mirror of
https://github.com/apple/container.git
synced 2026-07-12 12:37:02 +00:00
Noah Thornton
a967399d48
- This adds support for reading configurations from a three layer hierarchy: 1. User provided TOML 2. Install root TOML 3. Code defaults - We add some code to support plugin configurations via the ConfigurationLoader. Each plugin can provide a struct with an accompanying id that gets used to parse the scoped section of the TOML.
121 lines
4.3 KiB
Swift
121 lines
4.3 KiB
Swift
//===----------------------------------------------------------------------===//
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// Copyright © 2026 Apple Inc. and the container project authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//===----------------------------------------------------------------------===//
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import Configuration
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/// A decoder that decodes `Decodable` types from a ``ConfigSnapshotReader``.
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///
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/// `ConfigSnapshotDecoder` bridges Swift's `Decodable` protocol with the configuration
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/// provider system, allowing you to decode structured configuration into typed
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/// Swift values.
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///
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/// ```swift
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/// struct AppConfig: Decodable {
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/// var host: String
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/// var port: Int
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/// var database: DatabaseConfig
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/// }
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///
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/// struct DatabaseConfig: Decodable {
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/// var connectionString: String
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/// var maxConnections: Int
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/// }
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///
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/// let reader = ConfigReader(providers: [envProvider, jsonProvider])
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/// let snapshot = reader.snapshot()
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/// let config = try ConfigSnapshotDecoder().decode(AppConfig.self, from: snapshot)
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/// ```
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///
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/// Nested structs map to dot-separated key paths. In the example above,
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/// `database.connectionString` and `database.maxConnections` are looked up
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/// from the snapshot.
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public struct ConfigSnapshotDecoder: Sendable {
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public var userInfo: [CodingUserInfoKey: any Sendable]
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private let typeDecodingStrategies: [ObjectIdentifier: AnyConfigDecodingStrategy]
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public init(decodingStrategies: [any ConfigDecodingStrategy] = [URLConfigDecodingStrategy()]) {
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self.userInfo = [:]
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var strategies: [ObjectIdentifier: AnyConfigDecodingStrategy] = [:]
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for strategy in decodingStrategies {
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let erased = AnyConfigDecodingStrategy(strategy)
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strategies[erased.valueTypeID] = erased
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}
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self.typeDecodingStrategies = strategies
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}
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public func decode<T: Decodable>(
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_ type: T.Type,
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from snapshot: ConfigSnapshotReader
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) throws -> T {
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if type is any UnsupportedDictionaryDecoding.Type {
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throw DecodingError.typeMismatch(
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T.self,
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DecodingError.Context(
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codingPath: [],
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debugDescription:
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"ConfigSnapshotDecoder does not support decoding dictionaries (got \(T.self)). Represent dynamic keys as nested structs with known property names."
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)
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)
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}
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let decoder = ConfigSnapshotDecoderImpl(
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snapshot: snapshot,
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codingPath: [],
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userInfo: userInfo.mapValues { $0 as Any },
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typeDecodingStrategies: typeDecodingStrategies
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)
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return try T(from: decoder)
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}
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}
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struct ConfigSnapshotDecoderImpl: Decoder {
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let snapshot: ConfigSnapshotReader
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let codingPath: [any CodingKey]
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let userInfo: [CodingUserInfoKey: Any]
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let typeDecodingStrategies: [ObjectIdentifier: AnyConfigDecodingStrategy]
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func container<Key: CodingKey>(
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keyedBy type: Key.Type
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) throws -> KeyedDecodingContainer<Key> {
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KeyedDecodingContainer(
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KeyedContainer<Key>(
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snapshot: snapshot,
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codingPath: codingPath,
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userInfo: userInfo,
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typeDecodingStrategies: typeDecodingStrategies
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)
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)
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}
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func unkeyedContainer() throws -> any UnkeyedDecodingContainer {
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UnkeyedContainer(
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snapshot: snapshot,
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codingPath: codingPath,
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userInfo: userInfo,
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typeDecodingStrategies: typeDecodingStrategies
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)
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}
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func singleValueContainer() throws -> any SingleValueDecodingContainer {
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SingleValueContainer(
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snapshot: snapshot,
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codingPath: codingPath,
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userInfo: userInfo,
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typeDecodingStrategies: typeDecodingStrategies
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)
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}
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}
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