Line data Source code
1 : //! This module provides a wrapper around a real RemoteStorage implementation that
2 : //! causes the first N attempts at each upload or download operatio to fail. For
3 : //! testing purposes.
4 : use bytes::Bytes;
5 : use futures::stream::Stream;
6 : use futures::StreamExt;
7 : use std::collections::HashMap;
8 : use std::num::NonZeroU32;
9 : use std::sync::Mutex;
10 : use std::time::SystemTime;
11 : use std::{collections::hash_map::Entry, sync::Arc};
12 : use tokio_util::sync::CancellationToken;
13 :
14 : use crate::{
15 : Download, DownloadError, GenericRemoteStorage, Listing, ListingMode, RemotePath, RemoteStorage,
16 : StorageMetadata, TimeTravelError,
17 : };
18 :
19 : pub struct UnreliableWrapper {
20 : inner: GenericRemoteStorage<Arc<VoidStorage>>,
21 :
22 : // This many attempts of each operation will fail, then we let it succeed.
23 : attempts_to_fail: u64,
24 :
25 : // Tracks how many failed attempts of each operation has been made.
26 : attempts: Mutex<HashMap<RemoteOp, u64>>,
27 : }
28 :
29 : /// Used to identify retries of different unique operation.
30 : #[derive(Debug, Hash, Eq, PartialEq)]
31 : enum RemoteOp {
32 : ListPrefixes(Option<RemotePath>),
33 : HeadObject(RemotePath),
34 : Upload(RemotePath),
35 : Download(RemotePath),
36 : Delete(RemotePath),
37 : DeleteObjects(Vec<RemotePath>),
38 : TimeTravelRecover(Option<RemotePath>),
39 : }
40 :
41 : impl UnreliableWrapper {
42 2 : pub fn new(inner: crate::GenericRemoteStorage, attempts_to_fail: u64) -> Self {
43 2 : assert!(attempts_to_fail > 0);
44 2 : let inner = match inner {
45 0 : GenericRemoteStorage::AwsS3(s) => GenericRemoteStorage::AwsS3(s),
46 0 : GenericRemoteStorage::AzureBlob(s) => GenericRemoteStorage::AzureBlob(s),
47 2 : GenericRemoteStorage::LocalFs(s) => GenericRemoteStorage::LocalFs(s),
48 : // We could also make this a no-op, as in, extract the inner of the passed generic remote storage
49 0 : GenericRemoteStorage::Unreliable(_s) => {
50 0 : panic!("Can't wrap unreliable wrapper unreliably")
51 : }
52 : };
53 2 : UnreliableWrapper {
54 2 : inner,
55 2 : attempts_to_fail,
56 2 : attempts: Mutex::new(HashMap::new()),
57 2 : }
58 2 : }
59 :
60 : ///
61 : /// Common functionality for all operations.
62 : ///
63 : /// On the first attempts of this operation, return an error. After 'attempts_to_fail'
64 : /// attempts, let the operation go ahead, and clear the counter.
65 : ///
66 24 : fn attempt(&self, op: RemoteOp) -> anyhow::Result<u64> {
67 24 : let mut attempts = self.attempts.lock().unwrap();
68 24 :
69 24 : match attempts.entry(op) {
70 12 : Entry::Occupied(mut e) => {
71 12 : let attempts_before_this = {
72 12 : let p = e.get_mut();
73 12 : *p += 1;
74 12 : *p
75 12 : };
76 12 :
77 12 : if attempts_before_this >= self.attempts_to_fail {
78 : // let it succeed
79 12 : e.remove();
80 12 : Ok(attempts_before_this)
81 : } else {
82 0 : let error =
83 0 : anyhow::anyhow!("simulated failure of remote operation {:?}", e.key());
84 0 : Err(error)
85 : }
86 : }
87 12 : Entry::Vacant(e) => {
88 12 : let error = anyhow::anyhow!("simulated failure of remote operation {:?}", e.key());
89 12 : e.insert(1);
90 12 : Err(error)
91 : }
92 : }
93 24 : }
94 :
95 0 : async fn delete_inner(
96 0 : &self,
97 0 : path: &RemotePath,
98 0 : attempt: bool,
99 0 : cancel: &CancellationToken,
100 0 : ) -> anyhow::Result<()> {
101 0 : if attempt {
102 0 : self.attempt(RemoteOp::Delete(path.clone()))?;
103 0 : }
104 0 : self.inner.delete(path, cancel).await
105 0 : }
106 : }
107 :
108 : // We never construct this, so the type is not important, just has to not be UnreliableWrapper and impl RemoteStorage.
109 : type VoidStorage = crate::LocalFs;
110 :
111 : impl RemoteStorage for UnreliableWrapper {
112 0 : fn list_streaming(
113 0 : &self,
114 0 : prefix: Option<&RemotePath>,
115 0 : mode: ListingMode,
116 0 : max_keys: Option<NonZeroU32>,
117 0 : cancel: &CancellationToken,
118 0 : ) -> impl Stream<Item = Result<Listing, DownloadError>> + Send {
119 0 : async_stream::stream! {
120 0 : self.attempt(RemoteOp::ListPrefixes(prefix.cloned()))
121 0 : .map_err(DownloadError::Other)?;
122 0 : let mut stream = self.inner
123 0 : .list_streaming(prefix, mode, max_keys, cancel);
124 0 : while let Some(item) = stream.next().await {
125 0 : yield item;
126 0 : }
127 0 : }
128 0 : }
129 0 : async fn list(
130 0 : &self,
131 0 : prefix: Option<&RemotePath>,
132 0 : mode: ListingMode,
133 0 : max_keys: Option<NonZeroU32>,
134 0 : cancel: &CancellationToken,
135 0 : ) -> Result<Listing, DownloadError> {
136 0 : self.attempt(RemoteOp::ListPrefixes(prefix.cloned()))
137 0 : .map_err(DownloadError::Other)?;
138 0 : self.inner.list(prefix, mode, max_keys, cancel).await
139 0 : }
140 :
141 0 : async fn head_object(
142 0 : &self,
143 0 : key: &RemotePath,
144 0 : cancel: &CancellationToken,
145 0 : ) -> Result<crate::ListingObject, DownloadError> {
146 0 : self.attempt(RemoteOp::HeadObject(key.clone()))
147 0 : .map_err(DownloadError::Other)?;
148 0 : self.inner.head_object(key, cancel).await
149 0 : }
150 :
151 24 : async fn upload(
152 24 : &self,
153 24 : data: impl Stream<Item = std::io::Result<Bytes>> + Send + Sync + 'static,
154 24 : // S3 PUT request requires the content length to be specified,
155 24 : // otherwise it starts to fail with the concurrent connection count increasing.
156 24 : data_size_bytes: usize,
157 24 : to: &RemotePath,
158 24 : metadata: Option<StorageMetadata>,
159 24 : cancel: &CancellationToken,
160 24 : ) -> anyhow::Result<()> {
161 24 : self.attempt(RemoteOp::Upload(to.clone()))?;
162 12 : self.inner
163 12 : .upload(data, data_size_bytes, to, metadata, cancel)
164 38 : .await
165 24 : }
166 :
167 0 : async fn download(
168 0 : &self,
169 0 : from: &RemotePath,
170 0 : cancel: &CancellationToken,
171 0 : ) -> Result<Download, DownloadError> {
172 0 : self.attempt(RemoteOp::Download(from.clone()))
173 0 : .map_err(DownloadError::Other)?;
174 0 : self.inner.download(from, cancel).await
175 0 : }
176 :
177 0 : async fn download_byte_range(
178 0 : &self,
179 0 : from: &RemotePath,
180 0 : start_inclusive: u64,
181 0 : end_exclusive: Option<u64>,
182 0 : cancel: &CancellationToken,
183 0 : ) -> Result<Download, DownloadError> {
184 0 : // Note: We treat any download_byte_range as an "attempt" of the same
185 0 : // operation. We don't pay attention to the ranges. That's good enough
186 0 : // for now.
187 0 : self.attempt(RemoteOp::Download(from.clone()))
188 0 : .map_err(DownloadError::Other)?;
189 0 : self.inner
190 0 : .download_byte_range(from, start_inclusive, end_exclusive, cancel)
191 0 : .await
192 0 : }
193 :
194 0 : async fn delete(&self, path: &RemotePath, cancel: &CancellationToken) -> anyhow::Result<()> {
195 0 : self.delete_inner(path, true, cancel).await
196 0 : }
197 :
198 0 : async fn delete_objects<'a>(
199 0 : &self,
200 0 : paths: &'a [RemotePath],
201 0 : cancel: &CancellationToken,
202 0 : ) -> anyhow::Result<()> {
203 0 : self.attempt(RemoteOp::DeleteObjects(paths.to_vec()))?;
204 0 : let mut error_counter = 0;
205 0 : for path in paths {
206 : // Dont record attempt because it was already recorded above
207 0 : if (self.delete_inner(path, false, cancel).await).is_err() {
208 0 : error_counter += 1;
209 0 : }
210 : }
211 0 : if error_counter > 0 {
212 0 : return Err(anyhow::anyhow!(
213 0 : "failed to delete {} objects",
214 0 : error_counter
215 0 : ));
216 0 : }
217 0 : Ok(())
218 0 : }
219 :
220 0 : async fn copy(
221 0 : &self,
222 0 : from: &RemotePath,
223 0 : to: &RemotePath,
224 0 : cancel: &CancellationToken,
225 0 : ) -> anyhow::Result<()> {
226 0 : // copy is equivalent to download + upload
227 0 : self.attempt(RemoteOp::Download(from.clone()))?;
228 0 : self.attempt(RemoteOp::Upload(to.clone()))?;
229 0 : self.inner.copy_object(from, to, cancel).await
230 0 : }
231 :
232 0 : async fn time_travel_recover(
233 0 : &self,
234 0 : prefix: Option<&RemotePath>,
235 0 : timestamp: SystemTime,
236 0 : done_if_after: SystemTime,
237 0 : cancel: &CancellationToken,
238 0 : ) -> Result<(), TimeTravelError> {
239 0 : self.attempt(RemoteOp::TimeTravelRecover(prefix.map(|p| p.to_owned())))
240 0 : .map_err(TimeTravelError::Other)?;
241 0 : self.inner
242 0 : .time_travel_recover(prefix, timestamp, done_if_after, cancel)
243 0 : .await
244 0 : }
245 : }
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