Line data    Source code

       1              : use crate::tenant_shard::ObservedState;
       2              : use pageserver_api::shard::TenantShardId;
       3              : use serde::{Deserialize, Serialize};
       4              : use std::collections::HashMap;
       5              : use std::error::Error as _;
       6              : use std::time::Duration;
       7              : use tokio_util::sync::CancellationToken;
       8              : 
       9              : use http_utils::error::HttpErrorBody;
      10              : use hyper::Uri;
      11              : use reqwest::{StatusCode, Url};
      12              : use utils::backoff;
      13              : 
      14              : #[derive(Debug, Clone)]
      15              : pub(crate) struct PeerClient {
      16              :     uri: Uri,
      17              :     jwt: Option<String>,
      18              :     client: reqwest::Client,
      19              : }
      20              : 
      21              : #[derive(thiserror::Error, Debug)]
      22              : pub(crate) enum StorageControllerPeerError {
      23              :     #[error(
      24              :         "failed to deserialize error response with status code {0} at {1}: {2}{}",
      25            0 :         .2.source().map(|e| format!(": {e}")).unwrap_or_default()
      26              :     )]
      27              :     DeserializationError(StatusCode, Url, reqwest::Error),
      28              :     #[error("storage controller peer API error ({0}): {1}")]
      29              :     ApiError(StatusCode, String),
      30            0 :     #[error("failed to send HTTP request: {0}{}", .0.source().map(|e| format!(": {e}")).unwrap_or_default())]
      31              :     SendError(reqwest::Error),
      32              :     #[error("Cancelled")]
      33              :     Cancelled,
      34              : }
      35              : 
      36              : pub(crate) type Result<T> = std::result::Result<T, StorageControllerPeerError>;
      37              : 
      38              : pub(crate) trait ResponseErrorMessageExt: Sized {
      39              :     fn error_from_body(self) -> impl std::future::Future<Output = Result<Self>> + Send;
      40              : }
      41              : 
      42              : impl ResponseErrorMessageExt for reqwest::Response {
      43            0 :     async fn error_from_body(self) -> Result<Self> {
      44            0 :         let status = self.status();
      45            0 :         if !(status.is_client_error() || status.is_server_error()) {
      46            0 :             return Ok(self);
      47            0 :         }
      48            0 : 
      49            0 :         let url = self.url().to_owned();
      50            0 :         Err(match self.json::<HttpErrorBody>().await {
      51            0 :             Ok(HttpErrorBody { msg }) => StorageControllerPeerError::ApiError(status, msg),
      52            0 :             Err(err) => StorageControllerPeerError::DeserializationError(status, url, err),
      53              :         })
      54            0 :     }
      55              : }
      56              : 
      57            0 : #[derive(Serialize, Deserialize, Debug, Default)]
      58              : pub(crate) struct GlobalObservedState(pub(crate) HashMap<TenantShardId, ObservedState>);
      59              : 
      60              : impl PeerClient {
      61            0 :     pub(crate) fn new(uri: Uri, jwt: Option<String>) -> Self {
      62            0 :         Self {
      63            0 :             uri,
      64            0 :             jwt,
      65            0 :             client: reqwest::Client::new(),
      66            0 :         }
      67            0 :     }
      68              : 
      69            0 :     async fn request_step_down(&self) -> Result<GlobalObservedState> {
      70            0 :         let step_down_path = format!("{}control/v1/step_down", self.uri);
      71            0 :         let req = self.client.put(step_down_path);
      72            0 :         let req = if let Some(jwt) = &self.jwt {
      73            0 :             req.header(reqwest::header::AUTHORIZATION, format!("Bearer {jwt}"))
      74              :         } else {
      75            0 :             req
      76              :         };
      77              : 
      78            0 :         let req = req.timeout(Duration::from_secs(2));
      79              : 
      80            0 :         let res = req
      81            0 :             .send()
      82            0 :             .await
      83            0 :             .map_err(StorageControllerPeerError::SendError)?;
      84            0 :         let response = res.error_from_body().await?;
      85              : 
      86            0 :         let status = response.status();
      87            0 :         let url = response.url().to_owned();
      88            0 : 
      89            0 :         response
      90            0 :             .json()
      91            0 :             .await
      92            0 :             .map_err(|err| StorageControllerPeerError::DeserializationError(status, url, err))
      93            0 :     }
      94              : 
      95              :     /// Request the peer to step down and return its current observed state
      96              :     /// All errors are retried with exponential backoff for a maximum of 4 attempts.
      97              :     /// Assuming all retries are performed, the function times out after roughly 4 seconds.
      98            0 :     pub(crate) async fn step_down(
      99            0 :         &self,
     100            0 :         cancel: &CancellationToken,
     101            0 :     ) -> Result<GlobalObservedState> {
     102            0 :         backoff::retry(
     103            0 :             || self.request_step_down(),
     104            0 :             |_e| false,
     105            0 :             2,
     106            0 :             4,
     107            0 :             "Send step down request",
     108            0 :             cancel,
     109            0 :         )
     110            0 :         .await
     111            0 :         .ok_or_else(|| StorageControllerPeerError::Cancelled)
     112            0 :         .and_then(|x| x)
     113            0 :     }
     114              : }