add common generic Get for system-probe checks (#31254)

cmd/system-probe/api/client/client.go

@@ -7,10 +7,16 @@
 package client
 
 import (
+	"encoding/json"
 	"errors"
+	"fmt"
+	"io"
 	"net/http"
+	"net/url"
+	"strings"
 	"time"
 
+	"github.com/DataDog/datadog-agent/cmd/system-probe/config/types"
 	"github.com/DataDog/datadog-agent/pkg/util/funcs"
 )
 
@@ -35,3 +41,47 @@ func get(socketPath string) *http.Client {
 		},
 	}
 }
+
+// GetCheck returns data unmarshalled from JSON to T, from the specified module at the /<module>/check endpoint.
+func GetCheck[T any](client *http.Client, module types.ModuleName) (T, error) {
+	var data T
+	req, err := http.NewRequest("GET", ModuleURL(module, "/check"), nil)
+	if err != nil {
+		return data, err
+	}
+
+	resp, err := client.Do(req)
+	if err != nil {
+		return data, err
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return data, err
+	}
+	if resp.StatusCode != http.StatusOK {
+		return data, fmt.Errorf("non-ok status code: url %s, status_code: %d, response: `%s`", req.URL, resp.StatusCode, string(body))
+	}
+
+	err = json.Unmarshal(body, &data)
+	return data, err
+}
+
+func constructURL(module string, endpoint string) string {
+	u, _ := url.Parse("http://sysprobe")
+	if module != "" {
+		u = u.JoinPath(module)
+	}
+	path, query, found := strings.Cut(endpoint, "?")
+	u = u.JoinPath(path)
+	if found {
+		u.RawQuery = query
+	}
+	return u.String()
+}
+
+// ModuleURL constructs a system-probe ModuleURL given the specified module and endpoint.
+func ModuleURL(module types.ModuleName, endpoint string) string {
+	return constructURL(string(module), endpoint)
+}

cmd/system-probe/api/client/client_test.go

@@ -0,0 +1,53 @@
+// Unless explicitly stated otherwise all files in this repository are licensed
+// under the Apache License Version 2.0.
+// This product includes software developed at Datadog (https://www.datadoghq.com/).
+// Copyright 2024-present Datadog, Inc.
+
+package client
+
+import (
+	"context"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestConstructURL(t *testing.T) {
+	u := constructURL("", "/asdf?a=b")
+	assert.Equal(t, "http://sysprobe/asdf?a=b", u)
+
+	u = constructURL("zzzz", "/asdf?a=b")
+	assert.Equal(t, "http://sysprobe/zzzz/asdf?a=b", u)
+
+	u = constructURL("zzzz", "asdf")
+	assert.Equal(t, "http://sysprobe/zzzz/asdf", u)
+}
+
+func TestGetCheck(t *testing.T) {
+	type testData struct {
+		Str string
+		Num int
+	}
+
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/test/check" {
+			_, _ = w.Write([]byte(`{"Str": "asdf", "Num": 42}`))
+		} else {
+			w.WriteHeader(http.StatusNotFound)
+		}
+	}))
+	t.Cleanup(server.Close)
+
+	client := &http.Client{Transport: &http.Transport{DialContext: func(_ context.Context, _, _ string) (net.Conn, error) {
+		return net.Dial("tcp", server.Listener.Addr().String())
+	}}}
+
+	resp, err := GetCheck[testData](client, "test")
+	require.NoError(t, err)
+	assert.Equal(t, "asdf", resp.Str)
+	assert.Equal(t, 42, resp.Num)
+}

pkg/collector/corechecks/ebpf/ebpf.go

@@ -3,26 +3,27 @@
 // This product includes software developed at Datadog (https://www.datadoghq.com/).
 // Copyright 2016-present Datadog, Inc.
 
-//go:build cgo && linux
+//go:build linux
 
 // Package ebpf contains all the ebpf-based checks.
 package ebpf
 
 import (
 	"fmt"
+	"net/http"
 	"strings"
 
 	"github.com/cihub/seelog"
 	"gopkg.in/yaml.v2"
 
+	sysprobeclient "github.com/DataDog/datadog-agent/cmd/system-probe/api/client"
 	sysconfig "github.com/DataDog/datadog-agent/cmd/system-probe/config"
 	"github.com/DataDog/datadog-agent/comp/core/autodiscovery/integration"
 	"github.com/DataDog/datadog-agent/pkg/aggregator/sender"
 	"github.com/DataDog/datadog-agent/pkg/collector/check"
 	core "github.com/DataDog/datadog-agent/pkg/collector/corechecks"
 	ebpfcheck "github.com/DataDog/datadog-agent/pkg/collector/corechecks/ebpf/probe/ebpfcheck/model"
 	pkgconfigsetup "github.com/DataDog/datadog-agent/pkg/config/setup"
-	processnet "github.com/DataDog/datadog-agent/pkg/process/net"
 	"github.com/DataDog/datadog-agent/pkg/util/log"
 	"github.com/DataDog/datadog-agent/pkg/util/optional"
 )
@@ -38,8 +39,8 @@ type EBPFCheckConfig struct {
 
 // EBPFCheck grabs eBPF map/program/perf buffer metrics
 type EBPFCheck struct {
-	config       *EBPFCheckConfig
-	sysProbeUtil processnet.SysProbeUtil
+	config         *EBPFCheckConfig
+	sysProbeClient *http.Client
 	core.CheckBase
 }
 
@@ -68,26 +69,13 @@ func (m *EBPFCheck) Configure(senderManager sender.SenderManager, _ uint64, conf
 	if err := m.config.Parse(config); err != nil {
 		return fmt.Errorf("ebpf check config: %s", err)
 	}
-	if err := processnet.CheckPath(pkgconfigsetup.SystemProbe().GetString("system_probe_config.sysprobe_socket")); err != nil {
-		return fmt.Errorf("sysprobe socket: %s", err)
-	}
-
+	m.sysProbeClient = sysprobeclient.Get(pkgconfigsetup.SystemProbe().GetString("system_probe_config.sysprobe_socket"))
 	return nil
 }
 
 // Run executes the check
 func (m *EBPFCheck) Run() error {
-	if m.sysProbeUtil == nil {
-		var err error
-		m.sysProbeUtil, err = processnet.GetRemoteSystemProbeUtil(
-			pkgconfigsetup.SystemProbe().GetString("system_probe_config.sysprobe_socket"),
-		)
-		if err != nil {
-			return fmt.Errorf("sysprobe connection: %s", err)
-		}
-	}
-
-	data, err := m.sysProbeUtil.GetCheck(sysconfig.EBPFModule)
+	stats, err := sysprobeclient.GetCheck[ebpfcheck.EBPFStats](m.sysProbeClient, sysconfig.EBPFModule)
 	if err != nil {
 		return fmt.Errorf("get ebpf check: %s", err)
 	}
@@ -97,11 +85,6 @@ func (m *EBPFCheck) Run() error {
 		return fmt.Errorf("get metric sender: %s", err)
 	}
 
-	stats, ok := data.(ebpfcheck.EBPFStats)
-	if !ok {
-		return log.Errorf("ebpf check raw data has incorrect type: %T", stats)
-	}
-
 	totalMapMaxSize, totalMapRSS := uint64(0), uint64(0)
 	moduleTotalMapMaxSize, moduleTotalMapRSS := make(map[string]uint64), make(map[string]uint64)
 	reportBaseMap := func(mapStats ebpfcheck.EBPFMapStats) {

pkg/collector/corechecks/ebpf/oomkill/oom_kill.go

@@ -3,21 +3,19 @@
 // This product includes software developed at Datadog (https://www.datadoghq.com/).
 // Copyright 2016-present Datadog, Inc.
 
-// FIXME: we require the `cgo` build tag because of this dep relationship:
-// github.com/DataDog/datadog-agent/pkg/process/net depends on `github.com/DataDog/agent-payload/v5/process`,
-// which has a hard dependency on `github.com/DataDog/zstd_0`, which requires CGO.
-// Should be removed once `github.com/DataDog/agent-payload/v5/process` can be imported with CGO disabled.
-//go:build cgo && linux
+//go:build linux
 
 // Package oomkill contains the OOMKill check.
 package oomkill
 
 import (
 	"fmt"
+	"net/http"
 	"strings"
 
 	yaml "gopkg.in/yaml.v2"
 
+	sysprobeclient "github.com/DataDog/datadog-agent/cmd/system-probe/api/client"
 	sysconfig "github.com/DataDog/datadog-agent/cmd/system-probe/config"
 	"github.com/DataDog/datadog-agent/comp/core/autodiscovery/integration"
 	tagger "github.com/DataDog/datadog-agent/comp/core/tagger/def"
@@ -28,7 +26,6 @@ import (
 	"github.com/DataDog/datadog-agent/pkg/collector/corechecks/ebpf/probe/oomkill/model"
 	pkgconfigsetup "github.com/DataDog/datadog-agent/pkg/config/setup"
 	"github.com/DataDog/datadog-agent/pkg/metrics/event"
-	process_net "github.com/DataDog/datadog-agent/pkg/process/net"
 	"github.com/DataDog/datadog-agent/pkg/util/cgroups"
 	"github.com/DataDog/datadog-agent/pkg/util/log"
 	"github.com/DataDog/datadog-agent/pkg/util/optional"
@@ -47,8 +44,9 @@ type OOMKillConfig struct {
 // OOMKillCheck grabs OOM Kill metrics
 type OOMKillCheck struct {
 	core.CheckBase
-	instance *OOMKillConfig
-	tagger   tagger.Component
+	instance       *OOMKillConfig
+	tagger         tagger.Component
+	sysProbeClient *http.Client
 }
 
 // Factory creates a new check factory
@@ -80,6 +78,7 @@ func (m *OOMKillCheck) Configure(senderManager sender.SenderManager, _ uint64, c
 	if err != nil {
 		return err
 	}
+	m.sysProbeClient = sysprobeclient.Get(pkgconfigsetup.SystemProbe().GetString("system_probe_config.sysprobe_socket"))
 
 	return m.instance.Parse(config)
 }
@@ -90,13 +89,7 @@ func (m *OOMKillCheck) Run() error {
 		return nil
 	}
 
-	sysProbeUtil, err := process_net.GetRemoteSystemProbeUtil(
-		pkgconfigsetup.SystemProbe().GetString("system_probe_config.sysprobe_socket"))
-	if err != nil {
-		return err
-	}
-
-	data, err := sysProbeUtil.GetCheck(sysconfig.OOMKillProbeModule)
+	oomkillStats, err := sysprobeclient.GetCheck[[]model.OOMKillStats](m.sysProbeClient, sysconfig.OOMKillProbeModule)
 	if err != nil {
 		return err
 	}
@@ -109,10 +102,6 @@ func (m *OOMKillCheck) Run() error {
 
 	triggerType := ""
 	triggerTypeText := ""
-	oomkillStats, ok := data.([]model.OOMKillStats)
-	if !ok {
-		return log.Errorf("Raw data has incorrect type")
-	}
 	for _, line := range oomkillStats {
 		containerID, err := cgroups.ContainerFilter("", line.CgroupName)
 		if err != nil || containerID == "" {

pkg/collector/corechecks/ebpf/tcpqueuelength/tcp_queue_length.go

@@ -3,18 +3,17 @@
 // This product includes software developed at Datadog (https://www.datadoghq.com/).
 // Copyright 2016-present Datadog, Inc.
 
-// FIXME: we require the `cgo` build tag because of this dep relationship:
-// github.com/DataDog/datadog-agent/pkg/process/net depends on `github.com/DataDog/agent-payload/v5/process`,
-// which has a hard dependency on `github.com/DataDog/zstd_0`, which requires CGO.
-// Should be removed once `github.com/DataDog/agent-payload/v5/process` can be imported with CGO disabled.
-//go:build cgo && linux
+//go:build linux
 
-//nolint:revive // TODO(PLINT) Fix revive linter
+// Package tcpqueuelength contains the TCP Queue Length check
 package tcpqueuelength
 
 import (
-	yaml "gopkg.in/yaml.v2"
+	"net/http"
 
+	"gopkg.in/yaml.v2"
+
+	sysprobeclient "github.com/DataDog/datadog-agent/cmd/system-probe/api/client"
 	sysconfig "github.com/DataDog/datadog-agent/cmd/system-probe/config"
 	"github.com/DataDog/datadog-agent/comp/core/autodiscovery/integration"
 	tagger "github.com/DataDog/datadog-agent/comp/core/tagger/def"
@@ -24,7 +23,6 @@ import (
 	core "github.com/DataDog/datadog-agent/pkg/collector/corechecks"
 	"github.com/DataDog/datadog-agent/pkg/collector/corechecks/ebpf/probe/tcpqueuelength/model"
 	pkgconfigsetup "github.com/DataDog/datadog-agent/pkg/config/setup"
-	process_net "github.com/DataDog/datadog-agent/pkg/process/net"
 	"github.com/DataDog/datadog-agent/pkg/util/cgroups"
 	"github.com/DataDog/datadog-agent/pkg/util/log"
 	"github.com/DataDog/datadog-agent/pkg/util/optional"
@@ -43,8 +41,9 @@ type TCPQueueLengthConfig struct {
 // TCPQueueLengthCheck grabs TCP queue length metrics
 type TCPQueueLengthCheck struct {
 	core.CheckBase
-	instance *TCPQueueLengthConfig
-	tagger   tagger.Component
+	instance       *TCPQueueLengthConfig
+	tagger         tagger.Component
+	sysProbeClient *http.Client
 }
 
 // Factory creates a new check factory
@@ -76,6 +75,7 @@ func (t *TCPQueueLengthCheck) Configure(senderManager sender.SenderManager, _ ui
 	if err != nil {
 		return err
 	}
+	t.sysProbeClient = sysprobeclient.Get(pkgconfigsetup.SystemProbe().GetString("system_probe_config.sysprobe_socket"))
 
 	return t.instance.Parse(config)
 }
@@ -86,13 +86,7 @@ func (t *TCPQueueLengthCheck) Run() error {
 		return nil
 	}
 
-	sysProbeUtil, err := process_net.GetRemoteSystemProbeUtil(
-		pkgconfigsetup.SystemProbe().GetString("system_probe_config.sysprobe_socket"))
-	if err != nil {
-		return err
-	}
-
-	data, err := sysProbeUtil.GetCheck(sysconfig.TCPQueueLengthTracerModule)
+	stats, err := sysprobeclient.GetCheck[model.TCPQueueLengthStats](t.sysProbeClient, sysconfig.TCPQueueLengthTracerModule)
 	if err != nil {
 		return err
 	}
@@ -102,11 +96,6 @@ func (t *TCPQueueLengthCheck) Run() error {
 		return err
 	}
 
-	stats, ok := data.(model.TCPQueueLengthStats)
-	if !ok {
-		return log.Errorf("Raw data has incorrect type")
-	}
-
 	for k, v := range stats {
 		containerID, err := cgroups.ContainerFilter("", k)
 		if err != nil || containerID == "" {