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::sync::Arc;
22
23use log::debug;
24
25use super::HDFS_SCHEME;
26use super::core::HdfsCore;
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
35#[doc = include_str!("docs.md")]
36#[derive(Default)]
37pub struct HdfsBuilder {
38    pub(super) config: HdfsConfig,
39}
40
41impl Debug for HdfsBuilder {
42    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
43        f.debug_struct("HdfsBuilder")
44            .field("config", &self.config)
45            .finish()
46    }
47}
48
49impl HdfsBuilder {
50    /// Set root of this backend.
51    ///
52    /// All operations will happen under this root.
53    pub fn root(mut self, root: &str) -> Self {
54        self.config.root = if root.is_empty() {
55            None
56        } else {
57            Some(root.to_string())
58        };
59
60        self
61    }
62
63    /// Set name_node of this backend.
64    ///
65    /// Valid format including:
66    ///
67    /// - `default`: using the default setting based on hadoop config.
68    /// - `hdfs://127.0.0.1:9000`: connect to hdfs cluster.
69    pub fn name_node(mut self, name_node: &str) -> Self {
70        if !name_node.is_empty() {
71            self.config.name_node = Some(name_node.to_string())
72        }
73
74        self
75    }
76
77    /// Set kerberos_ticket_cache_path of this backend
78    ///
79    /// This should be configured when kerberos is enabled.
80    pub fn kerberos_ticket_cache_path(mut self, kerberos_ticket_cache_path: &str) -> Self {
81        if !kerberos_ticket_cache_path.is_empty() {
82            self.config.kerberos_ticket_cache_path = Some(kerberos_ticket_cache_path.to_string())
83        }
84        self
85    }
86
87    /// Set user of this backend
88    pub fn user(mut self, user: &str) -> Self {
89        if !user.is_empty() {
90            self.config.user = Some(user.to_string())
91        }
92        self
93    }
94
95    /// Enable append capacity of this backend.
96    ///
97    /// This should be disabled when HDFS runs in non-distributed mode.
98    pub fn enable_append(mut self, enable_append: bool) -> Self {
99        self.config.enable_append = enable_append;
100        self
101    }
102
103    /// Set temp dir for atomic write.
104    ///
105    /// # Notes
106    ///
107    /// - When append is enabled, we will not use atomic write
108    ///   to avoid data loss and performance issue.
109    pub fn atomic_write_dir(mut self, dir: &str) -> Self {
110        self.config.atomic_write_dir = if dir.is_empty() {
111            None
112        } else {
113            Some(String::from(dir))
114        };
115        self
116    }
117}
118
119impl Builder for HdfsBuilder {
120    type Config = HdfsConfig;
121
122    fn build(self) -> Result<impl Access> {
123        debug!("backend build started: {:?}", &self);
124
125        let name_node = match &self.config.name_node {
126            Some(v) => v,
127            None => {
128                return Err(Error::new(ErrorKind::ConfigInvalid, "name node is empty")
129                    .with_context("service", Scheme::Hdfs));
130            }
131        };
132
133        let root = normalize_root(&self.config.root.unwrap_or_default());
134        debug!("backend use root {root}");
135
136        let mut builder = hdrs::ClientBuilder::new(name_node);
137        if let Some(ticket_cache_path) = &self.config.kerberos_ticket_cache_path {
138            builder = builder.with_kerberos_ticket_cache_path(ticket_cache_path.as_str());
139        }
140        if let Some(user) = &self.config.user {
141            builder = builder.with_user(user.as_str());
142        }
143
144        let client = builder.connect().map_err(new_std_io_error)?;
145
146        // Create root dir if not exist.
147        if let Err(e) = client.metadata(&root) {
148            if e.kind() == io::ErrorKind::NotFound {
149                debug!("root {root} is not exist, creating now");
150
151                client.create_dir(&root).map_err(new_std_io_error)?
152            }
153        }
154
155        let atomic_write_dir = self.config.atomic_write_dir;
156
157        // If atomic write dir is not exist, we must create it.
158        if let Some(d) = &atomic_write_dir {
159            if let Err(e) = client.metadata(d) {
160                if e.kind() == io::ErrorKind::NotFound {
161                    client.create_dir(d).map_err(new_std_io_error)?
162                }
163            }
164        }
165
166        Ok(HdfsBackend {
167            core: Arc::new(HdfsCore {
168                info: {
169                    let am = AccessorInfo::default();
170                    am.set_scheme(HDFS_SCHEME)
171                        .set_root(&root)
172                        .set_native_capability(Capability {
173                            stat: true,
174
175                            read: true,
176
177                            write: true,
178                            write_can_append: self.config.enable_append,
179
180                            create_dir: true,
181                            delete: true,
182
183                            list: true,
184
185                            rename: true,
186
187                            shared: true,
188
189                            ..Default::default()
190                        });
191
192                    am.into()
193                },
194                root,
195                atomic_write_dir,
196                client: Arc::new(client),
197            }),
198        })
199    }
200}
201
202/// Backend for hdfs services.
203#[derive(Debug, Clone)]
204pub struct HdfsBackend {
205    core: Arc<HdfsCore>,
206}
207
208impl Access for HdfsBackend {
209    type Reader = HdfsReader<hdrs::AsyncFile>;
210    type Writer = HdfsWriter<hdrs::AsyncFile>;
211    type Lister = Option<HdfsLister>;
212    type Deleter = oio::OneShotDeleter<HdfsDeleter>;
213
214    fn info(&self) -> Arc<AccessorInfo> {
215        self.core.info.clone()
216    }
217
218    async fn create_dir(&self, path: &str, _: OpCreateDir) -> Result<RpCreateDir> {
219        self.core.hdfs_create_dir(path)?;
220        Ok(RpCreateDir::default())
221    }
222
223    async fn stat(&self, path: &str, _: OpStat) -> Result<RpStat> {
224        let m = self.core.hdfs_stat(path)?;
225        Ok(RpStat::new(m))
226    }
227
228    async fn read(&self, path: &str, args: OpRead) -> Result<(RpRead, Self::Reader)> {
229        let f = self.core.hdfs_read(path, &args).await?;
230
231        Ok((
232            RpRead::new(),
233            HdfsReader::new(f, args.range().size().unwrap_or(u64::MAX) as _),
234        ))
235    }
236
237    async fn write(&self, path: &str, op: OpWrite) -> Result<(RpWrite, Self::Writer)> {
238        let (target_path, tmp_path, f, target_exists, initial_size) =
239            self.core.hdfs_write(path, &op).await?;
240
241        Ok((
242            RpWrite::new(),
243            HdfsWriter::new(
244                target_path,
245                tmp_path,
246                f,
247                Arc::clone(&self.core.client),
248                target_exists,
249                initial_size,
250            ),
251        ))
252    }
253
254    async fn delete(&self) -> Result<(RpDelete, Self::Deleter)> {
255        Ok((
256            RpDelete::default(),
257            oio::OneShotDeleter::new(HdfsDeleter::new(Arc::clone(&self.core))),
258        ))
259    }
260
261    async fn list(&self, path: &str, _: OpList) -> Result<(RpList, Self::Lister)> {
262        match self.core.hdfs_list(path)? {
263            Some(f) => {
264                let rd = HdfsLister::new(&self.core.root, f, path);
265                Ok((RpList::default(), Some(rd)))
266            }
267            None => Ok((RpList::default(), None)),
268        }
269    }
270
271    async fn rename(&self, from: &str, to: &str, _args: OpRename) -> Result<RpRename> {
272        self.core.hdfs_rename(from, to)?;
273        Ok(RpRename::new())
274    }
275}
opendal/services/hdfs/backend.rs

opendal/services/hdfs/
backend.rs
