feat: support aws managed service for prometheus

Aws prometheus needs aws signature support.

plugins/outputs/http/README.md

@@ -68,6 +68,27 @@ batch format by default.
   ## Maximum amount of time before idle connection is closed.
   ## Zero means no limit.
   # idle_conn_timeout = 0
+
+  ## Amazon Region
+  #region = "us-east-1"
+
+  ## Amazon Credentials
+  ## Credentials are loaded in the following order
+  ## 1) Web identity provider credentials via STS if role_arn and web_identity_token_file are specified
+  ## 2) Assumed credentials via STS if role_arn is specified
+  ## 3) explicit credentials from 'access_key' and 'secret_key'
+  ## 4) shared profile from 'profile'
+  ## 5) environment variables
+  ## 6) shared credentials file
+  ## 7) EC2 Instance Profile
+  #access_key = ""
+  #secret_key = ""
+  #token = ""
+  #role_arn = ""
+  #web_identity_token_file = ""
+  #role_session_name = ""
+  #profile = ""
+  #shared_credential_file = ""
 ```
 
 ### Optional Cookie Authentication Settings

plugins/outputs/http/http.go

@@ -4,12 +4,17 @@ import (
 	"bufio"
 	"bytes"
 	"context"
+	"crypto/sha256"
 	"fmt"
 	"io"
 	"net/http"
 	"strings"
+	"time"
 
+	awsV2 "github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/aws/aws-sdk-go-v2/aws/signer/v4"
 	"github.com/influxdata/telegraf"
+	internalaws "github.com/influxdata/telegraf/config/aws"
 	"github.com/influxdata/telegraf/internal"
 	httpconfig "github.com/influxdata/telegraf/plugins/common/http"
 	"github.com/influxdata/telegraf/plugins/outputs"
@@ -81,6 +86,27 @@ var sampleConfig = `
   ## Maximum amount of time before idle connection is closed.
   ## Zero means no limit.
   # idle_conn_timeout = 0
+
+  ## Amazon Region
+  #region = "us-east-1"
+
+  ## Amazon Credentials
+  ## Credentials are loaded in the following order
+  ## 1) Web identity provider credentials via STS if role_arn and web_identity_token_file are specified
+  ## 2) Assumed credentials via STS if role_arn is specified
+  ## 3) explicit credentials from 'access_key' and 'secret_key'
+  ## 4) shared profile from 'profile'
+  ## 5) environment variables
+  ## 6) shared credentials file
+  ## 7) EC2 Instance Profile
+  #access_key = ""
+  #secret_key = ""
+  #token = ""
+  #role_arn = ""
+  #web_identity_token_file = ""
+  #role_session_name = ""
+  #profile = ""
+  #shared_credential_file = ""
 `
 
 const (
@@ -97,18 +123,29 @@ type HTTP struct {
 	Headers         map[string]string `toml:"headers"`
 	ContentEncoding string            `toml:"content_encoding"`
 	UseBatchFormat  bool              `toml:"use_batch_format"`
+	AwsService      string            `toml:"aws_service"`
 	httpconfig.HTTPClientConfig
 	Log telegraf.Logger `toml:"-"`
 
 	client     *http.Client
 	serializer serializers.Serializer
+
+	awsCfg *awsV2.Config
+	internalaws.CredentialConfig
 }
 
 func (h *HTTP) SetSerializer(serializer serializers.Serializer) {
 	h.serializer = serializer
 }
 
 func (h *HTTP) Connect() error {
+	if h.AwsService != "" {
+		cfg, err := h.CredentialConfig.Credentials()
+		if err == nil {
+			h.awsCfg = &cfg
+		}
+	}
+
 	if h.Method == "" {
 		h.Method = http.MethodPost
 	}
@@ -180,11 +217,43 @@ func (h *HTTP) writeMetric(reqBody []byte) error {
 		reqBodyBuffer = rc
 	}
 
+	var payloadHash *string
+	if h.awsCfg != nil {
+		// We need a local copy of the full buffer, the signature scheme requires a sha256 of the request body.
+		buf := new(bytes.Buffer)
+		_, err = io.Copy(buf, reqBodyBuffer)
+		if err != nil {
+			return err
+		}
+
+		sum := sha256.Sum256(buf.Bytes())
+		reqBodyBuffer = buf
+
+		// sha256 is hex encoded
+		hash := fmt.Sprintf("%x", sum)
+		payloadHash = &hash
+	}
+
 	req, err := http.NewRequest(h.Method, h.URL, reqBodyBuffer)
 	if err != nil {
 		return err
 	}
 
+	if h.awsCfg != nil {
+		signer := v4.NewSigner()
+		ctx := context.Background()
+
+		credentials, err := h.awsCfg.Credentials.Retrieve(ctx)
+		if err != nil {
+			return err
+		}
+
+		err = signer.SignHTTP(ctx, credentials, req, *payloadHash, h.AwsService, h.Region, time.Now().UTC())
+		if err != nil {
+			return err
+		}
+	}
+
 	if h.Username != "" || h.Password != "" {
 		req.SetBasicAuth(h.Username, h.Password)
 	}

plugins/outputs/http/http_test.go

@@ -13,6 +13,7 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/influxdata/telegraf"
+	internalaws "github.com/influxdata/telegraf/config/aws"
 	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/metric"
 	httpconfig "github.com/influxdata/telegraf/plugins/common/http"
@@ -516,3 +517,53 @@ func TestBatchedUnbatched(t *testing.T) {
 		})
 	}
 }
+
+func TestAwsCredentials(t *testing.T) {
+	ts := httptest.NewServer(http.NotFoundHandler())
+	defer ts.Close()
+
+	u, err := url.Parse(fmt.Sprintf("http://%s", ts.Listener.Addr().String()))
+	require.NoError(t, err)
+
+	tests := []struct {
+		name         string
+		plugin       *HTTP
+		tokenHandler TestHandlerFunc
+		handler      TestHandlerFunc
+	}{
+		{
+			name: "simple credentials",
+			plugin: &HTTP{
+				URL:        u.String(),
+				AwsService: "aps",
+				CredentialConfig: internalaws.CredentialConfig{
+					Region:    "us-east-1",
+					AccessKey: "dummy",
+					SecretKey: "dummy",
+				},
+			},
+			handler: func(t *testing.T, w http.ResponseWriter, r *http.Request) {
+				require.Contains(t, r.Header["Authorization"][0], "AWS4-HMAC-SHA256")
+				require.Contains(t, r.Header["Authorization"][0], "=dummy/")
+				require.Contains(t, r.Header["Authorization"][0], "/us-east-1/")
+				w.WriteHeader(http.StatusOK)
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ts.Config.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				tt.handler(t, w, r)
+			})
+
+			serializer := influx.NewSerializer()
+			tt.plugin.SetSerializer(serializer)
+			err = tt.plugin.Connect()
+			require.NoError(t, err)
+
+			err = tt.plugin.Write([]telegraf.Metric{getMetric()})
+			require.NoError(t, err)
+		})
+	}
+}