cli: print oauth errors better, respect slow_down (#169164)

For diagnosing https://github.com/microsoft/vscode/issues/169066

cli/src/auth.rs

@@ -9,7 +9,9 @@ use crate::{
 	state::{LauncherPaths, PersistedState},
 	trace,
 	util::{
-		errors::{wrap, AnyError, RefreshTokenNotAvailableError, StatusError, WrappedError},
+		errors::{
+			wrap, AnyError, OAuthError, RefreshTokenNotAvailableError, StatusError, WrappedError,
+		},
 		input::prompt_options,
 	},
 	warning,
@@ -41,6 +43,12 @@ struct AuthenticationResponse {
 	expires_in: Option<i64>,
 }
 
+#[derive(Deserialize)]
+struct AuthenticationError {
+	error: String,
+	error_description: Option<String>,
+}
+
 #[derive(clap::ArgEnum, Serialize, Deserialize, Debug, Clone, Copy)]
 pub enum AuthProvider {
 	Microsoft,
@@ -480,12 +488,26 @@ impl Auth {
 			.send()
 			.await?;
 
-		if !response.status().is_success() {
-			return Err(StatusError::from_res(response).await?.into());
+		let status_code = response.status().as_u16();
+		let body = response.bytes().await?;
+		if let Ok(body) = serde_json::from_slice::<AuthenticationResponse>(&body) {
+			return Ok(StoredCredential::from_response(body, provider));
 		}
 
-		let body = response.json::<AuthenticationResponse>().await?;
-		Ok(StoredCredential::from_response(body, provider))
+		if let Ok(res) = serde_json::from_slice::<AuthenticationError>(&body) {
+			return Err(OAuthError {
+				error: res.error,
+				error_description: res.error_description,
+			}
+			.into());
+		}
+
+		return Err(StatusError {
+			body: String::from_utf8_lossy(&body).to_string(),
+			status_code,
+			url: provider.grant_uri().to_string(),
+		}
+		.into());
 	}
 
 	/// Implements the device code flow, returning the credentials upon success.
@@ -540,16 +562,21 @@ impl Auth {
 			};
 
 			let body = format!(
-                "client_id={}&grant_type=urn:ietf:params:oauth:grant-type:device_code&device_code={}",
-                provider.client_id(),
-                init_code_json.device_code
-            );
+					"client_id={}&grant_type=urn:ietf:params:oauth:grant-type:device_code&device_code={}",
+					provider.client_id(),
+					init_code_json.device_code
+			);
 
+			let mut interval_s = 5;
 			while Utc::now() < expires_at {
-				sleep(std::time::Duration::from_secs(5)).await;
+				sleep(std::time::Duration::from_secs(interval_s)).await;
 
 				match self.do_grant(provider, body.clone()).await {
 					Ok(creds) => return Ok(creds),
+					Err(AnyError::OAuthError(e)) if e.error == "slow_down" => {
+						interval_s += 5; // https://www.rfc-editor.org/rfc/rfc8628#section-3.5
+						trace!(self.log, "refresh poll failed, slowing down");
+					}
 					Err(e) => {
 						trace!(self.log, "refresh poll failed, retrying: {}", e);
 					}

cli/src/util/errors.rs

@@ -401,6 +401,23 @@ impl std::fmt::Display for MissingHomeDirectory {
 	}
 }
 
+#[derive(Debug)]
+pub struct OAuthError {
+	pub error: String,
+	pub error_description: Option<String>,
+}
+
+impl std::fmt::Display for OAuthError {
+	fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+		write!(
+			f,
+			"Error getting authorization: {} {}",
+			self.error,
+			self.error_description.as_deref().unwrap_or("")
+		)
+	}
+}
+
 #[derive(Debug)]
 pub struct CommandFailed {
 	pub output: std::process::Output,
@@ -487,7 +504,8 @@ makeAnyError!(
 	UpdatesNotConfigured,
 	CorruptDownload,
 	MissingHomeDirectory,
-	CommandFailed
+	CommandFailed,
+	OAuthError
 );
 
 impl From<reqwest::Error> for AnyError {