remote/http: add an optional request body

CHANGELOG.md

@@ -35,6 +35,8 @@ Main (unreleased)
 - Added links between compatible components in the documentation to make it
   easier to discover them. (@thampiotr)
 
+- The `remote.http` component can optionally define a request body. (@tpaschalis)
+
 ### Bugfixes
 
 - Update `pyroscope.ebpf` to fix a logical bug causing to profile to many kthreads instead of regular processes https://github.com/grafana/pyroscope/pull/2778 (@korniltsev)

component/remote/http/http.go

@@ -41,6 +41,7 @@ type Arguments struct {
 
 	Method  string            `river:"method,attr,optional"`
 	Headers map[string]string `river:"headers,attr,optional"`
+	Body    string            `river:"body,attr,optional"`
 
 	Client common_config.HTTPClientConfig `river:"client,block,optional"`
 }
@@ -193,7 +194,12 @@ func (c *Component) pollError() error {
 	ctx, cancel := context.WithTimeout(context.Background(), c.args.PollTimeout)
 	defer cancel()
 
-	req, err := http.NewRequest(c.args.Method, c.args.URL, nil)
+	var body io.Reader
+	if c.args.Body != "" {
+		body = strings.NewReader(c.args.Body)
+	}
+
+	req, err := http.NewRequest(c.args.Method, c.args.URL, body)
 	if err != nil {
 		level.Error(c.log).Log("msg", "failed to build request", "err", err)
 		return fmt.Errorf("building request: %w", err)

component/remote/http/http_test.go

@@ -3,6 +3,7 @@ package http_test
 import (
 	"context"
 	"fmt"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"sync"
@@ -27,6 +28,9 @@ func Test(t *testing.T) {
 	defer srv.Close()
 
 	handler.SetHandler(func(w http.ResponseWriter, r *http.Request) {
+		b, err := io.ReadAll(r.Body)
+		require.NoError(t, err)
+		require.Equal(t, string(b), "hello there!")
 		fmt.Fprintln(w, "Hello, world!")
 	})
 
@@ -40,10 +44,11 @@ func Test(t *testing.T) {
             "x-custom" = "value",
 			"User-Agent" = "custom_useragent",
         }
+		body = "%s"
 
 		poll_frequency = "50ms" 
 		poll_timeout   = "25ms" 
-	`, srv.URL, http.MethodPut)
+	`, srv.URL, http.MethodPut, "hello there!")
 	var args http_component.Arguments
 	require.NoError(t, river.Unmarshal([]byte(cfg), &args))
 

docs/sources/flow/reference/components/remote.http.md

@@ -37,6 +37,7 @@ Name | Type | Description | Default | Required
 `url` | `string` | URL to poll. | | yes
 `method` | `string` | Define HTTP method for the request | `"GET"` | no
 `headers` | `map(string)` | Custom headers for the request. | `{}` | no
+`body`    | `string`      | The request body. | `""` | no
 `poll_frequency` | `duration` | Frequency to poll the URL. | `"1m"` | no
 `poll_timeout` | `duration` | Timeout when polling the URL. | `"10s"` | no
 `is_secret` | `bool` | Whether the response body should be treated as a secret. | false | no