fix(http): Stop plugins from leaking file descriptors on telegraf reload (#15213)

plugins/inputs/ctrlx_datalayer/ctrlx_datalayer.go

@@ -353,6 +353,9 @@ func (c *CtrlXDataLayer) gatherLoop(ctx context.Context) {
 func (c *CtrlXDataLayer) Stop() {
 	c.cancel()
 	c.wg.Wait()
+	if c.connection != nil {
+		c.connection.CloseIdleConnections()
+	}
 }
 
 // Gather is called by telegraf to collect the metrics.

plugins/inputs/elasticsearch/elasticsearch.go

@@ -185,6 +185,10 @@ func (e *Elasticsearch) Init() error {
 	return nil
 }
 
+func (e *Elasticsearch) Start(_ telegraf.Accumulator) error {
+	return nil
+}
+
 // Gather reads the stats from Elasticsearch and writes it to the
 // Accumulator.
 func (e *Elasticsearch) Gather(acc telegraf.Accumulator) error {
@@ -282,6 +286,12 @@ func (e *Elasticsearch) Gather(acc telegraf.Accumulator) error {
 	return nil
 }
 
+func (e *Elasticsearch) Stop() {
+	if e.client != nil {
+		e.client.CloseIdleConnections()
+	}
+}
+
 func (e *Elasticsearch) createHTTPClient() (*http.Client, error) {
 	ctx := context.Background()
 	if e.HTTPTimeout != 0 {

plugins/inputs/elasticsearch_query/elasticsearch_query.go

@@ -173,6 +173,10 @@ func (e *ElasticsearchQuery) connectToES() error {
 	return nil
 }
 
+func (e *ElasticsearchQuery) Start(_ telegraf.Accumulator) error {
+	return nil
+}
+
 // Gather writes the results of the queries from Elasticsearch to the Accumulator.
 func (e *ElasticsearchQuery) Gather(acc telegraf.Accumulator) error {
 	var wg sync.WaitGroup
@@ -197,6 +201,12 @@ func (e *ElasticsearchQuery) Gather(acc telegraf.Accumulator) error {
 	return nil
 }
 
+func (e *ElasticsearchQuery) Stop() {
+	if e.httpclient != nil {
+		e.httpclient.CloseIdleConnections()
+	}
+}
+
 func (e *ElasticsearchQuery) createHTTPClient() (*http.Client, error) {
 	ctx := context.Background()
 	return e.HTTPClientConfig.CreateClient(ctx, e.Log)

plugins/inputs/http/http.go

@@ -80,6 +80,10 @@ func (h *HTTP) Init() error {
 	return nil
 }
 
+func (h *HTTP) Start(_ telegraf.Accumulator) error {
+	return nil
+}
+
 // Gather takes in an accumulator and adds the metrics that the Input
 // gathers. This is called every "interval"
 func (h *HTTP) Gather(acc telegraf.Accumulator) error {
@@ -99,6 +103,12 @@ func (h *HTTP) Gather(acc telegraf.Accumulator) error {
 	return nil
 }
 
+func (h *HTTP) Stop() {
+	if h.client != nil {
+		h.client.CloseIdleConnections()
+	}
+}
+
 // SetParserFunc takes the data_format from the config and finds the right parser for that format
 func (h *HTTP) SetParserFunc(fn telegraf.ParserFunc) {
 	h.parserFunc = fn

plugins/inputs/kibana/kibana.go

@@ -123,6 +123,10 @@ func (*Kibana) SampleConfig() string {
 	return sampleConfig
 }
 
+func (k *Kibana) Start(_ telegraf.Accumulator) error {
+	return nil
+}
+
 func (k *Kibana) Gather(acc telegraf.Accumulator) error {
 	if k.client == nil {
 		client, err := k.createHTTPClient()
@@ -150,6 +154,12 @@ func (k *Kibana) Gather(acc telegraf.Accumulator) error {
 	return nil
 }
 
+func (k *Kibana) Stop() {
+	if k.client != nil {
+		k.client.CloseIdleConnections()
+	}
+}
+
 func (k *Kibana) createHTTPClient() (*http.Client, error) {
 	ctx := context.Background()
 	return k.HTTPClientConfig.CreateClient(ctx, k.Log)

plugins/inputs/logstash/logstash.go

@@ -454,6 +454,10 @@ func (logstash *Logstash) gatherPipelinesStats(address string, accumulator teleg
 	return nil
 }
 
+func (logstash *Logstash) Start(_ telegraf.Accumulator) error {
+	return nil
+}
+
 // Gather ask this plugin to start gathering metrics
 func (logstash *Logstash) Gather(accumulator telegraf.Accumulator) error {
 	if logstash.client == nil {
@@ -508,6 +512,12 @@ func (logstash *Logstash) Gather(accumulator telegraf.Accumulator) error {
 	return nil
 }
 
+func (logstash *Logstash) Stop() {
+	if logstash.client != nil {
+		logstash.client.CloseIdleConnections()
+	}
+}
+
 // init registers this plugin instance
 func init() {
 	inputs.Add("logstash", func() telegraf.Input {

plugins/inputs/openstack/openstack.go

@@ -15,6 +15,7 @@ import (
 	_ "embed"
 	"errors"
 	"fmt"
+	"net/http"
 	"regexp"
 	"sort"
 	"strconv"
@@ -79,6 +80,8 @@ type OpenStack struct {
 	Log              telegraf.Logger `toml:"-"`
 	httpconfig.HTTPClientConfig
 
+	client *http.Client
+
 	// Locally cached clients
 	identity *gophercloud.ServiceClient
 	compute  *gophercloud.ServiceClient
@@ -153,7 +156,8 @@ func (o *OpenStack) Start(_ telegraf.Accumulator) error {
 		return err
 	}
 
-	provider.HTTPClient = *client
+	o.client = client
+	provider.HTTPClient = *o.client
 
 	// Authenticate to the endpoint
 	authOption := gophercloud.AuthOptions{
@@ -226,7 +230,11 @@ func (o *OpenStack) Start(_ telegraf.Accumulator) error {
 	return nil
 }
 
-func (o *OpenStack) Stop() {}
+func (o *OpenStack) Stop() {
+	if o.client != nil {
+		o.client.CloseIdleConnections()
+	}
+}
 
 // Gather gathers resources from the OpenStack API and accumulates metrics.  This
 // implements the Input interface.

plugins/inputs/prometheus/prometheus.go

@@ -588,6 +588,10 @@ func (p *Prometheus) Start(_ telegraf.Accumulator) error {
 func (p *Prometheus) Stop() {
 	p.cancel()
 	p.wg.Wait()
+
+	if p.client != nil {
+		p.client.CloseIdleConnections()
+	}
 }
 
 func init() {

plugins/inputs/vault/vault.go

@@ -70,6 +70,10 @@ func (n *Vault) Init() error {
 	return nil
 }
 
+func (n *Vault) Start(_ telegraf.Accumulator) error {
+	return nil
+}
+
 // Gather, collects metrics from Vault endpoint
 func (n *Vault) Gather(acc telegraf.Accumulator) error {
 	sysMetrics, err := n.loadJSON(n.URL + "/v1/sys/metrics")
@@ -80,6 +84,12 @@ func (n *Vault) Gather(acc telegraf.Accumulator) error {
 	return buildVaultMetrics(acc, sysMetrics)
 }
 
+func (n *Vault) Stop() {
+	if n.client != nil {
+		n.client.CloseIdleConnections()
+	}
+}
+
 func (n *Vault) loadJSON(url string) (*SysMetrics, error) {
 	req, err := http.NewRequest("GET", url, nil)
 	if err != nil {

plugins/outputs/cloudwatch/cloudwatch.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	_ "embed"
 	"math"
+	"net/http"
 	"sort"
 	"strings"
 	"time"
@@ -30,6 +31,7 @@ type CloudWatch struct {
 	Log                   telegraf.Logger `toml:"-"`
 	internalaws.CredentialConfig
 	httpconfig.HTTPClientConfig
+	client *http.Client
 }
 
 type statisticType int
@@ -170,14 +172,20 @@ func (c *CloudWatch) Connect() error {
 		return err
 	}
 
+	c.client = client
+
 	c.svc = cloudwatch.NewFromConfig(cfg, func(options *cloudwatch.Options) {
-		options.HTTPClient = client
+		options.HTTPClient = c.client
 	})
 
 	return nil
 }
 
 func (c *CloudWatch) Close() error {
+	if c.client != nil {
+		c.client.CloseIdleConnections()
+	}
+
 	return nil
 }
 

plugins/outputs/http/http.go

@@ -102,6 +102,10 @@ func (h *HTTP) Connect() error {
 }
 
 func (h *HTTP) Close() error {
+	if h.client != nil {
+		h.client.CloseIdleConnections()
+	}
+
 	return nil
 }
 

plugins/secretstores/http/http.go

@@ -11,6 +11,7 @@ import (
 	"io"
 	"net/http"
 	"strings"
+	"time"
 
 	"github.com/blues/jsonata-go"
 
@@ -23,6 +24,8 @@ import (
 //go:embed sample.conf
 var sampleConfig string
 
+const defaultIdleConnTimeoutMinutes = 5
+
 type HTTP struct {
 	URL                string            `toml:"url"`
 	Headers            map[string]string `toml:"headers"`
@@ -47,6 +50,12 @@ func (h *HTTP) SampleConfig() string {
 
 func (h *HTTP) Init() error {
 	ctx := context.Background()
+
+	// Prevent idle connections from hanging around forever on telegraf reload
+	if h.HTTPClientConfig.IdleConnTimeout == 0 {
+		h.HTTPClientConfig.IdleConnTimeout = config.Duration(defaultIdleConnTimeoutMinutes * time.Minute)
+	}
+
 	client, err := h.HTTPClientConfig.CreateClient(ctx, h.Log)
 	if err != nil {
 		return err