --- a/collector/ipvs_linux.go +++ b/collector/ipvs_linux.go @@ -18,22 +18,53 @@ package collector import ( "fmt" "os" + "sort" "strconv" + "strings" "github.com/go-kit/kit/log" "github.com/go-kit/kit/log/level" "github.com/prometheus/client_golang/prometheus" "github.com/prometheus/procfs" + kingpin "gopkg.in/alecthomas/kingpin.v2" ) type ipvsCollector struct { Collector fs procfs.FS + backendLabels []string backendConnectionsActive, backendConnectionsInact, backendWeight typedDesc connections, incomingPackets, outgoingPackets, incomingBytes, outgoingBytes typedDesc logger log.Logger } +type ipvsBackendStatus struct { + ActiveConn uint64 + InactConn uint64 + Weight uint64 +} + +const ( + ipvsLabelLocalAddress = "local_address" + ipvsLabelLocalPort = "local_port" + ipvsLabelRemoteAddress = "remote_address" + ipvsLabelRemotePort = "remote_port" + ipvsLabelProto = "proto" + ipvsLabelLocalMark = "local_mark" +) + +var ( + fullIpvsBackendLabels = []string{ + ipvsLabelLocalAddress, + ipvsLabelLocalPort, + ipvsLabelRemoteAddress, + ipvsLabelRemotePort, + ipvsLabelProto, + ipvsLabelLocalMark, + } + ipvsLabels = kingpin.Flag("collector.ipvs.backend-labels", "Comma separated list for IPVS backend stats labels.").Default(strings.Join(fullIpvsBackendLabels, ",")).String() +) + func init() { registerCollector("ipvs", defaultEnabled, NewIPVSCollector) } @@ -46,19 +77,15 @@ func NewIPVSCollector(logger log.Logger) (Collector, error) { func newIPVSCollector(logger log.Logger) (*ipvsCollector, error) { var ( - ipvsBackendLabelNames = []string{ - "local_address", - "local_port", - "remote_address", - "remote_port", - "proto", - "local_mark", - } c ipvsCollector err error subsystem = "ipvs" ) + if c.backendLabels, err = c.parseIpvsLabels(*ipvsLabels); err != nil { + return nil, err + } + c.logger = logger c.fs, err = procfs.NewFS(*procPath) if err != nil { @@ -93,17 +120,17 @@ func newIPVSCollector(logger log.Logger) (*ipvsCollector, error) { c.backendConnectionsActive = typedDesc{prometheus.NewDesc( prometheus.BuildFQName(namespace, subsystem, "backend_connections_active"), "The current active connections by local and remote address.", - ipvsBackendLabelNames, nil, + c.backendLabels, nil, ), prometheus.GaugeValue} c.backendConnectionsInact = typedDesc{prometheus.NewDesc( prometheus.BuildFQName(namespace, subsystem, "backend_connections_inactive"), "The current inactive connections by local and remote address.", - ipvsBackendLabelNames, nil, + c.backendLabels, nil, ), prometheus.GaugeValue} c.backendWeight = typedDesc{prometheus.NewDesc( prometheus.BuildFQName(namespace, subsystem, "backend_weight"), "The current backend weight by local and remote address.", - ipvsBackendLabelNames, nil, + c.backendLabels, nil, ), prometheus.GaugeValue} return &c, nil @@ -130,22 +157,74 @@ func (c *ipvsCollector) Update(ch chan<- prometheus.Metric) error { return fmt.Errorf("could not get backend status: %s", err) } + sums := map[string]ipvsBackendStatus{} + labelValues := map[string][]string{} for _, backend := range backendStats { localAddress := "" if backend.LocalAddress.String() != "" { localAddress = backend.LocalAddress.String() } - labelValues := []string{ - localAddress, - strconv.FormatUint(uint64(backend.LocalPort), 10), - backend.RemoteAddress.String(), - strconv.FormatUint(uint64(backend.RemotePort), 10), - backend.Proto, - backend.LocalMark, + kv := make([]string, len(c.backendLabels)) + for i, label := range c.backendLabels { + var labelValue string + switch label { + case ipvsLabelLocalAddress: + labelValue = localAddress + case ipvsLabelLocalPort: + labelValue = strconv.FormatUint(uint64(backend.LocalPort), 10) + case ipvsLabelRemoteAddress: + labelValue = backend.RemoteAddress.String() + case ipvsLabelRemotePort: + labelValue = strconv.FormatUint(uint64(backend.RemotePort), 10) + case ipvsLabelProto: + labelValue = backend.Proto + case ipvsLabelLocalMark: + labelValue = backend.LocalMark + } + kv[i] = labelValue } - ch <- c.backendConnectionsActive.mustNewConstMetric(float64(backend.ActiveConn), labelValues...) - ch <- c.backendConnectionsInact.mustNewConstMetric(float64(backend.InactConn), labelValues...) - ch <- c.backendWeight.mustNewConstMetric(float64(backend.Weight), labelValues...) + key := strings.Join(kv, "-") + status := sums[key] + status.ActiveConn += backend.ActiveConn + status.InactConn += backend.InactConn + status.Weight += backend.Weight + sums[key] = status + labelValues[key] = kv + } + for key, status := range sums { + kv := labelValues[key] + ch <- c.backendConnectionsActive.mustNewConstMetric(float64(status.ActiveConn), kv...) + ch <- c.backendConnectionsInact.mustNewConstMetric(float64(status.InactConn), kv...) + ch <- c.backendWeight.mustNewConstMetric(float64(status.Weight), kv...) } return nil } + +func (c *ipvsCollector) parseIpvsLabels(labelString string) ([]string, error) { + labels := strings.Split(labelString, ",") + labelSet := make(map[string]bool, len(labels)) + results := make([]string, 0, len(labels)) + for _, label := range labels { + if label != "" { + labelSet[label] = true + } + } + + for _, label := range fullIpvsBackendLabels { + if labelSet[label] { + results = append(results, label) + } + delete(labelSet, label) + } + + if len(labelSet) > 0 { + keys := make([]string, 0, len(labelSet)) + for label := range labelSet { + keys = append(keys, label) + } + sort.Strings(keys) + return nil, fmt.Errorf("unknown IPVS backend labels: %q", strings.Join(keys, ", ")) + } + + return results, nil +} diff --git a/collector/ipvs_linux_test.go b/collector/ipvs_linux_test.go index a1c0cba8..43c68395 100644 --- a/collector/ipvs_linux_test.go +++ b/collector/ipvs_linux_test.go @@ -14,47 +14,131 @@ package collector import ( + "errors" "fmt" - "github.com/go-kit/kit/log" "io/ioutil" "net/http" "net/http/httptest" "strings" "testing" + "github.com/go-kit/kit/log" + "github.com/prometheus/client_golang/prometheus" "github.com/prometheus/client_golang/prometheus/promhttp" "gopkg.in/alecthomas/kingpin.v2" ) func TestIPVSCollector(t *testing.T) { - if _, err := kingpin.CommandLine.Parse([]string{"--path.procfs", "fixtures/proc"}); err != nil { - t.Fatal(err) + testcases := []struct { + labels string + expects []string + err error + }{ + { + "", + []string{ + prometheus.NewDesc("node_ipvs_connections_total", "The total number of connections made.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_incoming_packets_total", "The total number of incoming packets.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_outgoing_packets_total", "The total number of outgoing packets.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_incoming_bytes_total", "The total amount of incoming data.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_outgoing_bytes_total", "The total amount of outgoing data.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_backend_connections_active", "The current active connections by local and remote address.", []string{"local_address", "local_port", "remote_address", "remote_port", "proto", "local_mark"}, nil).String(), + prometheus.NewDesc("node_ipvs_backend_connections_inactive", "The current inactive connections by local and remote address.", []string{"local_address", "local_port", "remote_address", "remote_port", "proto", "local_mark"}, nil).String(), + prometheus.NewDesc("node_ipvs_backend_weight", "The current backend weight by local and remote address.", []string{"local_address", "local_port", "remote_address", "remote_port", "proto", "local_mark"}, nil).String(), + }, + nil, + }, + { + "", + []string{ + prometheus.NewDesc("node_ipvs_connections_total", "The total number of connections made.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_incoming_packets_total", "The total number of incoming packets.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_outgoing_packets_total", "The total number of outgoing packets.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_incoming_bytes_total", "The total amount of incoming data.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_outgoing_bytes_total", "The total amount of outgoing data.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_backend_connections_active", "The current active connections by local and remote address.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_backend_connections_inactive", "The current inactive connections by local and remote address.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_backend_weight", "The current backend weight by local and remote address.", nil, nil).String(), + }, + nil, + }, + { + "local_port", + []string{ + prometheus.NewDesc("node_ipvs_connections_total", "The total number of connections made.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_incoming_packets_total", "The total number of incoming packets.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_outgoing_packets_total", "The total number of outgoing packets.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_incoming_bytes_total", "The total amount of incoming data.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_outgoing_bytes_total", "The total amount of outgoing data.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_backend_connections_active", "The current active connections by local and remote address.", []string{"local_port"}, nil).String(), + prometheus.NewDesc("node_ipvs_backend_connections_inactive", "The current inactive connections by local and remote address.", []string{"local_port"}, nil).String(), + prometheus.NewDesc("node_ipvs_backend_weight", "The current backend weight by local and remote address.", []string{"local_port"}, nil).String(), + }, + nil, + }, + { + "local_address,local_port", + []string{ + prometheus.NewDesc("node_ipvs_connections_total", "The total number of connections made.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_incoming_packets_total", "The total number of incoming packets.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_outgoing_packets_total", "The total number of outgoing packets.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_incoming_bytes_total", "The total amount of incoming data.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_outgoing_bytes_total", "The total amount of outgoing data.", nil, nil).String(), + prometheus.NewDesc("node_ipvs_backend_connections_active", "The current active connections by local and remote address.", []string{"local_address", "local_port"}, nil).String(), + prometheus.NewDesc("node_ipvs_backend_connections_inactive", "The current inactive connections by local and remote address.", []string{"local_address", "local_port"}, nil).String(), + prometheus.NewDesc("node_ipvs_backend_weight", "The current backend weight by local and remote address.", []string{"local_address", "local_port"}, nil).String(), + }, + nil, + }, + { + "invalid_label", + nil, + errors.New(`unknown IPVS backend labels: "invalid_label"`), + }, + { + "invalid_label,bad_label", + nil, + errors.New(`unknown IPVS backend labels: "bad_label, invalid_label"`), + }, } - collector, err := newIPVSCollector(log.NewNopLogger()) - if err != nil { - t.Fatal(err) - } - sink := make(chan prometheus.Metric) - go func() { - err = collector.Update(sink) - if err != nil { - panic(fmt.Sprintf("failed to update collector: %v", err)) - } - }() - for expected, got := range map[string]string{ - prometheus.NewDesc("node_ipvs_connections_total", "The total number of connections made.", nil, nil).String(): (<-sink).Desc().String(), - prometheus.NewDesc("node_ipvs_incoming_packets_total", "The total number of incoming packets.", nil, nil).String(): (<-sink).Desc().String(), - prometheus.NewDesc("node_ipvs_outgoing_packets_total", "The total number of outgoing packets.", nil, nil).String(): (<-sink).Desc().String(), - prometheus.NewDesc("node_ipvs_incoming_bytes_total", "The total amount of incoming data.", nil, nil).String(): (<-sink).Desc().String(), - prometheus.NewDesc("node_ipvs_outgoing_bytes_total", "The total amount of outgoing data.", nil, nil).String(): (<-sink).Desc().String(), - prometheus.NewDesc("node_ipvs_backend_connections_active", "The current active connections by local and remote address.", []string{"local_address", "local_port", "remote_address", "remote_port", "proto", "local_mark"}, nil).String(): (<-sink).Desc().String(), - prometheus.NewDesc("node_ipvs_backend_connections_inactive", "The current inactive connections by local and remote address.", []string{"local_address", "local_port", "remote_address", "remote_port", "proto", "local_mark"}, nil).String(): (<-sink).Desc().String(), - prometheus.NewDesc("node_ipvs_backend_weight", "The current backend weight by local and remote address.", []string{"local_address", "local_port", "remote_address", "remote_port", "proto", "local_mark"}, nil).String(): (<-sink).Desc().String(), - } { - if expected != got { - t.Fatalf("Expected '%s' but got '%s'", expected, got) - } + for _, test := range testcases { + t.Run(test.labels, func(t *testing.T) { + args := []string{"--path.procfs", "fixtures/proc"} + if test.labels != "" { + args = append(args, "--collector.ipvs.backend-labels="+test.labels) + } + if _, err := kingpin.CommandLine.Parse(args); err != nil { + t.Fatal(err) + } + collector, err := newIPVSCollector(log.NewNopLogger()) + if err != nil { + if test.err == nil { + t.Fatal(err) + } + if !strings.Contains(err.Error(), test.err.Error()) { + t.Fatalf("expect error: %v contains %v", err, test.err) + } + return + } + if test.err != nil { + t.Fatalf("expect error: %v but got no error", test.err) + } + + sink := make(chan prometheus.Metric) + go func() { + err = collector.Update(sink) + if err != nil { + panic(fmt.Sprintf("failed to update collector: %v", err)) + } + }() + for _, expected := range test.expects { + got := (<-sink).Desc().String() + if expected != got { + t.Fatalf("Expected '%s' but got '%s'", expected, got) + } + } + }) } } @@ -77,44 +161,61 @@ func (c miniCollector) Describe(ch chan<- *prometheus.Desc) { } func TestIPVSCollectorResponse(t *testing.T) { - if _, err := kingpin.CommandLine.Parse([]string{"--path.procfs", "fixtures/proc"}); err != nil { - t.Fatal(err) + testcases := []struct { + labels string + metricsFile string + }{ + {"", "fixtures/ip_vs_result.txt"}, + {"", "fixtures/ip_vs_result_lbs_none.txt"}, + {"local_port", "fixtures/ip_vs_result_lbs_local_port.txt"}, + {"local_address,local_port", "fixtures/ip_vs_result_lbs_local_address_local_port.txt"}, } - collector, err := NewIPVSCollector(log.NewNopLogger()) - if err != nil { - t.Fatal(err) - } - prometheus.MustRegister(miniCollector{c: collector}) - - rw := httptest.NewRecorder() - promhttp.Handler().ServeHTTP(rw, &http.Request{}) - - metricsFile := "fixtures/ip_vs_result.txt" - wantMetrics, err := ioutil.ReadFile(metricsFile) - if err != nil { - t.Fatalf("unable to read input test file %s: %s", metricsFile, err) - } - - wantLines := strings.Split(string(wantMetrics), "\n") - gotLines := strings.Split(string(rw.Body.String()), "\n") - gotLinesIdx := 0 - - // Until the Prometheus Go client library offers better testability - // (https://github.com/prometheus/client_golang/issues/58), we simply compare - // verbatim text-format metrics outputs, but ignore any lines we don't have - // in the fixture. Put differently, we are only testing that each line from - // the fixture is present, in the order given. -wantLoop: - for _, want := range wantLines { - for _, got := range gotLines[gotLinesIdx:] { - if want == got { - // this is a line we are interested in, and it is correct - continue wantLoop - } else { - gotLinesIdx++ + for _, test := range testcases { + t.Run(test.labels, func(t *testing.T) { + args := []string{"--path.procfs", "fixtures/proc"} + if test.labels != "" { + args = append(args, "--collector.ipvs.backend-labels="+test.labels) } - } - // if this point is reached, the line we want was missing - t.Fatalf("Missing expected output line(s), first missing line is %s", want) + if _, err := kingpin.CommandLine.Parse(args); err != nil { + t.Fatal(err) + } + collector, err := NewIPVSCollector(log.NewNopLogger()) + if err != nil { + t.Fatal(err) + } + registry := prometheus.NewRegistry() + registry.MustRegister(miniCollector{c: collector}) + + rw := httptest.NewRecorder() + promhttp.InstrumentMetricHandler(registry, promhttp.HandlerFor(registry, promhttp.HandlerOpts{})).ServeHTTP(rw, &http.Request{}) + + wantMetrics, err := ioutil.ReadFile(test.metricsFile) + if err != nil { + t.Fatalf("unable to read input test file %s: %s", test.metricsFile, err) + } + + wantLines := strings.Split(string(wantMetrics), "\n") + gotLines := strings.Split(string(rw.Body.String()), "\n") + gotLinesIdx := 0 + + // Until the Prometheus Go client library offers better testability + // (https://github.com/prometheus/client_golang/issues/58), we simply compare + // verbatim text-format metrics outputs, but ignore any lines we don't have + // in the fixture. Put differently, we are only testing that each line from + // the fixture is present, in the order given. + wantLoop: + for _, want := range wantLines { + for _, got := range gotLines[gotLinesIdx:] { + if want == got { + // this is a line we are interested in, and it is correct + continue wantLoop + } else { + gotLinesIdx++ + } + } + // if this point is reached, the line we want was missing + t.Fatalf("Missing expected output line(s), first missing line is %s", want) + } + }) } }