aws_types/
app_name.rs

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1/*
2 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
3 * SPDX-License-Identifier: Apache-2.0
4 */
5
6//! New-type for a configurable app name.
7
8use aws_smithy_types::config_bag::{Storable, StoreReplace};
9use std::borrow::Cow;
10use std::error::Error;
11use std::fmt;
12use std::sync::atomic::{AtomicBool, Ordering};
13
14static APP_NAME_LEN_RECOMMENDATION_WARN_EMITTED: AtomicBool = AtomicBool::new(false);
15
16/// App name that can be configured with an AWS SDK client to become part of the user agent string.
17///
18/// This name is used to identify the application in the user agent that gets sent along with requests.
19///
20/// The name may only have alphanumeric characters and any of these characters:
21/// ```text
22/// !#$%&'*+-.^_`|~
23/// ```
24/// Spaces are not allowed.
25///
26/// App names are recommended to be no more than 50 characters.
27#[derive(Clone, Debug, PartialEq, Eq)]
28pub struct AppName(Cow<'static, str>);
29
30impl AsRef<str> for AppName {
31    fn as_ref(&self) -> &str {
32        &self.0
33    }
34}
35
36impl fmt::Display for AppName {
37    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
38        write!(f, "{}", self.0)
39    }
40}
41
42impl Storable for AppName {
43    type Storer = StoreReplace<AppName>;
44}
45
46impl AppName {
47    /// Creates a new app name.
48    ///
49    /// This will return an `InvalidAppName` error if the given name doesn't meet the
50    /// character requirements. See [`AppName`] for details on these requirements.
51    pub fn new(app_name: impl Into<Cow<'static, str>>) -> Result<Self, InvalidAppName> {
52        let app_name = app_name.into();
53
54        if app_name.is_empty() {
55            return Err(InvalidAppName);
56        }
57        fn valid_character(c: char) -> bool {
58            match c {
59                _ if c.is_ascii_alphanumeric() => true,
60                '!' | '#' | '$' | '%' | '&' | '\'' | '*' | '+' | '-' | '.' | '^' | '_' | '`'
61                | '|' | '~' => true,
62                _ => false,
63            }
64        }
65        if !app_name.chars().all(valid_character) {
66            return Err(InvalidAppName);
67        }
68        if app_name.len() > 50 {
69            if let Ok(false) = APP_NAME_LEN_RECOMMENDATION_WARN_EMITTED.compare_exchange(
70                false,
71                true,
72                Ordering::Acquire,
73                Ordering::Relaxed,
74            ) {
75                tracing::warn!(
76                    "The `app_name` set when configuring the SDK client is recommended \
77                     to have no more than 50 characters."
78                )
79            }
80        }
81        Ok(Self(app_name))
82    }
83}
84
85/// Error for when an app name doesn't meet character requirements.
86///
87/// See [`AppName`] for details on these requirements.
88#[derive(Debug)]
89#[non_exhaustive]
90pub struct InvalidAppName;
91
92impl Error for InvalidAppName {}
93
94impl fmt::Display for InvalidAppName {
95    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
96        write!(
97            f,
98            "The app name can only have alphanumeric characters, or any of \
99             '!' |  '#' |  '$' |  '%' |  '&' |  '\\'' |  '*' |  '+' |  '-' | \
100             '.' |  '^' |  '_' |  '`' |  '|' |  '~'"
101        )
102    }
103}
104
105#[cfg(test)]
106mod tests {
107    use super::AppName;
108    use crate::app_name::APP_NAME_LEN_RECOMMENDATION_WARN_EMITTED;
109    use std::sync::atomic::Ordering;
110
111    #[test]
112    fn validation() {
113        assert!(AppName::new("asdf1234ASDF!#$%&'*+-.^_`|~").is_ok());
114        assert!(AppName::new("foo bar").is_err());
115        assert!(AppName::new("🚀").is_err());
116        assert!(AppName::new("").is_err());
117    }
118
119    #[tracing_test::traced_test]
120    #[test]
121    fn log_warn_once() {
122        // Pre-condition: make sure we start in the expected state of having never logged this
123        assert!(!APP_NAME_LEN_RECOMMENDATION_WARN_EMITTED.load(Ordering::Relaxed));
124
125        // Verify a short app name doesn't log
126        AppName::new("not-long").unwrap();
127        assert!(!logs_contain(
128            "is recommended to have no more than 50 characters"
129        ));
130        assert!(!APP_NAME_LEN_RECOMMENDATION_WARN_EMITTED.load(Ordering::Relaxed));
131
132        // Verify a long app name logs
133        AppName::new("greaterthanfiftycharactersgreaterthanfiftycharacters").unwrap();
134        assert!(logs_contain(
135            "is recommended to have no more than 50 characters"
136        ));
137        assert!(APP_NAME_LEN_RECOMMENDATION_WARN_EMITTED.load(Ordering::Relaxed));
138
139        // Now verify it only logs once ever
140
141        // HACK: there's no way to reset tracing-test, so just
142        // reach into its internals and clear it manually
143        tracing_test::internal::global_buf().lock().unwrap().clear();
144
145        AppName::new("greaterthanfiftycharactersgreaterthanfiftycharacters").unwrap();
146        assert!(!logs_contain(
147            "is recommended to have no more than 50 characters"
148        ));
149    }
150}
aws_types/app_name.rs

aws_types/
app_name.rs
