opendal/types/
builder.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;
19
20use serde::de::DeserializeOwned;
21use serde::Serialize;
22
23use crate::raw::*;
24use crate::*;
25
26/// Builder is used to set up underlying services.
27///
28/// This trait allows the developer to define a builder struct that can:
29///
30/// - build a service via builder style API.
31/// - configure in-memory options like `http_client` or `customized_credential_load`.
32///
33/// Usually, users don't need to use or import this trait directly, they can use `Operator` API instead.
34///
35/// For example:
36///
37/// ```
38/// # use anyhow::Result;
39/// use opendal::services::Fs;
40/// use opendal::Operator;
41/// async fn test() -> Result<()> {
42///     // Create fs backend builder.
43///     let mut builder = Fs::default().root("/tmp");
44///
45///     // Build an `Operator` to start operating the storage.
46///     let op: Operator = Operator::new(builder)?.finish();
47///
48///     Ok(())
49/// }
50/// ```
51pub trait Builder: Default + 'static {
52    /// Associated scheme for this builder. It indicates what underlying service is.
53    const SCHEME: Scheme;
54    /// Associated configuration for this builder.
55    type Config: Configurator;
56
57    /// Consume the accessor builder to build a service.
58    fn build(self) -> Result<impl Access>;
59}
60
61/// Dummy implementation of builder
62impl Builder for () {
63    const SCHEME: Scheme = Scheme::Custom("dummy");
64    type Config = ();
65
66    fn build(self) -> Result<impl Access> {
67        Ok(())
68    }
69}
70
71/// Configurator is used to configure the underlying service.
72///
73/// This trait allows the developer to define a configuration struct that can:
74///
75/// - deserialize from an iterator like hashmap or vector.
76/// - convert into a service builder and finally build the underlying services.
77///
78/// Usually, users don't need to use or import this trait directly, they can use `Operator` API instead.
79///
80/// For example:
81///
82/// ```
83/// # use anyhow::Result;
84/// use std::collections::HashMap;
85///
86/// use opendal::services::MemoryConfig;
87/// use opendal::Operator;
88/// async fn test() -> Result<()> {
89///     let mut cfg = MemoryConfig::default();
90///     cfg.root = Some("/".to_string());
91///
92///     // Build an `Operator` to start operating the storage.
93///     let op: Operator = Operator::from_config(cfg)?.finish();
94///
95///     Ok(())
96/// }
97/// ```
98///
99/// Some service builder might contain in memory options like `http_client` . Users can call
100/// `into_builder` to convert the configuration into a builder instead.
101///
102/// ```
103/// # use anyhow::Result;
104/// use std::collections::HashMap;
105///
106/// use opendal::raw::HttpClient;
107/// use opendal::services::S3Config;
108/// use opendal::Configurator;
109/// use opendal::Operator;
110///
111/// async fn test() -> Result<()> {
112///     let mut cfg = S3Config::default();
113///     cfg.root = Some("/".to_string());
114///     cfg.bucket = "test".to_string();
115///
116///     let builder = cfg.into_builder();
117///     let builder = builder.http_client(HttpClient::new()?);
118///
119///     // Build an `Operator` to start operating the storage.
120///     let op: Operator = Operator::new(builder)?.finish();
121///
122///     Ok(())
123/// }
124/// ```
125pub trait Configurator: Serialize + DeserializeOwned + Debug + 'static {
126    /// Associated builder for this configuration.
127    type Builder: Builder;
128
129    /// Deserialize from an iterator.
130    ///
131    /// This API is provided by opendal, developer should not implement it.
132    fn from_iter(iter: impl IntoIterator<Item = (String, String)>) -> Result<Self> {
133        let cfg = ConfigDeserializer::new(iter.into_iter().collect());
134
135        Self::deserialize(cfg).map_err(|err| {
136            Error::new(ErrorKind::ConfigInvalid, "failed to deserialize config").set_source(err)
137        })
138    }
139
140    /// Convert this configuration into a service builder.
141    fn into_builder(self) -> Self::Builder;
142}
143
144impl Configurator for () {
145    type Builder = ();
146
147    fn into_builder(self) -> Self::Builder {}
148}
opendal/types/builder.rs

opendal/types/
builder.rs
