add proxy (influxdata#8915)

plugins/inputs/cloudwatch/README.md

@@ -41,6 +41,9 @@ API endpoint. In the following order the plugin will attempt to authenticate.
   ##   ex: endpoint_url = "http://localhost:8000"
   # endpoint_url = ""
 
+  ## Set http_proxy (telegraf uses the system wide proxy settings if it's is not set)
+  # http_proxy_url = "http://localhost:8888"
+
   # The minimum period for Cloudwatch metrics is 1 minute (60s). However not all
   # metrics are made available to the 1 minute period. Some are collected at
   # 3 minute, 5 minute, or larger intervals. See https://aws.amazon.com/cloudwatch/faqs/#monitoring.

plugins/inputs/cloudwatch/cloudwatch.go

@@ -18,6 +18,7 @@ import (
 	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/internal/limiter"
 	"github.com/influxdata/telegraf/metric"
+	"github.com/influxdata/telegraf/plugins/common/proxy"
 	"github.com/influxdata/telegraf/plugins/inputs"
 )
 
@@ -35,6 +36,8 @@ type CloudWatch struct {
 	StatisticInclude []string        `toml:"statistic_include"`
 	Timeout          config.Duration `toml:"timeout"`
 
+	proxy.HTTPProxy
+
 	Period         config.Duration `toml:"period"`
 	Delay          config.Duration `toml:"delay"`
 	Namespace      string          `toml:"namespace"`
@@ -107,6 +110,9 @@ func (c *CloudWatch) SampleConfig() string {
   ##   ex: endpoint_url = "http://localhost:8000"
   # endpoint_url = ""
 
+  ## Set http_proxy (telegraf uses the system wide proxy settings if it's is not set)
+  # http_proxy_url = "http://localhost:8888"
+
   # The minimum period for Cloudwatch metrics is 1 minute (60s). However not all
   # metrics are made available to the 1 minute period. Some are collected at
   # 3 minute, 5 minute, or larger intervals. See https://aws.amazon.com/cloudwatch/faqs/#monitoring.
@@ -188,7 +194,10 @@ func (c *CloudWatch) Gather(acc telegraf.Accumulator) error {
 	}
 
 	if c.client == nil {
-		c.initializeCloudWatch()
+		err := c.initializeCloudWatch()
+		if err != nil {
+			return err
+		}
 	}
 
 	filteredMetrics, err := getFilteredMetrics(c)
@@ -249,7 +258,7 @@ func (c *CloudWatch) Gather(acc telegraf.Accumulator) error {
 	return c.aggregateMetrics(acc, results)
 }
 
-func (c *CloudWatch) initializeCloudWatch() {
+func (c *CloudWatch) initializeCloudWatch() error {
 	credentialConfig := &internalaws.CredentialConfig{
 		Region:      c.Region,
 		AccessKey:   c.AccessKey,
@@ -262,11 +271,16 @@ func (c *CloudWatch) initializeCloudWatch() {
 	}
 	configProvider := credentialConfig.Credentials()
 
+	proxy, err := c.HTTPProxy.Proxy()
+	if err != nil {
+		return err
+	}
+
 	cfg := &aws.Config{
 		HTTPClient: &http.Client{
 			// use values from DefaultTransport
 			Transport: &http.Transport{
-				Proxy: http.ProxyFromEnvironment,
+				Proxy: proxy,
 				DialContext: (&net.Dialer{
 					Timeout:   30 * time.Second,
 					KeepAlive: 30 * time.Second,
@@ -283,6 +297,8 @@ func (c *CloudWatch) initializeCloudWatch() {
 
 	loglevel := aws.LogOff
 	c.client = cloudwatch.New(configProvider, cfg.WithLogLevel(loglevel))
+
+	return nil
 }
 
 type filteredMetric struct {

plugins/inputs/cloudwatch/cloudwatch_test.go

@@ -1,6 +1,7 @@
 package cloudwatch
 
 import (
+	"net/http"
 	"testing"
 	"time"
 
@@ -11,6 +12,7 @@ import (
 
 	"github.com/influxdata/telegraf/config"
 	"github.com/influxdata/telegraf/filter"
+	"github.com/influxdata/telegraf/plugins/common/proxy"
 	"github.com/influxdata/telegraf/testutil"
 )
 
@@ -333,3 +335,16 @@ func TestUpdateWindow(t *testing.T) {
 	assert.EqualValues(t, c.windowEnd, now.Add(-time.Duration(c.Delay)))
 	assert.EqualValues(t, c.windowStart, newStartTime)
 }
+
+func TestProxyFunction(t *testing.T) {
+	c := &CloudWatch{
+		HTTPProxy: proxy.HTTPProxy{HTTPProxyURL: "http://www.penguins.com"},
+	}
+
+	proxyFunction, err := c.HTTPProxy.Proxy()
+	require.NoError(t, err)
+
+	proxyResult, err := proxyFunction(&http.Request{})
+	require.NoError(t, err)
+	require.Equal(t, "www.penguins.com", proxyResult.Host)
+}