84ab02af-da5f-49b6-aa4e-20ed6b5f3fd3

Committed 09 Apr 2026 04:48PM UTC coverage: 97.136% (+0.01%) from 97.122%

Build # 84ab02af-da5f-49b6-aa4e-20ed6b5f3fd3

Build Type

push

circleci

Committed by

Haixing-Hu

Commit Message

chore: bump version to 0.7.0

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1221 of 1257 relevant lines covered (97.14%)

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98.33

/src/source/env_config_source.rs

/*******************************************************************************
 *
 *    Copyright (c) 2025 - 2026.
 *    Haixing Hu, Qubit Co. Ltd.
 *
 *    All rights reserved.
 *
 ******************************************************************************/
//! # System Environment Variable Configuration Source
//!
//! Loads configuration from the current process's environment variables.
//!
//! # Key Transformation
//!
//! When a prefix is set, only variables matching the prefix are loaded, and
//! the prefix is stripped from the key name. The key is then lowercased and
//! underscores are converted to dots to produce the config key.
//!
//! For example, with prefix `APP_`:
//! - `APP_SERVER_HOST=localhost` → `server.host = "localhost"`
//! - `APP_SERVER_PORT=8080` → `server.port = "8080"`
//!
//! Without a prefix, all environment variables are loaded as-is.
//!
//! # Author
//!
//! Haixing Hu

use crate::{Config, ConfigResult};

use super::ConfigSource;

/// Configuration source that loads from system environment variables
///
/// # Examples
///
/// ```rust,ignore
/// use qubit_config::source::{EnvConfigSource, ConfigSource};
/// use qubit_config::Config;
///
/// // Load all env vars
/// let source = EnvConfigSource::new();
///
/// // Load only vars with prefix "APP_", strip prefix and normalize key
/// let source = EnvConfigSource::with_prefix("APP_");
///
/// let mut config = Config::new();
/// source.load(&mut config).unwrap();
/// ```
///
/// # Author
///
/// Haixing Hu
#[derive(Debug, Clone)]
pub struct EnvConfigSource {
    /// Optional prefix filter; only variables with this prefix are loaded
    prefix: Option<String>,
    /// Whether to strip the prefix from the key
    strip_prefix: bool,
    /// Whether to convert underscores to dots in the key
    convert_underscores: bool,
    /// Whether to lowercase the key
    lowercase_keys: bool,
}

impl EnvConfigSource {
    /// Creates a new `EnvConfigSource` that loads all environment variables.
    ///
    /// Keys are loaded as-is (no prefix filtering, no transformation).
    ///
    /// # Returns
    ///
    /// A source that ingests every `std::env::vars()` entry.
    pub fn new() -> Self {
        Self {
            prefix: None,
            strip_prefix: false,
            convert_underscores: false,
            lowercase_keys: false,
        }
    }

    /// Creates a new `EnvConfigSource` that filters by prefix and normalizes
    /// keys.
    ///
    /// Only variables with the given prefix are loaded. The prefix is stripped,
    /// the key is lowercased, and underscores are converted to dots.
    ///
    /// # Parameters
    ///
    /// * `prefix` - The prefix to filter by (e.g., `"APP_"`)
    ///
    /// # Returns
    ///
    /// A source with prefix filtering and key normalization enabled.
    pub fn with_prefix(prefix: &str) -> Self {
        Self {
            prefix: Some(prefix.to_string()),
            strip_prefix: true,
            convert_underscores: true,
            lowercase_keys: true,
        }
    }

    /// Creates a new `EnvConfigSource` with a custom prefix and explicit
    /// options.
    ///
    /// # Parameters
    ///
    /// * `prefix` - The prefix to filter by
    /// * `strip_prefix` - Whether to strip the prefix from the key
    /// * `convert_underscores` - Whether to convert underscores to dots
    /// * `lowercase_keys` - Whether to lowercase the key
    ///
    /// # Returns
    ///
    /// A configured [`EnvConfigSource`].
    pub fn with_options(
        prefix: &str,
        strip_prefix: bool,
        convert_underscores: bool,
        lowercase_keys: bool,
    ) -> Self {
        Self {
            prefix: Some(prefix.to_string()),
            strip_prefix,
            convert_underscores,
            lowercase_keys,
        }
    }

    /// Transforms an environment variable key according to the source's
    /// settings.
    ///
    /// # Parameters
    ///
    /// * `key` - Original environment variable name.
    ///
    /// # Returns
    ///
    /// The key after optional prefix strip, lowercasing, and underscore
    /// replacement.
    fn transform_key(&self, key: &str) -> String {
        let mut result = key.to_string();

        if self.strip_prefix {
            if let Some(prefix) = &self.prefix {
                if result.starts_with(prefix.as_str()) {
                    result = result[prefix.len()..].to_string();
                }
            }
        }

        if self.lowercase_keys {
            result = result.to_lowercase();
        }

        if self.convert_underscores {
            result = result.replace('_', ".");
        }

        result
    }
}

impl Default for EnvConfigSource {
    fn default() -> Self {
        Self::new()
    }
}

impl ConfigSource for EnvConfigSource {
    fn load(&self, config: &mut Config) -> ConfigResult<()> {
        for (key, value) in std::env::vars() {
            // Filter by prefix if set
            if let Some(prefix) = &self.prefix {
                if !key.starts_with(prefix.as_str()) {
                    continue;
                }
            }

            let transformed_key = self.transform_key(&key);
            config.set(&transformed_key, value)?;
        }

        Ok(())
    }
}

1	/*******************************************************************************
2	*
3	* Copyright (c) 2025 - 2026.
4	* Haixing Hu, Qubit Co. Ltd.
5	*
6	* All rights reserved.
7	*
8	******************************************************************************/
9	//! # System Environment Variable Configuration Source
10	//!
11	//! Loads configuration from the current process's environment variables.
12	//!
13	//! # Key Transformation
14	//!
15	//! When a prefix is set, only variables matching the prefix are loaded, and
16	//! the prefix is stripped from the key name. The key is then lowercased and
17	//! underscores are converted to dots to produce the config key.
18	//!
19	//! For example, with prefix `APP_`:
20	//! - `APP_SERVER_HOST=localhost` → `server.host = "localhost"`
21	//! - `APP_SERVER_PORT=8080` → `server.port = "8080"`
22	//!
23	//! Without a prefix, all environment variables are loaded as-is.
24	//!
25	//! # Author
26	//!
27	//! Haixing Hu
28
29	use crate::{Config, ConfigResult};
30
31	use super::ConfigSource;
32
33	/// Configuration source that loads from system environment variables
34	///
35	/// # Examples
36	///
37	/// ```rust,ignore
38	/// use qubit_config::source::{EnvConfigSource, ConfigSource};
39	/// use qubit_config::Config;
40	///
41	/// // Load all env vars
42	/// let source = EnvConfigSource::new();
43	///
44	/// // Load only vars with prefix "APP_", strip prefix and normalize key
45	/// let source = EnvConfigSource::with_prefix("APP_");
46	///
47	/// let mut config = Config::new();
48	/// source.load(&mut config).unwrap();
49	/// ```
50	///
51	/// # Author
52	///
53	/// Haixing Hu
54	#[derive(Debug, Clone)]
55	pub struct EnvConfigSource {
56	/// Optional prefix filter; only variables with this prefix are loaded
57	prefix: Option<String>,
58	/// Whether to strip the prefix from the key
59	strip_prefix: bool,
60	/// Whether to convert underscores to dots in the key
61	convert_underscores: bool,
62	/// Whether to lowercase the key
63	lowercase_keys: bool,
64	}
65
66	impl EnvConfigSource {
67	/// Creates a new `EnvConfigSource` that loads all environment variables.
68	///
69	/// Keys are loaded as-is (no prefix filtering, no transformation).
70	///
71	/// # Returns
72	///
73	/// A source that ingests every `std::env::vars()` entry.
74	pub fn new() -> Self {	2✔
75	Self {	2✔
76	prefix: None,	2✔
77	strip_prefix: false,	2✔
78	convert_underscores: false,	2✔
79	lowercase_keys: false,	2✔
80	}	2✔
81	}	2✔
82
83	/// Creates a new `EnvConfigSource` that filters by prefix and normalizes
84	/// keys.
85	///
86	/// Only variables with the given prefix are loaded. The prefix is stripped,
87	/// the key is lowercased, and underscores are converted to dots.
88	///
89	/// # Parameters
90	///
91	/// * `prefix` - The prefix to filter by (e.g., `"APP_"`)
92	///
93	/// # Returns
94	///
95	/// A source with prefix filtering and key normalization enabled.
96	pub fn with_prefix(prefix: &str) -> Self {	6✔
97	Self {	6✔
98	prefix: Some(prefix.to_string()),	6✔
99	strip_prefix: true,	6✔
100	convert_underscores: true,	6✔
101	lowercase_keys: true,	6✔
102	}	6✔
103	}	6✔
104
105	/// Creates a new `EnvConfigSource` with a custom prefix and explicit
106	/// options.
107	///
108	/// # Parameters
109	///
110	/// * `prefix` - The prefix to filter by
111	/// * `strip_prefix` - Whether to strip the prefix from the key
112	/// * `convert_underscores` - Whether to convert underscores to dots
113	/// * `lowercase_keys` - Whether to lowercase the key
114	///
115	/// # Returns
116	///
117	/// A configured [`EnvConfigSource`].
118	pub fn with_options(	2✔
119	prefix: &str,	2✔
120	strip_prefix: bool,	2✔
121	convert_underscores: bool,	2✔
122	lowercase_keys: bool,	2✔
123	) -> Self {	2✔
124	Self {	2✔
125	prefix: Some(prefix.to_string()),	2✔
126	strip_prefix,	2✔
127	convert_underscores,	2✔
128	lowercase_keys,	2✔
129	}	2✔
130	}	2✔
131
132	/// Transforms an environment variable key according to the source's
133	/// settings.
134	///
135	/// # Parameters
136	///
137	/// * `key` - Original environment variable name.
138	///
139	/// # Returns
140	///
141	/// The key after optional prefix strip, lowercasing, and underscore
142	/// replacement.
143	fn transform_key(&self, key: &str) -> String {	145✔
144	let mut result = key.to_string();	145✔
145
146	if self.strip_prefix {	145✔
147	if let Some(prefix) = &self.prefix {	7✔
148	if result.starts_with(prefix.as_str()) {	7✔
149	result = result[prefix.len()..].to_string();	7✔
150	}	7✔
151	}	×
152	}	138✔
153
154	if self.lowercase_keys {	145✔
155	result = result.to_lowercase();	7✔
156	}	138✔
157
158	if self.convert_underscores {	145✔
159	result = result.replace('_', ".");	7✔
160	}	138✔
161
162	result	145✔
163	}	145✔
164	}
165
166	impl Default for EnvConfigSource {
167	fn default() -> Self {	1✔
168	Self::new()	1✔
169	}	1✔
170	}
171
172	impl ConfigSource for EnvConfigSource {
173	fn load(&self, config: &mut Config) -> ConfigResult<()> {	10✔
174	for (key, value) in std::env::vars() {	690✔
175	// Filter by prefix if set
176	if let Some(prefix) = &self.prefix {	690✔
177	if !key.starts_with(prefix.as_str()) {	554✔
178	continue;	545✔
179	}	9✔
180	}	136✔
181
182	let transformed_key = self.transform_key(&key);	145✔
183	config.set(&transformed_key, value)?;	145✔
184	}
185
186	Ok(())	10✔
187	}	10✔
188	}

qubit-ltd / rust-config / 84ab02af-da5f-49b6-aa4e-20ed6b5f3fd3

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