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