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feat: versioning of configuration files

dev
meeg_leeto 7 months ago
parent
commit
8c12dfc132
  1. 96
      src/main.rs

96
src/main.rs

@ -145,6 +145,12 @@ mod conf { @@ -145,6 +145,12 @@ mod conf {
/// example). See the definition of each of the member structs for more
/// information.
pub struct Config {
/// The "version" of the configuration, corresponding to the MAJOR in
/// semantic versioning. Should be increased every time the
/// configuration structure suffers breaking changes.
/// This value is optional because sufficiently old configuration files
/// may not have a version field.
pub version: Option<usize>,
/// Configuration regarding the Redis database.
pub db: DbConfig,
/// Configuration regarding the types of (URL shorten) slugs produced.
@ -153,6 +159,32 @@ mod conf { @@ -153,6 +159,32 @@ mod conf {
pub serve_rules: ServeRules,
}
/// Get the configuration version field that this version of lonk expects.
pub fn config_version() -> usize {
usize::from_str(env!("CARGO_PKG_VERSION_MAJOR")).unwrap()
}
pub enum ConfigParseError {
SerdeError(serde_json::error::Error),
OldVersion(usize),
}
impl Config {
pub fn from_sync_buffer<R: std::io::Read>(
buffer: std::io::BufReader<R>,
) -> Result<Self, ConfigParseError> {
let parsed: Config =
serde_json::from_reader(buffer).map_err(|err| ConfigParseError::SerdeError(err))?;
let parsed_version = parsed.version.unwrap_or(0);
if parsed_version != config_version() {
return Err(ConfigParseError::OldVersion(parsed_version));
}
Ok(parsed)
}
}
// Default implementations
impl Default for DbConfig {
@ -210,6 +242,7 @@ mod conf { @@ -210,6 +242,7 @@ mod conf {
impl Default for Config {
fn default() -> Self {
Self {
version: Some(config_version()),
db: Default::default(),
slug_rules: Default::default(),
serve_rules: Default::default(),
@ -824,27 +857,45 @@ async fn serve() { @@ -824,27 +857,45 @@ async fn serve() {
),
};
});
let config_buf = std::io::BufReader::new(config_file);
serde_json::from_reader(config_buf).unwrap_or_else(|err| match err.classify() {
serde_json::error::Category::Io => panic!("IO error when reading configuration file."),
serde_json::error::Category::Syntax => panic!(
"Configuration file is syntactically incorrect.
See {}:line {}, column {}.",
&config_file_name,
err.line(),
err.column()
),
serde_json::error::Category::Data => panic!(
"Error deserializing configuration file; expected different data type.
See {}:line {}, column {}.",
&config_file_name,
err.line(),
err.column()
),
serde_json::error::Category::Eof => {
panic!("Unexpected end of file when reading configuration file.")
}
let parse_result = tokio::task::spawn_blocking(move || {
conf::Config::from_sync_buffer(std::io::BufReader::new(config_file))
})
.await
.expect("Tokio error from blocking task.");
match parse_result {
Err(conf::ConfigParseError::SerdeError(err)) => match err.classify() {
serde_json::error::Category::Io => {
panic!("IO error when reading configuration file.")
}
serde_json::error::Category::Syntax => panic!(
"Configuration file is syntactically incorrect.
See {}:line {}, column {}.",
&config_file_name,
err.line(),
err.column()
),
serde_json::error::Category::Data => panic!(
"Error deserializing configuration file; expected different data type.
See {}:line {}, column {}.",
&config_file_name,
err.line(),
err.column()
),
serde_json::error::Category::Eof => {
panic!("Unexpected end of file when reading configuration file.")
}
},
Err(conf::ConfigParseError::OldVersion(old_version)) => {
panic!(
"Configuration file has outdated version.
Expected version field to be {} but got {}.",
old_version,
conf::config_version()
);
}
Ok(config) => config,
}
};
// Create slug factory
@ -934,7 +985,8 @@ fn main() { @@ -934,7 +985,8 @@ fn main() {
serde_json::to_string_pretty(&conf::Config::default())
.expect("Default configuration should always be JSON serializable")
);
} else {
serve();
std::process::exit(0);
}
serve();
}

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