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::io;
19use std::sync::Arc;
20
21use log::debug;
22
23use super::HDFS_SCHEME;
24use super::config::HdfsConfig;
25use super::core::HdfsCore;
26use super::deleter::HdfsDeleter;
27use super::lister::HdfsLister;
28use super::reader::HdfsReader;
29use super::writer::HdfsWriter;
30use crate::raw::*;
31use crate::*;
32
33#[doc = include_str!("docs.md")]
34#[derive(Debug, Default)]
35pub struct HdfsBuilder {
36    pub(super) config: HdfsConfig,
37}
38
39impl HdfsBuilder {
40    /// Set root of this backend.
41    ///
42    /// All operations will happen under this root.
43    pub fn root(mut self, root: &str) -> Self {
44        self.config.root = if root.is_empty() {
45            None
46        } else {
47            Some(root.to_string())
48        };
49
50        self
51    }
52
53    /// Set name_node of this backend.
54    ///
55    /// Valid format including:
56    ///
57    /// - `default`: using the default setting based on hadoop config.
58    /// - `hdfs://127.0.0.1:9000`: connect to hdfs cluster.
59    pub fn name_node(mut self, name_node: &str) -> Self {
60        if !name_node.is_empty() {
61            self.config.name_node = Some(name_node.to_string())
62        }
63
64        self
65    }
66
67    /// Set kerberos_ticket_cache_path of this backend
68    ///
69    /// This should be configured when kerberos is enabled.
70    pub fn kerberos_ticket_cache_path(mut self, kerberos_ticket_cache_path: &str) -> Self {
71        if !kerberos_ticket_cache_path.is_empty() {
72            self.config.kerberos_ticket_cache_path = Some(kerberos_ticket_cache_path.to_string())
73        }
74        self
75    }
76
77    /// Set user of this backend
78    pub fn user(mut self, user: &str) -> Self {
79        if !user.is_empty() {
80            self.config.user = Some(user.to_string())
81        }
82        self
83    }
84
85    /// Enable append capacity of this backend.
86    ///
87    /// This should be disabled when HDFS runs in non-distributed mode.
88    pub fn enable_append(mut self, enable_append: bool) -> Self {
89        self.config.enable_append = enable_append;
90        self
91    }
92
93    /// Set temp dir for atomic write.
94    ///
95    /// # Notes
96    ///
97    /// - When append is enabled, we will not use atomic write
98    ///   to avoid data loss and performance issue.
99    pub fn atomic_write_dir(mut self, dir: &str) -> Self {
100        self.config.atomic_write_dir = if dir.is_empty() {
101            None
102        } else {
103            Some(String::from(dir))
104        };
105        self
106    }
107}
108
109impl Builder for HdfsBuilder {
110    type Config = HdfsConfig;
111
112    fn build(self) -> Result<impl Access> {
113        debug!("backend build started: {:?}", &self);
114
115        let name_node = match &self.config.name_node {
116            Some(v) => v,
117            None => {
118                return Err(Error::new(ErrorKind::ConfigInvalid, "name node is empty")
119                    .with_context("service", HDFS_SCHEME));
120            }
121        };
122
123        let root = normalize_root(&self.config.root.unwrap_or_default());
124        debug!("backend use root {root}");
125
126        let mut builder = hdrs::ClientBuilder::new(name_node);
127        if let Some(ticket_cache_path) = &self.config.kerberos_ticket_cache_path {
128            builder = builder.with_kerberos_ticket_cache_path(ticket_cache_path.as_str());
129        }
130        if let Some(user) = &self.config.user {
131            builder = builder.with_user(user.as_str());
132        }
133
134        let client = builder.connect().map_err(new_std_io_error)?;
135
136        // Create root dir if not exist.
137        if let Err(e) = client.metadata(&root) {
138            if e.kind() == io::ErrorKind::NotFound {
139                debug!("root {root} is not exist, creating now");
140
141                client.create_dir(&root).map_err(new_std_io_error)?
142            }
143        }
144
145        let atomic_write_dir = self.config.atomic_write_dir;
146
147        // If atomic write dir is not exist, we must create it.
148        if let Some(d) = &atomic_write_dir {
149            if let Err(e) = client.metadata(d) {
150                if e.kind() == io::ErrorKind::NotFound {
151                    client.create_dir(d).map_err(new_std_io_error)?
152                }
153            }
154        }
155
156        Ok(HdfsBackend {
157            core: Arc::new(HdfsCore {
158                info: {
159                    let am = AccessorInfo::default();
160                    am.set_scheme(HDFS_SCHEME)
161                        .set_root(&root)
162                        .set_native_capability(Capability {
163                            stat: true,
164
165                            read: true,
166
167                            write: true,
168                            write_can_append: self.config.enable_append,
169
170                            create_dir: true,
171                            delete: true,
172
173                            list: true,
174
175                            rename: true,
176
177                            shared: true,
178
179                            ..Default::default()
180                        });
181
182                    am.into()
183                },
184                root,
185                atomic_write_dir,
186                client: Arc::new(client),
187            }),
188        })
189    }
190}
191
192/// Backend for hdfs services.
193#[derive(Debug, Clone)]
194pub struct HdfsBackend {
195    core: Arc<HdfsCore>,
196}
197
198impl Access for HdfsBackend {
199    type Reader = HdfsReader<hdrs::AsyncFile>;
200    type Writer = HdfsWriter<hdrs::AsyncFile>;
201    type Lister = Option<HdfsLister>;
202    type Deleter = oio::OneShotDeleter<HdfsDeleter>;
203
204    fn info(&self) -> Arc<AccessorInfo> {
205        self.core.info.clone()
206    }
207
208    async fn create_dir(&self, path: &str, _: OpCreateDir) -> Result<RpCreateDir> {
209        self.core.hdfs_create_dir(path)?;
210        Ok(RpCreateDir::default())
211    }
212
213    async fn stat(&self, path: &str, _: OpStat) -> Result<RpStat> {
214        let m = self.core.hdfs_stat(path)?;
215        Ok(RpStat::new(m))
216    }
217
218    async fn read(&self, path: &str, args: OpRead) -> Result<(RpRead, Self::Reader)> {
219        let f = self.core.hdfs_read(path, &args).await?;
220
221        Ok((
222            RpRead::new(),
223            HdfsReader::new(f, args.range().size().unwrap_or(u64::MAX) as _),
224        ))
225    }
226
227    async fn write(&self, path: &str, op: OpWrite) -> Result<(RpWrite, Self::Writer)> {
228        let (target_path, tmp_path, f, target_exists, initial_size) =
229            self.core.hdfs_write(path, &op).await?;
230
231        Ok((
232            RpWrite::new(),
233            HdfsWriter::new(
234                target_path,
235                tmp_path,
236                f,
237                Arc::clone(&self.core.client),
238                target_exists,
239                initial_size,
240            ),
241        ))
242    }
243
244    async fn delete(&self) -> Result<(RpDelete, Self::Deleter)> {
245        Ok((
246            RpDelete::default(),
247            oio::OneShotDeleter::new(HdfsDeleter::new(Arc::clone(&self.core))),
248        ))
249    }
250
251    async fn list(&self, path: &str, _: OpList) -> Result<(RpList, Self::Lister)> {
252        match self.core.hdfs_list(path)? {
253            Some(f) => {
254                let rd = HdfsLister::new(&self.core.root, f, path);
255                Ok((RpList::default(), Some(rd)))
256            }
257            None => Ok((RpList::default(), None)),
258        }
259    }
260
261    async fn rename(&self, from: &str, to: &str, _args: OpRename) -> Result<RpRename> {
262        self.core.hdfs_rename(from, to)?;
263        Ok(RpRename::new())
264    }
265}
opendal/services/hdfs/backend.rs

opendal/services/hdfs/
backend.rs
