Add pingdom_min_request_limit internal metric

README.md

@@ -61,17 +61,18 @@ on how to build your own image and push it to your private registry.
 
 ## Exported Metrics
 
-| Metric Name                                         | Description                                                                     |
-| --------------------------------------------------- | ------------------------------------------------------------------------------- |
-| `pingdom_up`                                        | Was the last query on Pingdom API successful                                    |
-| `pingdom_uptime_status`                             | The current status of the check (1: up, 0: down)                                |
-| `pingdom_uptime_response_time_seconds`              | The response time of last test, in seconds                                      |
-| `pingdom_slo_period_seconds`                        | Outage check period, in seconds (see `-outage-check-period` flag)               |
-| `pingdom_outages_total`                             | Number of outages within the outage check period                                |
-| `pingdom_down_seconds`                              | Total down time within the outage check period, in seconds                      |
-| `pingdom_up_seconds`                                | Total up time within the outage check period, in seconds                        |
-| `pingdom_uptime_slo_error_budget_total_seconds`     | Maximum number of allowed downtime, in seconds, according to the uptime SLO     |
-| `pingdom_uptime_slo_error_budget_available_seconds` | Number of seconds of downtime we can still have without breaking the uptime SLO |
+| Metric Name                                         | Description                                                                                                      |
+| --------------------------------------------------- |------------------------------------------------------------------------------------------------------------------|
+| `pingdom_up`                                        | Was the last query on Pingdom API successful                                                                     |
+| `pingdom_uptime_response_time_seconds`              | The minimum remaining requests allowed before hitting the short-term or long-term rate limit in the Pingdom API. |
+| `pingdom_uptime_status`                             | The current status of the check (1: up, 0: down)                                                                 |
+| `pingdom_uptime_response_time_seconds`              | The response time of last test, in seconds                                                                       |
+| `pingdom_slo_period_seconds`                        | Outage check period, in seconds (see `-outage-check-period` flag)                                                |
+| `pingdom_outages_total`                             | Number of outages within the outage check period                                                                 |
+| `pingdom_down_seconds`                              | Total down time within the outage check period, in seconds                                                       |
+| `pingdom_up_seconds`                                | Total up time within the outage check period, in seconds                                                         |
+| `pingdom_uptime_slo_error_budget_total_seconds`     | Maximum number of allowed downtime, in seconds, according to the uptime SLO                                      |
+| `pingdom_uptime_slo_error_budget_available_seconds` | Number of seconds of downtime we can still have without breaking the uptime SLO                                  |
 
 ## Development
 

cmd/pingdom-exporter/main.go

@@ -33,6 +33,12 @@ var (
 		nil, nil,
 	)
 
+	pingdomMinRequestLimitDesc = prometheus.NewDesc(
+		"pingdom_rate_limit_min_remaining_requests",
+		"Tracks the minimum remaining requests allowed before hitting the short-term or long-term rate limit in the Pingdom API.",
+		nil, nil,
+	)
+
 	pingdomOutageCheckPeriodDesc = prometheus.NewDesc(
 		"pingdom_slo_period_seconds",
 		"Outage check period, in seconds",
@@ -96,6 +102,7 @@ type pingdomCollector struct {
 
 func (pc pingdomCollector) Describe(ch chan<- *prometheus.Desc) {
 	ch <- pingdomUpDesc
+	ch <- pingdomMinRequestLimitDesc
 	ch <- pingdomOutageCheckPeriodDesc
 	ch <- pingdomCheckStatusDesc
 	ch <- pingdomCheckResponseTimeDesc
@@ -110,11 +117,17 @@ func (pc pingdomCollector) Collect(ch chan<- prometheus.Metric) {
 	outageCheckPeriodDuration := time.Hour * time.Duration(24*outageCheckPeriod)
 	outageCheckPeriodSecs := float64(outageCheckPeriodDuration / time.Second)
 
-	checks, err := pc.client.Checks.List(map[string]string{
+	checks, minReqLimit, err := pc.client.Checks.List(map[string]string{
 		"include_tags": "true",
 		"tags":         pc.client.Tags,
 	})
 
+	ch <- prometheus.MustNewConstMetric(
+		pingdomMinRequestLimitDesc,
+		prometheus.GaugeValue,
+		minReqLimit,
+	)
+
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "Error getting checks: %v", err)
 		ch <- prometheus.MustNewConstMetric(

pkg/pingdom/check.go

@@ -3,6 +3,18 @@ package pingdom
 import (
 	"encoding/json"
 	"io/ioutil"
+	"math"
+	"net/http"
+	"regexp"
+	"strconv"
+)
+
+var (
+	reqLimitHeaderKeys = []string{
+		"req-limit-short",
+		"req-limit-long",
+	}
+	reqLimitRe = regexp.MustCompile(`Remaining: (\d+) Time until reset: (\d+)`)
 )
 
 // CheckService provides an interface to Pingdom checks.
@@ -13,30 +25,48 @@ type CheckService struct {
 // List returns a list of checks from Pingdom.
 // This returns type CheckResponse rather than Check since the
 // Pingdom API does not return a complete representation of a check.
-func (cs *CheckService) List(params ...map[string]string) ([]CheckResponse, error) {
+func (cs *CheckService) List(params ...map[string]string) ([]CheckResponse, float64, error) {
 	param := map[string]string{}
 	if len(params) == 1 {
 		param = params[0]
 	}
 	req, err := cs.client.NewRequest("GET", "/checks", param)
 	if err != nil {
-		return nil, err
+		return nil, 0, err
 	}
 
 	resp, err := cs.client.client.Do(req)
 	if err != nil {
-		return nil, err
+		return nil, 0, err
 	}
 	defer resp.Body.Close()
 
+	minRequestLimit := minRequestLimitFromHeader(resp.Header)
+
 	if err := validateResponse(resp); err != nil {
-		return nil, err
+		return nil, minRequestLimit, err
 	}
 
 	bodyBytes, _ := ioutil.ReadAll(resp.Body)
 	bodyString := string(bodyBytes)
 	m := &listChecksJSONResponse{}
 	err = json.Unmarshal([]byte(bodyString), &m)
 
-	return m.Checks, err
+	return m.Checks, minRequestLimit, err
+}
+
+func minRequestLimitFromHeader(header http.Header) float64 {
+	minRequestLimit := math.MaxFloat64
+
+	for _, key := range reqLimitHeaderKeys {
+		matches := reqLimitRe.FindStringSubmatch(header.Get(key))
+		if len(matches) > 0 {
+			limit, err := strconv.ParseFloat(matches[1], 64)
+			if err == nil && limit < minRequestLimit {
+				minRequestLimit = limit
+			}
+		}
+	}
+
+	return minRequestLimit
 }

pkg/pingdom/check_test.go

@@ -2,6 +2,7 @@ package pingdom
 
 import (
 	"fmt"
+	"math"
 	"net/http"
 	"testing"
 
@@ -14,6 +15,7 @@ func TestCheckServiceList(t *testing.T) {
 
 	mux.HandleFunc("/checks", func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
+		w.Header().Set("req-limit-long", "Remaining: 12 Time until reset: 34")
 		fmt.Fprint(w, `{
 			"checks": [
 				{
@@ -141,7 +143,52 @@ func TestCheckServiceList(t *testing.T) {
 		},
 	}
 
-	checks, err := client.Checks.List()
+	checks, minRequestLimit, err := client.Checks.List()
 	assert.NoError(t, err)
 	assert.Equal(t, want, checks)
+	assert.EqualValues(t, 12, minRequestLimit)
+}
+
+func TestMinRequestLimitFromResp(t *testing.T) {
+	tc := []struct {
+		header   http.Header
+		expected float64
+	}{
+		{
+			header:   http.Header{},
+			expected: math.MaxFloat64,
+		},
+		{
+			header: http.Header{
+				"Req-Limit-Short": []string{"Remaining: 12 Time until reset: 34"},
+			},
+			expected: 12,
+		},
+		{
+			header: http.Header{
+				"Req-Limit-Long": []string{"Remaining: 56 Time until reset: 78"},
+			},
+			expected: 56,
+		},
+		{
+			header: http.Header{
+				"Req-Limit-Long":  []string{"Remaining: 0 Time until reset: 78"},
+				"Req-Limit-Short": []string{"Remaining: 12 Time until reset: 34"},
+			},
+			expected: 0,
+		},
+		{
+			header: http.Header{
+				"Req-Limit-Long": []string{"invalid"},
+			},
+			expected: math.MaxFloat64,
+		},
+	}
+
+	for _, tt := range tc {
+		t.Run(fmt.Sprintf("%v", tt.header), func(t *testing.T) {
+			actual := minRequestLimitFromHeader(tt.header)
+			assert.Equal(t, tt.expected, actual)
+		})
+	}
 }