opendal/services/hdfs/
backend.rs

1// Licensed to the Apache Software Foundation (ASF) under one
2// or more contributor license agreements.  See the NOTICE file
3// distributed with this work for additional information
4// regarding copyright ownership.  The ASF licenses this file
5// to you under the Apache License, Version 2.0 (the
6// "License"); you may not use this file except in compliance
7// with the License.  You may obtain a copy of the License at
8//
9//   http://www.apache.org/licenses/LICENSE-2.0
10//
11// Unless required by applicable law or agreed to in writing,
12// software distributed under the License is distributed on an
13// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14// KIND, either express or implied.  See the License for the
15// specific language governing permissions and limitations
16// under the License.
17
18use std::fmt::Debug;
19use std::fmt::Formatter;
20use std::io;
21use std::io::SeekFrom;
22use std::path::PathBuf;
23use std::sync::Arc;
24
25use log::debug;
26
27use super::delete::HdfsDeleter;
28use super::lister::HdfsLister;
29use super::reader::HdfsReader;
30use super::writer::HdfsWriter;
31use crate::raw::*;
32use crate::services::HdfsConfig;
33use crate::*;
34
35impl Configurator for HdfsConfig {
36    type Builder = HdfsBuilder;
37    fn into_builder(self) -> Self::Builder {
38        HdfsBuilder { config: self }
39    }
40}
41
42#[doc = include_str!("docs.md")]
43#[derive(Default)]
44pub struct HdfsBuilder {
45    config: HdfsConfig,
46}
47
48impl Debug for HdfsBuilder {
49    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
50        f.debug_struct("HdfsBuilder")
51            .field("config", &self.config)
52            .finish()
53    }
54}
55
56impl HdfsBuilder {
57    /// Set root of this backend.
58    ///
59    /// All operations will happen under this root.
60    pub fn root(mut self, root: &str) -> Self {
61        self.config.root = if root.is_empty() {
62            None
63        } else {
64            Some(root.to_string())
65        };
66
67        self
68    }
69
70    /// Set name_node of this backend.
71    ///
72    /// Valid format including:
73    ///
74    /// - `default`: using the default setting based on hadoop config.
75    /// - `hdfs://127.0.0.1:9000`: connect to hdfs cluster.
76    pub fn name_node(mut self, name_node: &str) -> Self {
77        if !name_node.is_empty() {
78            // Trim trailing `/` so that we can accept `http://127.0.0.1:9000/`
79            self.config.name_node = Some(name_node.trim_end_matches('/').to_string())
80        }
81
82        self
83    }
84
85    /// Set kerberos_ticket_cache_path of this backend
86    ///
87    /// This should be configured when kerberos is enabled.
88    pub fn kerberos_ticket_cache_path(mut self, kerberos_ticket_cache_path: &str) -> Self {
89        if !kerberos_ticket_cache_path.is_empty() {
90            self.config.kerberos_ticket_cache_path = Some(kerberos_ticket_cache_path.to_string())
91        }
92        self
93    }
94
95    /// Set user of this backend
96    pub fn user(mut self, user: &str) -> Self {
97        if !user.is_empty() {
98            self.config.user = Some(user.to_string())
99        }
100        self
101    }
102
103    /// Enable append capacity of this backend.
104    ///
105    /// This should be disabled when HDFS runs in non-distributed mode.
106    pub fn enable_append(mut self, enable_append: bool) -> Self {
107        self.config.enable_append = enable_append;
108        self
109    }
110
111    /// Set temp dir for atomic write.
112    ///
113    /// # Notes
114    ///
115    /// - When append is enabled, we will not use atomic write
116    ///   to avoid data loss and performance issue.
117    pub fn atomic_write_dir(mut self, dir: &str) -> Self {
118        self.config.atomic_write_dir = if dir.is_empty() {
119            None
120        } else {
121            Some(String::from(dir))
122        };
123        self
124    }
125}
126
127impl Builder for HdfsBuilder {
128    const SCHEME: Scheme = Scheme::Hdfs;
129    type Config = HdfsConfig;
130
131    fn build(self) -> Result<impl Access> {
132        debug!("backend build started: {:?}", &self);
133
134        let name_node = match &self.config.name_node {
135            Some(v) => v,
136            None => {
137                return Err(Error::new(ErrorKind::ConfigInvalid, "name node is empty")
138                    .with_context("service", Scheme::Hdfs))
139            }
140        };
141
142        let root = normalize_root(&self.config.root.unwrap_or_default());
143        debug!("backend use root {root}");
144
145        let mut builder = hdrs::ClientBuilder::new(name_node);
146        if let Some(ticket_cache_path) = &self.config.kerberos_ticket_cache_path {
147            builder = builder.with_kerberos_ticket_cache_path(ticket_cache_path.as_str());
148        }
149        if let Some(user) = &self.config.user {
150            builder = builder.with_user(user.as_str());
151        }
152
153        let client = builder.connect().map_err(new_std_io_error)?;
154
155        // Create root dir if not exist.
156        if let Err(e) = client.metadata(&root) {
157            if e.kind() == io::ErrorKind::NotFound {
158                debug!("root {root} is not exist, creating now");
159
160                client.create_dir(&root).map_err(new_std_io_error)?
161            }
162        }
163
164        let atomic_write_dir = self.config.atomic_write_dir;
165
166        // If atomic write dir is not exist, we must create it.
167        if let Some(d) = &atomic_write_dir {
168            if let Err(e) = client.metadata(d) {
169                if e.kind() == io::ErrorKind::NotFound {
170                    client.create_dir(d).map_err(new_std_io_error)?
171                }
172            }
173        }
174
175        Ok(HdfsBackend {
176            info: {
177                let am = AccessorInfo::default();
178                am.set_scheme(Scheme::Hdfs)
179                    .set_root(&root)
180                    .set_native_capability(Capability {
181                        stat: true,
182
183                        read: true,
184
185                        write: true,
186                        write_can_append: self.config.enable_append,
187
188                        create_dir: true,
189                        delete: true,
190
191                        list: true,
192
193                        rename: true,
194
195                        shared: true,
196
197                        ..Default::default()
198                    });
199
200                am.into()
201            },
202            root,
203            atomic_write_dir,
204            client: Arc::new(client),
205        })
206    }
207}
208
209/// Backend for hdfs services.
210#[derive(Debug, Clone)]
211pub struct HdfsBackend {
212    pub info: Arc<AccessorInfo>,
213    pub root: String,
214    atomic_write_dir: Option<String>,
215    pub client: Arc<hdrs::Client>,
216}
217
218/// hdrs::Client is thread-safe.
219unsafe impl Send for HdfsBackend {}
220unsafe impl Sync for HdfsBackend {}
221
222impl Access for HdfsBackend {
223    type Reader = HdfsReader<hdrs::AsyncFile>;
224    type Writer = HdfsWriter<hdrs::AsyncFile>;
225    type Lister = Option<HdfsLister>;
226    type Deleter = oio::OneShotDeleter<HdfsDeleter>;
227
228    fn info(&self) -> Arc<AccessorInfo> {
229        self.info.clone()
230    }
231
232    async fn create_dir(&self, path: &str, _: OpCreateDir) -> Result<RpCreateDir> {
233        let p = build_rooted_abs_path(&self.root, path);
234
235        self.client.create_dir(&p).map_err(new_std_io_error)?;
236
237        Ok(RpCreateDir::default())
238    }
239
240    async fn stat(&self, path: &str, _: OpStat) -> Result<RpStat> {
241        let p = build_rooted_abs_path(&self.root, path);
242
243        let meta = self.client.metadata(&p).map_err(new_std_io_error)?;
244
245        let mode = if meta.is_dir() {
246            EntryMode::DIR
247        } else if meta.is_file() {
248            EntryMode::FILE
249        } else {
250            EntryMode::Unknown
251        };
252        let mut m = Metadata::new(mode);
253        m.set_content_length(meta.len());
254        m.set_last_modified(meta.modified().into());
255
256        Ok(RpStat::new(m))
257    }
258
259    async fn read(&self, path: &str, args: OpRead) -> Result<(RpRead, Self::Reader)> {
260        let p = build_rooted_abs_path(&self.root, path);
261
262        let client = self.client.clone();
263        let mut f = client
264            .open_file()
265            .read(true)
266            .async_open(&p)
267            .await
268            .map_err(new_std_io_error)?;
269
270        if args.range().offset() != 0 {
271            use futures::AsyncSeekExt;
272
273            f.seek(SeekFrom::Start(args.range().offset()))
274                .await
275                .map_err(new_std_io_error)?;
276        }
277
278        Ok((
279            RpRead::new(),
280            HdfsReader::new(f, args.range().size().unwrap_or(u64::MAX) as _),
281        ))
282    }
283
284    async fn write(&self, path: &str, op: OpWrite) -> Result<(RpWrite, Self::Writer)> {
285        let target_path = build_rooted_abs_path(&self.root, path);
286        let mut initial_size = 0;
287        let target_exists = match self.client.metadata(&target_path) {
288            Ok(meta) => {
289                initial_size = meta.len();
290                true
291            }
292            Err(err) => {
293                if err.kind() != io::ErrorKind::NotFound {
294                    return Err(new_std_io_error(err));
295                }
296                false
297            }
298        };
299
300        let should_append = op.append() && target_exists;
301        let tmp_path = self.atomic_write_dir.as_ref().and_then(|atomic_write_dir| {
302            // If the target file exists, we should append to the end of it directly.
303            (!should_append).then_some(build_rooted_abs_path(
304                atomic_write_dir,
305                &build_tmp_path_of(path),
306            ))
307        });
308
309        if !target_exists {
310            let parent = get_parent(&target_path);
311            self.client.create_dir(parent).map_err(new_std_io_error)?;
312        }
313        if !should_append {
314            initial_size = 0;
315        }
316
317        let mut open_options = self.client.open_file();
318        open_options.create(true);
319        if should_append {
320            open_options.append(true);
321        } else {
322            open_options.write(true);
323        }
324
325        let f = open_options
326            .async_open(tmp_path.as_ref().unwrap_or(&target_path))
327            .await
328            .map_err(new_std_io_error)?;
329
330        Ok((
331            RpWrite::new(),
332            HdfsWriter::new(
333                target_path,
334                tmp_path,
335                f,
336                Arc::clone(&self.client),
337                target_exists,
338                initial_size,
339            ),
340        ))
341    }
342
343    async fn delete(&self) -> Result<(RpDelete, Self::Deleter)> {
344        Ok((
345            RpDelete::default(),
346            oio::OneShotDeleter::new(HdfsDeleter::new(Arc::new(self.clone()))),
347        ))
348    }
349
350    async fn list(&self, path: &str, _: OpList) -> Result<(RpList, Self::Lister)> {
351        let p = build_rooted_abs_path(&self.root, path);
352
353        let f = match self.client.read_dir(&p) {
354            Ok(f) => f,
355            Err(e) => {
356                return if e.kind() == io::ErrorKind::NotFound {
357                    Ok((RpList::default(), None))
358                } else {
359                    Err(new_std_io_error(e))
360                }
361            }
362        };
363
364        let rd = HdfsLister::new(&self.root, f, path);
365
366        Ok((RpList::default(), Some(rd)))
367    }
368
369    async fn rename(&self, from: &str, to: &str, _args: OpRename) -> Result<RpRename> {
370        let from_path = build_rooted_abs_path(&self.root, from);
371        self.client.metadata(&from_path).map_err(new_std_io_error)?;
372
373        let to_path = build_rooted_abs_path(&self.root, to);
374        let result = self.client.metadata(&to_path);
375        match result {
376            Err(err) => {
377                // Early return if other error happened.
378                if err.kind() != io::ErrorKind::NotFound {
379                    return Err(new_std_io_error(err));
380                }
381
382                let parent = PathBuf::from(&to_path)
383                    .parent()
384                    .ok_or_else(|| {
385                        Error::new(
386                            ErrorKind::Unexpected,
387                            "path should have parent but not, it must be malformed",
388                        )
389                        .with_context("input", &to_path)
390                    })?
391                    .to_path_buf();
392
393                self.client
394                    .create_dir(&parent.to_string_lossy())
395                    .map_err(new_std_io_error)?;
396            }
397            Ok(metadata) => {
398                if metadata.is_file() {
399                    self.client
400                        .remove_file(&to_path)
401                        .map_err(new_std_io_error)?;
402                } else {
403                    return Err(Error::new(ErrorKind::IsADirectory, "path should be a file")
404                        .with_context("input", &to_path));
405                }
406            }
407        }
408
409        self.client
410            .rename_file(&from_path, &to_path)
411            .map_err(new_std_io_error)?;
412
413        Ok(RpRename::new())
414    }
415}
opendal/services/hdfs/backend.rs

opendal/services/hdfs/
backend.rs
