Auth: Add Sigv4 auth option to datasources (#27552)

* create transport chain

* add frontend

* remove log

* inline field updates

* allow ARN, Credentials + Keys auth in frontend

* configure credentials

* add tests and refactor

* update frontend json field names

* fix tests

* fix comment

* add app config flag

* refactor tests

* add return field for tests

* add flag for UI display

* update comment

* move logic

* fix config

* pass config through props

* update docs

* pr feedback and add docs coverage

* shorten settings filename

* fix imports

* revert docs changes

* remove log line

* wrap up next as round tripper

* only propagate required config

* remove unused import

* remove ARN option and replace with default chain

* make ARN role assume as supplemental

* update docs

* refactor flow

* sign body when necessary

* remove unnecessary wrapper

* remove newline

* Apply suggestions from code review

* PR fixes

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

pkg/setting/setting.go

@@ -143,6 +143,7 @@ var (
 	AdminPassword    string
 	LoginCookieName  string
 	LoginMaxLifetime time.Duration
+	SigV4AuthEnabled bool
 
 	AnonymousEnabled bool
 	AnonymousOrgName string
@@ -280,6 +281,7 @@ type Cfg struct {
 	LoginMaxInactiveLifetime     time.Duration
 	LoginMaxLifetime             time.Duration
 	TokenRotationIntervalMinutes int
+	SigV4AuthEnabled             bool
 
 	// OAuth
 	OAuthCookieMaxAge int
@@ -990,6 +992,10 @@ func readAuthSettings(iniFile *ini.File, cfg *Cfg) (err error) {
 	cfg.OAuthCookieMaxAge = auth.Key("oauth_state_cookie_max_age").MustInt(600)
 	SignoutRedirectUrl = valueAsString(auth, "signout_redirect_url", "")
 
+	// SigV4
+	SigV4AuthEnabled = auth.Key("sigv4_auth_enabled").MustBool(false)
+	cfg.SigV4AuthEnabled = SigV4AuthEnabled
+
 	// SAML auth
 	cfg.SAMLEnabled = iniFile.Section("auth.saml").Key("enabled").MustBool(false)