fix lint

internal/apps/agent/observability/collector.go

@@ -1,3 +1,4 @@
+// Package observability provides system and service level observability data collection for the agent.
 package observability
 
 import (
@@ -15,6 +16,9 @@ import (
 	edgeobs "github.com/Rain-kl/Wavelet/internal/apps/edge/observability"
 )
 
+const nodeHealthEventInitialCapacity = 2
+
+// BuildProfile collects the system profile and returns it only if the fingerprint has changed.
 func BuildProfile(cfg *config.Config, stateStore *state.Store) *protocol.NodeSystemProfile {
 	profile := collectProfile(cfg)
 	if profile == nil {
@@ -38,6 +42,7 @@ func BuildProfile(cfg *config.Config, stateStore *state.Store) *protocol.NodeSys
 	return profile
 }
 
+// BuildSnapshot captures current system metrics and returns a metric snapshot.
 func BuildSnapshot(cfg *config.Config, stateStore *state.Store) *protocol.NodeMetricSnapshot {
 	now := time.Now().UTC()
 	metric := &protocol.NodeMetricSnapshot{
@@ -79,6 +84,7 @@ func BuildSnapshot(cfg *config.Config, stateStore *state.Store) *protocol.NodeMe
 	return metric
 }
 
+// BuildOpenrestyObservation builds the OpenResty observation protocol model from the managed metrics.
 func BuildOpenrestyObservation(managed *ManagedOpenRestyMetrics) *protocol.NodeOpenrestyObservation {
 	if managed == nil {
 		return nil
@@ -91,11 +97,12 @@ func BuildOpenrestyObservation(managed *ManagedOpenRestyMetrics) *protocol.NodeO
 	}
 }
 
+// BuildHealthEvents converts system snapshot health state into a list of health events.
 func BuildHealthEvents(snapshot *state.Snapshot) []protocol.NodeHealthEvent {
 	if snapshot == nil {
 		return []protocol.NodeHealthEvent{}
 	}
-	events := make([]protocol.NodeHealthEvent, 0, 2)
+	events := make([]protocol.NodeHealthEvent, 0, nodeHealthEventInitialCapacity)
 	nowUnix := time.Now().UTC().Unix()
 	if strings.TrimSpace(snapshot.OpenrestyStatus) == protocol.OpenrestyStatusUnhealthy {
 		events = append(events, protocol.NodeHealthEvent{
@@ -147,4 +154,4 @@ func fingerprintProfile(profile *protocol.NodeSystemProfile) string {
 	}
 	sum := sha256.Sum256(raw)
 	return hex.EncodeToString(sum[:])
-}
+}

internal/apps/agent/observability/openresty_local.go

@@ -1,6 +1,7 @@
 package observability
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -14,11 +15,15 @@ import (
 	"github.com/Rain-kl/Wavelet/internal/apps/agent/protocol"
 )
 
-const openRestyObservabilityPath = "/openflare/observability"
-const openRestyStubStatusPath = "/openflare/stub_status"
+const (
+	openRestyObservabilityPath      = "/openflare/observability"
+	openRestyStubStatusPath         = "/openflare/stub_status"
+	stubStatusActiveMatchGroupCount = 2
+)
 
 var stubStatusActivePattern = regexp.MustCompile(`Active connections:\s+(\d+)`)
 
+// ManagedOpenRestyMetrics holds metrics collected from the local OpenResty instance.
 type ManagedOpenRestyMetrics struct {
 	TrafficReport        *protocol.NodeTrafficReport
 	OpenrestyRxBytes     int64
@@ -39,7 +44,8 @@ type openRestyObservabilityResponse struct {
 	OpenrestyTxBytes    int64            `json:"openresty_tx_bytes"`
 }
 
-func CollectManagedOpenRestyMetrics(cfg *config.Config) *ManagedOpenRestyMetrics {
+// CollectManagedOpenRestyMetrics collects metrics from the local OpenResty observability endpoints.
+func CollectManagedOpenRestyMetrics(ctx context.Context, cfg *config.Config) *ManagedOpenRestyMetrics {
 	if cfg == nil || cfg.OpenrestyObservabilityPort <= 0 {
 		return nil
 	}
@@ -48,7 +54,7 @@ func CollectManagedOpenRestyMetrics(cfg *config.Config) *ManagedOpenRestyMetrics
 	client := &http.Client{Timeout: 1500 * time.Millisecond}
 
 	observabilityResp := openRestyObservabilityResponse{}
-	if err := fetchLocalJSON(client, baseURL+openRestyObservabilityPath, &observabilityResp); err != nil {
+	if err := fetchLocalJSON(ctx, client, baseURL+openRestyObservabilityPath, &observabilityResp); err != nil {
 		return nil
 	}
 
@@ -67,31 +73,39 @@ func CollectManagedOpenRestyMetrics(cfg *config.Config) *ManagedOpenRestyMetrics
 		OpenrestyTxBytes: observabilityResp.OpenrestyTxBytes,
 	}
 
-	if text, err := fetchLocalText(client, baseURL+openRestyStubStatusPath); err == nil {
+	if text, err := fetchLocalText(ctx, client, baseURL+openRestyStubStatusPath); err == nil {
 		result.OpenrestyConnections = parseStubStatusActiveConnections(text)
 	}
 
 	return result
 }
 
-func fetchLocalJSON(client *http.Client, url string, target any) error {
-	resp, err := client.Get(url)
+func fetchLocalJSON(ctx context.Context, client *http.Client, url string, target any) error {
+	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
 	if err != nil {
 		return err
 	}
-	defer resp.Body.Close()
+	resp, err := client.Do(req)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = resp.Body.Close() }()
 	if resp.StatusCode != http.StatusOK {
 		return fmt.Errorf("unexpected local observability status: %s", resp.Status)
 	}
 	return json.NewDecoder(resp.Body).Decode(target)
 }
 
-func fetchLocalText(client *http.Client, url string) (string, error) {
-	resp, err := client.Get(url)
+func fetchLocalText(ctx context.Context, client *http.Client, url string) (string, error) {
+	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
 	if err != nil {
 		return "", err
 	}
-	defer resp.Body.Close()
+	resp, err := client.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer func() { _ = resp.Body.Close() }()
 	if resp.StatusCode != http.StatusOK {
 		return "", fmt.Errorf("unexpected local stub status: %s", resp.Status)
 	}
@@ -104,7 +118,7 @@ func fetchLocalText(client *http.Client, url string) (string, error) {
 
 func parseStubStatusActiveConnections(raw string) int64 {
 	matches := stubStatusActivePattern.FindStringSubmatch(raw)
-	if len(matches) != 2 {
+	if len(matches) != stubStatusActiveMatchGroupCount {
 		return 0
 	}
 	value, err := strconv.ParseInt(matches[1], 10, 64)

internal/apps/agent/observability/openresty_local_test.go

@@ -1,6 +1,7 @@
 package observability
 
 import (
+	"context"
 	"net"
 	"net/http"
 	"net/http/httptest"
@@ -31,7 +32,7 @@ func TestCollectManagedOpenRestyMetrics(t *testing.T) {
 	server.Start()
 	defer server.Close()
 
-	metrics := CollectManagedOpenRestyMetrics(&config.Config{
+	metrics := CollectManagedOpenRestyMetrics(context.Background(), &config.Config{
 		OpenrestyObservabilityPort: port,
 	})
 	if metrics == nil || metrics.TrafficReport == nil {
@@ -67,7 +68,7 @@ func TestNormalizeCountMapDropsEmptyKeys(t *testing.T) {
 
 func TestCollectManagedOpenRestyMetricsHandlesUnavailableEndpoint(t *testing.T) {
 	cfg := &config.Config{OpenrestyObservabilityPort: 1}
-	if metrics := CollectManagedOpenRestyMetrics(cfg); metrics != nil {
+	if metrics := CollectManagedOpenRestyMetrics(context.Background(), cfg); metrics != nil {
 		t.Fatalf("expected nil metrics for unavailable endpoint, got %+v", metrics)
 	}
 }

internal/apps/agent/observability/traffic.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"io"
 	"log/slog"
+	"net/http"
 	"os"
 	"regexp"
 	"sort"
@@ -28,6 +29,11 @@ type accessLogRecord struct {
 	RequestLength int64  `json:"request_length"`
 }
 
+const (
+	combinedAccessLogMatchGroupCount = 5
+	trafficTopDomainsLimit           = 8
+)
+
 var combinedAccessLogPattern = regexp.MustCompile(`^(\S+)\s+\S+\s+\S+\s+\[([^]]+)]\s+"\S+\s+(\S+)(?:\s+[^"]*)?"\s+(\d{3})\s+\S+`)
 
 type trafficAggregate struct {
@@ -43,11 +49,13 @@ type trafficAggregate struct {
 	logs             []protocol.NodeAccessLog
 }
 
+// BuildTrafficReport generates a traffic report using access logs or falling back to managed metrics.
 func BuildTrafficReport(cfg *config.Config, stateStore *state.Store, managed *ManagedOpenRestyMetrics) *protocol.NodeTrafficReport {
 	report, _, _ := BuildTrafficObservability(cfg, stateStore, managed)
 	return report
 }
 
+// BuildTrafficObservability returns the traffic report, parsed access logs, and managed metrics.
 func BuildTrafficObservability(cfg *config.Config, stateStore *state.Store, managed *ManagedOpenRestyMetrics) (*protocol.NodeTrafficReport, []protocol.NodeAccessLog, *ManagedOpenRestyMetrics) {
 	if cfg == nil || stateStore == nil {
 		if managed != nil && managed.TrafficReport != nil {
@@ -78,7 +86,7 @@ func readAccessLogDelta(cfg *config.Config, stateStore *state.Store) *trafficAgg
 	}
 
 	logPath := managedAccessLogPath(cfg)
-	file, err := os.Open(logPath)
+	file, err := os.Open(logPath) //nolint:gosec // path is the configured managed access log location
 	if err != nil {
 		if os.IsNotExist(err) {
 			if snapshot.AccessLogOffset != 0 {
@@ -167,7 +175,7 @@ func (aggregate *trafficAggregate) consume(line []byte) {
 	}
 
 	aggregate.requestCount++
-	if record.Status >= 500 {
+	if record.Status >= http.StatusInternalServerError {
 		aggregate.errorCount++
 	}
 	if record.Status > 0 {
@@ -234,7 +242,7 @@ func parseJSONAccessLogRecord(raw string) (parsedAccessLogRecord, bool) {
 
 func parseCombinedAccessLogRecord(raw string) (parsedAccessLogRecord, bool) {
 	matches := combinedAccessLogPattern.FindStringSubmatch(raw)
-	if len(matches) != 5 {
+	if len(matches) != combinedAccessLogMatchGroupCount {
 		return parsedAccessLogRecord{}, false
 	}
 	timestamp, err := parseAccessLogTime(matches[2])
@@ -265,7 +273,7 @@ func (aggregate *trafficAggregate) report() *protocol.NodeTrafficReport {
 		ErrorCount:          aggregate.errorCount,
 		UniqueVisitorCount:  int64(len(aggregate.visitors)),
 		StatusCodes:         cloneTrafficCounts(aggregate.statusCodes, 0),
-		TopDomains:          topCounts(aggregate.topDomains, 8),
+		TopDomains:          topCounts(aggregate.topDomains, trafficTopDomainsLimit),
 		SourceCountries:     map[string]int64{},
 	}
 }