[confighttp] Add support for cookies (#10176)

#### Description
Add support for cookies in HTTP clients with `cookies::enabled`.

#### Link to tracking issue
Fixes #10175

#### Testing
Unit test

#### Documentation
Added to README

.chloggen/cookie_support.yaml

@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: confighttp
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add support for cookies in HTTP clients with `cookies::enabled`.
+
+# One or more tracking issues or pull requests related to the change
+issues: [10175]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: The method `confighttp.ToClient` will return a client with a `cookiejar.Jar` which will reuse cookies from server responses in subsequent requests.
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

config/confighttp/README.md

@@ -34,6 +34,8 @@ README](../configtls/README.md).
 - [`disable_keep_alives`](https://golang.org/pkg/net/http/#Transport)
 - [`http2_read_idle_timeout`](https://pkg.go.dev/golang.org/x/net/http2#Transport)
 - [`http2_ping_timeout`](https://pkg.go.dev/golang.org/x/net/http2#Transport)
+- [`cookies`](https://pkg.go.dev/net/http#CookieJar)
+  - [`enabled`] if enabled, the client will store cookies from server responses and reuse them in subsequent requests.
 
 Example:
 
@@ -51,6 +53,8 @@ exporter:
       test1: "value1"
       "test 2": "value 2"
     compression: zstd
+    cookies:
+      enabled: true
 ```
 
 ## Server Configuration

config/confighttp/confighttp.go

@@ -11,13 +11,15 @@ import (
 	"io"
 	"net"
 	"net/http"
+	"net/http/cookiejar"
 	"net/url"
 	"time"
 
 	"github.com/rs/cors"
 	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 	"go.opentelemetry.io/otel"
 	"golang.org/x/net/http2"
+	"golang.org/x/net/publicsuffix"
 
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/config/configauth"
@@ -104,6 +106,14 @@ type ClientConfig struct {
 	// HTTP2PingTimeout if there's no response to the ping within the configured value, the connection will be closed.
 	// If not set or set to 0, it defaults to 15s.
 	HTTP2PingTimeout time.Duration `mapstructure:"http2_ping_timeout"`
+	// Cookies configures the cookie management of the HTTP client.
+	Cookies *CookiesConfig `mapstructure:"cookies"`
+}
+
+// CookiesConfig defines the configuration of the HTTP client regarding cookies served by the server.
+type CookiesConfig struct {
+	// Enabled if true, cookies from HTTP responses will be reused in further HTTP requests with the same server.
+	Enabled bool `mapstructure:"enabled"`
 }
 
 // NewDefaultClientConfig returns ClientConfig type object with
@@ -232,9 +242,18 @@ func (hcs *ClientConfig) ToClient(ctx context.Context, host component.Host, sett
 		}
 	}
 
+	var jar http.CookieJar
+	if hcs.Cookies != nil && hcs.Cookies.Enabled {
+		jar, err = cookiejar.New(&cookiejar.Options{PublicSuffixList: publicsuffix.List})
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	return &http.Client{
 		Transport: clientTransport,
 		Timeout:   hcs.Timeout,
+		Jar:       jar,
 	}, nil
 }
 

config/confighttp/confighttp_test.go

@@ -83,6 +83,7 @@ func TestAllHTTPClientSettings(t *testing.T) {
 				IdleConnTimeout:      &idleConnTimeout,
 				Compression:          "",
 				DisableKeepAlives:    true,
+				Cookies:              &CookiesConfig{Enabled: true},
 				HTTP2ReadIdleTimeout: idleConnTimeout,
 				HTTP2PingTimeout:     http2PingTimeout,
 			},