Include Go plugin sources in main repository. (#16997)

* Include Go plugin sources in main repository.

* Fix CI issues.

* Rename source tree.

10 files changed, 1567 insertions, 0 deletions

diff --git a/src/go/collectors/go.d.plugin/modules/haproxy/README.md b/src/go/collectors/go.d.plugin/modules/haproxy/README.md
new file mode 120000
index 0000000000..2f52cf8463
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/modules/haproxy/README.md
@@ -0,0 +1 @@
+integrations/haproxy.md
\ No newline at end of file
diff --git a/src/go/collectors/go.d.plugin/modules/haproxy/charts.go b/src/go/collectors/go.d.plugin/modules/haproxy/charts.go
new file mode 100644
index 0000000000..8c5f6bef64
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/modules/haproxy/charts.go
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package haproxy
+
+import (
+	"fmt"
+
+	"github.com/netdata/go.d.plugin/agent/module"
+)
+
+var charts = module.Charts{
+	chartBackendCurrentSessions.Copy(),
+	chartBackendSessions.Copy(),
+
+	chartBackendResponseTimeAverage.Copy(),
+
+	chartBackendQueueTimeAverage.Copy(),
+	chartBackendCurrentQueue.Copy(),
+}
+
+var (
+	chartBackendCurrentSessions = module.Chart{
+		ID:    "backend_current_sessions",
+		Title: "Current number of active sessions",
+		Units: "sessions",
+		Fam:   "backend sessions",
+		Ctx:   "haproxy.backend_current_sessions",
+	}
+	chartBackendSessions = module.Chart{
+		ID:    "backend_sessions",
+		Title: "Sessions rate",
+		Units: "sessions/s",
+		Fam:   "backend sessions",
+		Ctx:   "haproxy.backend_sessions",
+	}
+)
+
+var (
+	chartBackendResponseTimeAverage = module.Chart{
+		ID:    "backend_response_time_average",
+		Title: "Average response time for last 1024 successful connections",
+		Units: "milliseconds",
+		Fam:   "backend responses",
+		Ctx:   "haproxy.backend_response_time_average",
+	}
+	chartTemplateBackendHTTPResponses = module.Chart{
+		ID:    "backend_http_responses_proxy_%s",
+		Title: "HTTP responses by code class for <code>%s</code> proxy",
+		Units: "responses/s",
+		Fam:   "backend responses",
+		Ctx:   "haproxy.backend_http_responses",
+		Type:  module.Stacked,
+		Dims: module.Dims{
+			{ID: "haproxy_backend_http_responses_1xx_proxy_%s", Name: "1xx", Algo: module.Incremental},
+			{ID: "haproxy_backend_http_responses_2xx_proxy_%s", Name: "2xx", Algo: module.Incremental},
+			{ID: "haproxy_backend_http_responses_3xx_proxy_%s", Name: "3xx", Algo: module.Incremental},
+			{ID: "haproxy_backend_http_responses_4xx_proxy_%s", Name: "4xx", Algo: module.Incremental},
+			{ID: "haproxy_backend_http_responses_5xx_proxy_%s", Name: "5xx", Algo: module.Incremental},
+			{ID: "haproxy_backend_http_responses_other_proxy_%s", Name: "other", Algo: module.Incremental},
+		},
+	}
+)
+
+var (
+	chartBackendQueueTimeAverage = module.Chart{
+		ID:    "backend_queue_time_average",
+		Title: "Average queue time for last 1024 successful connections",
+		Units: "milliseconds",
+		Fam:   "backend queue",
+		Ctx:   "haproxy.backend_queue_time_average",
+	}
+	chartBackendCurrentQueue = module.Chart{
+		ID:    "backend_current_queue",
+		Title: "Current number of queued requests",
+		Units: "requests",
+		Fam:   "backend queue",
+		Ctx:   "haproxy.backend_current_queue",
+	}
+)
+
+var (
+	chartTemplateBackendNetworkIO = module.Chart{
+		ID:    "backend_network_io_proxy_%s",
+		Title: "Network traffic for <code>%s</code> proxy",
+		Units: "bytes/s",
+		Fam:   "backend network",
+		Ctx:   "haproxy.backend_network_io",
+		Type:  module.Area,
+		Dims: module.Dims{
+			{ID: "haproxy_backend_bytes_in_proxy_%s", Name: "in", Algo: module.Incremental},
+			{ID: "haproxy_backend_bytes_out_proxy_%s", Name: "out", Algo: module.Incremental, Mul: -1},
+		},
+	}
+)
+
+func newChartBackendHTTPResponses(proxy string) *module.Chart {
+	return newBackendChartFromTemplate(chartTemplateBackendHTTPResponses, proxy)
+}
+
+func newChartBackendNetworkIO(proxy string) *module.Chart {
+	return newBackendChartFromTemplate(chartTemplateBackendNetworkIO, proxy)
+}
+
+func newBackendChartFromTemplate(tpl module.Chart, proxy string) *module.Chart {
+	c := tpl.Copy()
+	c.ID = fmt.Sprintf(c.ID, proxy)
+	c.Title = fmt.Sprintf(c.Title, proxy)
+	for _, d := range c.Dims {
+		d.ID = fmt.Sprintf(d.ID, proxy)
+	}
+	return c
+}
diff --git a/src/go/collectors/go.d.plugin/modules/haproxy/collect.go b/src/go/collectors/go.d.plugin/modules/haproxy/collect.go
new file mode 100644
index 0000000000..10d24a088b
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/modules/haproxy/collect.go
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package haproxy
+
+import (
+	"errors"
+	"strings"
+
+	"github.com/netdata/go.d.plugin/agent/module"
+	"github.com/netdata/go.d.plugin/pkg/prometheus"
+)
+
+const (
+	metricBackendSessionsTotal              = "haproxy_backend_sessions_total"
+	metricBackendCurrentSessions            = "haproxy_backend_current_sessions"
+	metricBackendHTTPResponsesTotal         = "haproxy_backend_http_responses_total"
+	metricBackendResponseTimeAverageSeconds = "haproxy_backend_response_time_average_seconds"
+	metricBackendCurrentQueue               = "haproxy_backend_current_queue"
+	metricBackendQueueTimeAverageSeconds    = "haproxy_backend_queue_time_average_seconds"
+	metricBackendBytesInTotal               = "haproxy_backend_bytes_in_total"
+	metricBackendBytesOutTotal              = "haproxy_backend_bytes_out_total"
+)
+
+func isHaproxyMetrics(pms prometheus.Series) bool {
+	for _, pm := range pms {
+		if strings.HasPrefix(pm.Name(), "haproxy_") {
+			return true
+		}
+	}
+	return false
+}
+
+func (h *Haproxy) collect() (map[string]int64, error) {
+	pms, err := h.prom.ScrapeSeries()
+	if err != nil {
+		return nil, err
+	}
+
+	if h.validateMetrics && !isHaproxyMetrics(pms) {
+		return nil, errors.New("unexpected metrics (not HAProxy)")
+	}
+	h.validateMetrics = false
+
+	mx := make(map[string]int64)
+	for _, pm := range pms {
+		proxy := pm.Labels.Get("proxy")
+		if proxy == "" {
+			continue
+		}
+
+		if !h.proxies[proxy] {
+			h.proxies[proxy] = true
+			h.addProxyToCharts(proxy)
+		}
+
+		mx[dimID(pm)] = int64(pm.Value * multiplier(pm))
+	}
+
+	return mx, nil
+}
+
+func (h *Haproxy) addProxyToCharts(proxy string) {
+	h.addDimToChart(chartBackendCurrentSessions.ID, &module.Dim{
+		ID:   proxyDimID(metricBackendCurrentSessions, proxy),
+		Name: proxy,
+	})
+	h.addDimToChart(chartBackendSessions.ID, &module.Dim{
+		ID:   proxyDimID(metricBackendSessionsTotal, proxy),
+		Name: proxy,
+		Algo: module.Incremental,
+	})
+
+	h.addDimToChart(chartBackendResponseTimeAverage.ID, &module.Dim{
+		ID:   proxyDimID(metricBackendResponseTimeAverageSeconds, proxy),
+		Name: proxy,
+	})
+	if err := h.Charts().Add(newChartBackendHTTPResponses(proxy)); err != nil {
+		h.Warning(err)
+	}
+
+	h.addDimToChart(chartBackendCurrentQueue.ID, &module.Dim{
+		ID:   proxyDimID(metricBackendCurrentQueue, proxy),
+		Name: proxy,
+	})
+	h.addDimToChart(chartBackendQueueTimeAverage.ID, &module.Dim{
+		ID:   proxyDimID(metricBackendQueueTimeAverageSeconds, proxy),
+		Name: proxy,
+	})
+
+	if err := h.Charts().Add(newChartBackendNetworkIO(proxy)); err != nil {
+		h.Warning(err)
+	}
+}
+
+func (h *Haproxy) addDimToChart(chartID string, dim *module.Dim) {
+	chart := h.Charts().Get(chartID)
+	if chart == nil {
+		h.Warningf("error on adding '%s' dimension: can not find '%s' chart", dim.ID, chartID)
+		return
+	}
+	if err := chart.AddDim(dim); err != nil {
+		h.Warning(err)
+		return
+	}
+	chart.MarkNotCreated()
+}
+
+func multiplier(pm prometheus.SeriesSample) float64 {
+	switch pm.Name() {
+	case metricBackendResponseTimeAverageSeconds,
+		metricBackendQueueTimeAverageSeconds:
+		// to milliseconds
+		return 1000
+	}
+	return 1
+}
+
+func dimID(pm prometheus.SeriesSample) string {
+	proxy := pm.Labels.Get("proxy")
+	if proxy == "" {
+		return ""
+	}
+
+	name := cleanMetricName(pm.Name())
+	if pm.Name() == metricBackendHTTPResponsesTotal {
+		name += "_" + pm.Labels.Get("code")
+	}
+	return proxyDimID(name, proxy)
+}
+
+func proxyDimID(metric, proxy string) string {
+	return cleanMetricName(metric) + "_proxy_" + proxy
+}
+
+func cleanMetricName(name string) string {
+	if strings.HasSuffix(name, "_total") {
+		return name[:len(name)-6]
+	}
+	if strings.HasSuffix(name, "_seconds") {
+		return name[:len(name)-8]
+	}
+	return name
+}
diff --git a/src/go/collectors/go.d.plugin/modules/haproxy/config_schema.json b/src/go/collectors/go.d.plugin/modules/haproxy/config_schema.json
new file mode 100644
index 0000000000..9fa8cd1114
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/modules/haproxy/config_schema.json
@@ -0,0 +1,59 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "title": "go.d/haproxy job configuration schema.",
+  "type": "object",
+  "properties": {
+    "name": {
+      "type": "string"
+    },
+    "url": {
+      "type": "string"
+    },
+    "timeout": {
+      "type": [
+        "string",
+        "integer"
+      ]
+    },
+    "username": {
+      "type": "string"
+    },
+    "password": {
+      "type": "string"
+    },
+    "proxy_url": {
+      "type": "string"
+    },
+    "proxy_username": {
+      "type": "string"
+    },
+    "proxy_password": {
+      "type": "string"
+    },
+    "headers": {
+      "type": "object",
+      "additionalProperties": {
+        "type": "string"
+      }
+    },
+    "not_follow_redirects": {
+      "type": "boolean"
+    },
+    "tls_ca": {
+      "type": "string"
+    },
+    "tls_cert": {
+      "type": "string"
+    },
+    "tls_key": {
+      "type": "string"
+    },
+    "insecure_skip_verify": {
+      "type": "boolean"
+    }
+  },
+  "required": [
+    "name",
+    "url"
+  ]
+}
diff --git a/src/go/collectors/go.d.plugin/modules/haproxy/haproxy.go b/src/go/collectors/go.d.plugin/modules/haproxy/haproxy.go
new file mode 100644
index 0000000000..ffc936711d
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/modules/haproxy/haproxy.go
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package haproxy
+
+import (
+	_ "embed"
+	"time"
+
+	"github.com/netdata/go.d.plugin/agent/module"
+	"github.com/netdata/go.d.plugin/pkg/prometheus"
+	"github.com/netdata/go.d.plugin/pkg/web"
+)
+
+//go:embed "config_schema.json"
+var configSchema string
+
+func init() {
+	module.Register("haproxy", module.Creator{
+		JobConfigSchema: configSchema,
+		Create:          func() module.Module { return New() },
+	})
+}
+
+func New() *Haproxy {
+	return &Haproxy{
+		Config: Config{
+			HTTP: web.HTTP{
+				Request: web.Request{
+					URL: "http://127.0.0.1:8404/metrics",
+				},
+				Client: web.Client{
+					Timeout: web.Duration{Duration: time.Second},
+				},
+			},
+		},
+
+		charts:          charts.Copy(),
+		proxies:         make(map[string]bool),
+		validateMetrics: true,
+	}
+}
+
+type Config struct {
+	web.HTTP `yaml:",inline"`
+}
+
+type Haproxy struct {
+	module.Base
+	Config `yaml:",inline"`
+
+	charts *module.Charts
+
+	prom            prometheus.Prometheus
+	validateMetrics bool
+	proxies         map[string]bool
+}
+
+func (h *Haproxy) Init() bool {
+	if err := h.validateConfig(); err != nil {
+		h.Errorf("config validation: %v", err)
+		return false
+	}
+
+	prom, err := h.initPrometheusClient()
+	if err != nil {
+		h.Errorf("prometheus client initialization: %v", err)
+		return false
+	}
+	h.prom = prom
+
+	return true
+}
+
+func (h *Haproxy) Check() bool {
+	return len(h.Collect()) > 0
+}
+
+func (h *Haproxy) Charts() *module.Charts {
+	return h.charts
+}
+
+func (h *Haproxy) Collect() map[string]int64 {
+	ms, err := h.collect()
+	if err != nil {
+		h.Error(err)
+		return nil
+	}
+
+	if len(ms) == 0 {
+		return nil
+	}
+	return ms
+}
+
+func (Haproxy) Cleanup() {
+	// TODO: close http idle connections
+}
diff --git a/src/go/collectors/go.d.plugin/modules/haproxy/haproxy_test.go b/src/go/collectors/go.d.plugin/modules/haproxy/haproxy_test.go
new file mode 100644
index 0000000000..c881c19f37
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/modules/haproxy/haproxy_test.go
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package haproxy
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"testing"
+
+	"github.com/netdata/go.d.plugin/pkg/tlscfg"
+	"github.com/netdata/go.d.plugin/pkg/web"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+var (
+	v2310Metrics, _ = os.ReadFile("testdata/v2.3.10/metrics.txt")
+)
+
+func Test_Testdata(t *testing.T) {
+	for name, data := range map[string][]byte{
+		"v2310Metrics": v2310Metrics,
+	} {
+		require.NotNilf(t, data, name)
+	}
+}
+
+func TestNew(t *testing.T) {
+	assert.IsType(t, (*Haproxy)(nil), New())
+}
+
+func TestHaproxy_Init(t *testing.T) {
+	tests := map[string]struct {
+		config   Config
+		wantFail bool
+	}{
+		"success on default config": {
+			config: New().Config,
+		},
+		"fails on unset 'url'": {
+			wantFail: true,
+			config: Config{HTTP: web.HTTP{
+				Request: web.Request{},
+			}},
+		},
+		"fails on invalid TLSCA": {
+			wantFail: true,
+			config: Config{
+				HTTP: web.HTTP{
+					Client: web.Client{
+						TLSConfig: tlscfg.TLSConfig{TLSCA: "testdata/tls"},
+					},
+				}},
+		},
+	}
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			rdb := New()
+			rdb.Config = test.config
+
+			if test.wantFail {
+				assert.False(t, rdb.Init())
+			} else {
+				assert.True(t, rdb.Init())
+			}
+		})
+	}
+}
+
+func TestHaproxy_Charts(t *testing.T) {
+	assert.NotNil(t, New().Charts())
+}
+
+func TestHaproxy_Cleanup(t *testing.T) {
+	assert.NotPanics(t, New().Cleanup)
+}
+
+func TestHaproxy_Check(t *testing.T) {
+	tests := map[string]struct {
+		wantFail bool
+		prepare  func(t *testing.T) (h *Haproxy, cleanup func())
+	}{
+		"success on valid response v2.3.1": {
+			wantFail: false,
+			prepare:  prepareCaseHaproxyV231Metrics,
+		},
+		"fails on response with unexpected metrics (not HAProxy)": {
+			wantFail: true,
+			prepare:  prepareCaseNotHaproxyMetrics,
+		},
+		"fails on 404 response": {
+			wantFail: true,
+			prepare:  prepareCase404Response,
+		},
+		"fails on connection refused": {
+			wantFail: true,
+			prepare:  prepareCaseConnectionRefused,
+		},
+	}
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			h, cleanup := test.prepare(t)
+			defer cleanup()
+
+			if test.wantFail {
+				assert.False(t, h.Check())
+			} else {
+				assert.True(t, h.Check())
+			}
+		})
+	}
+}
+
+func TestHaproxy_Collect(t *testing.T) {
+	tests := map[string]struct {
+		prepare       func(t *testing.T) (h *Haproxy, cleanup func())
+		wantCollected map[string]int64
+	}{
+		"success on valid response v2.3.1": {
+			prepare: prepareCaseHaproxyV231Metrics,
+			wantCollected: map[string]int64{
+				"haproxy_backend_bytes_in_proxy_proxy1":              21057046294,
+				"haproxy_backend_bytes_in_proxy_proxy2":              2493759083896,
+				"haproxy_backend_bytes_out_proxy_proxy1":             41352782609,
+				"haproxy_backend_bytes_out_proxy_proxy2":             5131407558,
+				"haproxy_backend_current_queue_proxy_proxy1":         1,
+				"haproxy_backend_current_queue_proxy_proxy2":         1,
+				"haproxy_backend_current_sessions_proxy_proxy1":      1,
+				"haproxy_backend_current_sessions_proxy_proxy2":      1322,
+				"haproxy_backend_http_responses_1xx_proxy_proxy1":    1,
+				"haproxy_backend_http_responses_1xx_proxy_proxy2":    4130401,
+				"haproxy_backend_http_responses_2xx_proxy_proxy1":    21338013,
+				"haproxy_backend_http_responses_2xx_proxy_proxy2":    1,
+				"haproxy_backend_http_responses_3xx_proxy_proxy1":    10004,
+				"haproxy_backend_http_responses_3xx_proxy_proxy2":    1,
+				"haproxy_backend_http_responses_4xx_proxy_proxy1":    10170758,
+				"haproxy_backend_http_responses_4xx_proxy_proxy2":    1,
+				"haproxy_backend_http_responses_5xx_proxy_proxy1":    3075,
+				"haproxy_backend_http_responses_5xx_proxy_proxy2":    1,
+				"haproxy_backend_http_responses_other_proxy_proxy1":  5657,
+				"haproxy_backend_http_responses_other_proxy_proxy2":  1,
+				"haproxy_backend_queue_time_average_proxy_proxy1":    0,
+				"haproxy_backend_queue_time_average_proxy_proxy2":    0,
+				"haproxy_backend_response_time_average_proxy_proxy1": 52,
+				"haproxy_backend_response_time_average_proxy_proxy2": 1,
+				"haproxy_backend_sessions_proxy_proxy1":              31527507,
+				"haproxy_backend_sessions_proxy_proxy2":              4131723,
+			},
+		},
+		"fails on response with unexpected metrics (not HAProxy)": {
+			prepare: prepareCaseNotHaproxyMetrics,
+		},
+		"fails on 404 response": {
+			prepare: prepareCase404Response,
+		},
+		"fails on connection refused": {
+			prepare: prepareCaseConnectionRefused,
+		},
+	}
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			h, cleanup := test.prepare(t)
+			defer cleanup()
+
+			ms := h.Collect()
+
+			assert.Equal(t, test.wantCollected, ms)
+			if len(test.wantCollected) > 0 {
+				ensureCollectedHasAllChartsDimsVarsIDs(t, h, ms)
+			}
+		})
+	}
+}
+
+func prepareCaseHaproxyV231Metrics(t *testing.T) (*Haproxy, func()) {
+	t.Helper()
+	srv := httptest.NewServer(http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			_, _ = w.Write(v2310Metrics)
+		}))
+	h := New()
+	h.URL = srv.URL
+	require.True(t, h.Init())
+
+	return h, srv.Close
+}
+
+func prepareCaseNotHaproxyMetrics(t *testing.T) (*Haproxy, func()) {
+	t.Helper()
+	srv := httptest.NewServer(http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			_, _ = w.Write([]byte(`
+# HELP haproxy_backend_http_responses_total Total number of HTTP responses.
+# TYPE haproxy_backend_http_responses_total counter
+application_backend_http_responses_total{proxy="infra-traefik-web",code="1xx"} 0
+application_backend_http_responses_total{proxy="infra-vernemq-ws",code="1xx"} 4130401
+application_backend_http_responses_total{proxy="infra-traefik-web",code="2xx"} 21338013
+application_backend_http_responses_total{proxy="infra-vernemq-ws",code="2xx"} 0
+application_backend_http_responses_total{proxy="infra-traefik-web",code="3xx"} 10004
+application_backend_http_responses_total{proxy="infra-vernemq-ws",code="3xx"} 0
+application_backend_http_responses_total{proxy="infra-traefik-web",code="4xx"} 10170758
+application_backend_http_responses_total{proxy="infra-vernemq-ws",code="4xx"} 0
+application_backend_http_responses_total{proxy="infra-traefik-web",code="5xx"} 3075
+application_backend_http_responses_total{proxy="infra-vernemq-ws",code="5xx"} 0
+application_backend_http_responses_total{proxy="infra-traefik-web",code="other"} 5657
+application_backend_http_responses_total{proxy="infra-vernemq-ws",code="other"} 0
+`))
+		}))
+	h := New()
+	h.URL = srv.URL
+	require.True(t, h.Init())
+
+	return h, srv.Close
+}
+
+func prepareCase404Response(t *testing.T) (*Haproxy, func()) {
+	t.Helper()
+	srv := httptest.NewServer(http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			w.WriteHeader(http.StatusNotFound)
+		}))
+	h := New()
+	h.URL = srv.URL
+	require.True(t, h.Init())
+
+	return h, srv.Close
+}
+
+func prepareCaseConnectionRefused(t *testing.T) (*Haproxy, func()) {
+	t.Helper()
+	h := New()
+	h.URL = "http://127.0.0.1:38001"
+	require.True(t, h.Init())
+
+	return h, func() {}
+}
+
+func ensureCollectedHasAllChartsDimsVarsIDs(t *testing.T, h *Haproxy, ms map[string]int64) {
+	for _, chart := range *h.Charts() {
+		if chart.Obsolete {
+			continue
+		}
+		for _, dim := range chart.Dims {
+			_, ok := ms[dim.ID]
+			assert.Truef(t, ok, "chart '%s' dim '%s': no dim in collected", dim.ID, chart.ID)
+		}
+		for _, v := range chart.Vars {
+			_, ok := ms[v.ID]
+			assert.Truef(t, ok, "chart '%s' dim '%s': no dim in collected", v.ID, chart.ID)
+		}
+	}
+}
diff --git a/src/go/collectors/go.d.plugin/modules/haproxy/init.go b/src/go/collectors/go.d.plugin/modules/haproxy/init.go
new file mode 100644
index 0000000000..30e0c45604
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/modules/haproxy/init.go
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package haproxy
+
+import (
+	"errors"
+
+	"github.com/netdata/go.d.plugin/pkg/prometheus"
+	"github.com/netdata/go.d.plugin/pkg/prometheus/selector"
+	"github.com/netdata/go.d.plugin/pkg/web"
+)
+
+func (h Haproxy) validateConfig() error {
+	if h.URL == "" {
+		return errors.New("'url' is not set")
+	}
+	if _, err := web.NewHTTPRequest(h.Request); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (h Haproxy) initPrometheusClient() (prometheus.Prometheus, error) {
+	httpClient, err := web.NewHTTPClient(h.Client)
+	if err != nil {
+		return nil, err
+	}
+
+	prom := prometheus.NewWithSelector(httpClient, h.Request, sr)
+	return prom, nil
+}
+
+var sr, _ = selector.Expr{
+	Allow: []string{
+		metricBackendHTTPResponsesTotal,
+		metricBackendCurrentQueue,
+		metricBackendQueueTimeAverageSeconds,
+		metricBackendBytesInTotal,
+		metricBackendResponseTimeAverageSeconds,
+		metricBackendSessionsTotal,
+		metricBackendCurrentSessions,
+		metricBackendBytesOutTotal,
+	},
+}.Parse()
diff --git a/src/go/collectors/go.d.plugin/modules/haproxy/integrations/haproxy.md b/src/go/collectors/go.d.plugin/modules/haproxy/integrations/haproxy.md
new file mode 100644
index 0000000000..d4cf4146fc
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/modules/haproxy/integrations/haproxy.md
@@ -0,0 +1,241 @@
+<!--startmeta
+custom_edit_url: "https://github.com/netdata/go.d.plugin/edit/master/modules/haproxy/README.md"
+meta_yaml: "https://github.com/netdata/go.d.plugin/edit/master/modules/haproxy/metadata.yaml"
+sidebar_label: "HAProxy"
+learn_status: "Published"
+learn_rel_path: "Data Collection/Web Servers and Web Proxies"
+most_popular: False
+message: "DO NOT EDIT THIS FILE DIRECTLY, IT IS GENERATED BY THE COLLECTOR'S metadata.yaml FILE"
+endmeta-->
+
+# HAProxy
+
+
+<img src="https://netdata.cloud/img/haproxy.svg" width="150"/>
+
+
+Plugin: go.d.plugin
+Module: haproxy
+
+<img src="https://img.shields.io/badge/maintained%20by-Netdata-%2300ab44" />
+
+## Overview
+
+This collector monitors HAProxy servers.
+
+
+
+
+This collector is supported on all platforms.
+
+This collector supports collecting metrics from multiple instances of this integration, including remote instances.
+
+
+### Default Behavior
+
+#### Auto-Detection
+
+This integration doesn't support auto-detection.
+
+#### Limits
+
+The default configuration for this integration does not impose any limits on data collection.
+
+#### Performance Impact
+
+The default configuration for this integration is not expected to impose a significant performance impact on the system.
+
+
+## Metrics
+
+Metrics grouped by *scope*.
+
+The scope defines the instance that the metric belongs to. An instance is uniquely identified by a set of labels.
+
+
+
+### Per HAProxy instance
+
+These metrics refer to the entire monitored application.
+
+This scope has no labels.
+
+Metrics:
+
+| Metric | Dimensions | Unit |
+|:------|:----------|:----|
+| haproxy.backend_current_sessions | a dimension per proxy | sessions |
+| haproxy.backend_sessions | a dimension per proxy | sessions/s |
+| haproxy.backend_response_time_average | a dimension per proxy | milliseconds |
+| haproxy.backend_queue_time_average | a dimension per proxy | milliseconds |
+| haproxy.backend_current_queue | a dimension per proxy | requests |
+
+### Per proxy
+
+These metrics refer to the Proxy.
+
+This scope has no labels.
+
+Metrics:
+
+| Metric | Dimensions | Unit |
+|:------|:----------|:----|
+| haproxy.backend_http_responses | 1xx, 2xx, 3xx, 4xx, 5xx, other | responses/s |
+| haproxy.backend_network_io | in, out | bytes/s |
+
+
+
+## Alerts
+
+There are no alerts configured by default for this integration.
+
+
+## Setup
+
+### Prerequisites
+
+#### Enable PROMEX addon.
+
+To enable PROMEX addon, follow the [official documentation](https://github.com/haproxy/haproxy/tree/master/addons/promex).
+
+
+
+### Configuration
+
+#### File
+
+The configuration file name for this integration is `go.d/haproxy.conf`.
+
+
+You can edit the configuration file using the `edit-config` script from the
+Netdata [config directory](https://github.com/netdata/netdata/blob/master/docs/configure/nodes.md#the-netdata-config-directory).
+
+```bash
+cd /etc/netdata 2>/dev/null || cd /opt/netdata/etc/netdata
+sudo ./edit-config go.d/haproxy.conf
+```
+#### Options
+
+The following options can be defined globally: update_every, autodetection_retry.
+
+
+<details><summary>Config options</summary>
+
+| Name | Description | Default | Required |
+|:----|:-----------|:-------|:--------:|
+| update_every | Data collection frequency. | 1 | no |
+| autodetection_retry | Recheck interval in seconds. Zero means no recheck will be scheduled. | 0 | no |
+| url | Server URL. | http://127.0.0.1 | yes |
+| timeout | HTTP request timeout. | 1 | no |
+| username | Username for basic HTTP authentication. |  | no |
+| password | Password for basic HTTP authentication. |  | no |
+| proxy_url | Proxy URL. |  | no |
+| proxy_username | Username for proxy basic HTTP authentication. |  | no |
+| proxy_password | Password for proxy basic HTTP authentication. |  | no |
+| method | HTTP request method. | GET | no |
+| body | HTTP request body. |  | no |
+| headers | HTTP request headers. |  | no |
+| not_follow_redirects | Redirect handling policy. Controls whether the client follows redirects. | no | no |
+| tls_skip_verify | Server certificate chain and hostname validation policy. Controls whether the client performs this check. | no | no |
+| tls_ca | Certification authority that the client uses when verifying the server's certificates. |  | no |
+| tls_cert | Client TLS certificate. |  | no |
+| tls_key | Client TLS key. |  | no |
+
+</details>
+
+#### Examples
+
+##### Basic
+
+A basic example configuration.
+
+<details><summary>Config</summary>
+
+```yaml
+jobs:
+  - name: local
+    url: http://127.0.0.1:8404/metrics
+
+```
+</details>
+
+##### HTTP authentication
+
+Basic HTTP authentication.
+
+<details><summary>Config</summary>
+
+```yaml
+jobs:
+  - name: local
+    url: http://127.0.0.1:8404/metrics
+    username: username
+    password: password
+
+```
+</details>
+
+##### HTTPS with self-signed certificate
+
+NGINX Plus with enabled HTTPS and self-signed certificate.
+
+<details><summary>Config</summary>
+
+```yaml
+jobs:
+  - name: local
+    url: https://127.0.0.1:8404/metrics
+    tls_skip_verify: yes
+
+```
+</details>
+
+##### Multi-instance
+
+> **Note**: When you define multiple jobs, their names must be unique.
+
+Collecting metrics from local and remote instances.
+
+
+<details><summary>Config</summary>
+
+```yaml
+jobs:
+  - name: local
+    url: http://127.0.0.1:8404/metrics
+
+  - name: remote
+    url: http://192.0.2.1:8404/metrics
+
+```
+</details>
+
+
+
+## Troubleshooting
+
+### Debug Mode
+
+To troubleshoot issues with the `haproxy` collector, run the `go.d.plugin` with the debug option enabled. The output
+should give you clues as to why the collector isn't working.
+
+- Navigate to the `plugins.d` directory, usually at `/usr/libexec/netdata/plugins.d/`. If that's not the case on
+  your system, open `netdata.conf` and look for the `plugins` setting under `[directories]`.
+
+  ```bash
+  cd /usr/libexec/netdata/plugins.d/
+  ```
+
+- Switch to the `netdata` user.
+
+  ```bash
+  sudo -u netdata -s
+  ```
+
+- Run the `go.d.plugin` to debug the collector:
+
+  ```bash
+  ./go.d.plugin -d -m haproxy
+  ```
+
+
diff --git a/src/go/collectors/go.d.plugin/modules/haproxy/metadata.yaml b/src/go/collectors/go.d.plugin/modules/haproxy/metadata.yaml
new file mode 100644
index 0000000000..adc8796020
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/modules/haproxy/metadata.yaml
@@ -0,0 +1,231 @@
+plugin_name: go.d.plugin
+modules:
+  - meta:
+