reth_db/
version.rs

1//! Database version utils.
2
3use std::{
4    fs, io,
5    path::{Path, PathBuf},
6};
7
8/// The name of the file that contains the version of the database.
9pub const DB_VERSION_FILE_NAME: &str = "database.version";
10/// The version of the database stored in the [`DB_VERSION_FILE_NAME`] file in the same directory as
11/// database.
12pub const DB_VERSION: u64 = 2;
13
14/// Error when checking a database version using [`check_db_version_file`]
15#[derive(thiserror::Error, Debug)]
16pub enum DatabaseVersionError {
17    /// Unable to determine the version of the database; the file is missing.
18    #[error("unable to determine the version of the database, file is missing")]
19    MissingFile,
20    /// Unable to determine the version of the database; the file is malformed.
21    #[error("unable to determine the version of the database, file is malformed")]
22    MalformedFile,
23    /// Breaking database change detected.
24    ///
25    /// Your database version is incompatible with the latest database version.
26    #[error(
27        "breaking database change detected: your database version (v{version}) \
28         is incompatible with the latest database version (v{DB_VERSION})"
29    )]
30    VersionMismatch {
31        /// The detected version in the database.
32        version: u64,
33    },
34    /// IO error occurred while reading the database version file.
35    #[error("IO error occurred while reading {path}: {err}")]
36    IORead {
37        /// The encountered IO error.
38        err: io::Error,
39        /// The path to the database version file.
40        path: PathBuf,
41    },
42}
43
44/// Checks the database version file with [`DB_VERSION_FILE_NAME`] name.
45///
46/// Returns [Ok] if file is found and has one line which equals to [`DB_VERSION`].
47/// Otherwise, returns different [`DatabaseVersionError`] error variants.
48pub fn check_db_version_file<P: AsRef<Path>>(db_path: P) -> Result<(), DatabaseVersionError> {
49    let version = get_db_version(db_path)?;
50    if version != DB_VERSION {
51        return Err(DatabaseVersionError::VersionMismatch { version })
52    }
53
54    Ok(())
55}
56
57/// Returns the database version from file with [`DB_VERSION_FILE_NAME`] name.
58///
59/// Returns [Ok] if file is found and contains a valid version.
60/// Otherwise, returns different [`DatabaseVersionError`] error variants.
61pub fn get_db_version<P: AsRef<Path>>(db_path: P) -> Result<u64, DatabaseVersionError> {
62    let version_file_path = db_version_file_path(db_path);
63    match fs::read_to_string(&version_file_path) {
64        Ok(raw_version) => {
65            Ok(raw_version.parse::<u64>().map_err(|_| DatabaseVersionError::MalformedFile)?)
66        }
67        Err(err) if err.kind() == io::ErrorKind::NotFound => Err(DatabaseVersionError::MissingFile),
68        Err(err) => Err(DatabaseVersionError::IORead { err, path: version_file_path }),
69    }
70}
71
72/// Creates a database version file with [`DB_VERSION_FILE_NAME`] name containing [`DB_VERSION`]
73/// string.
74///
75/// This function will create a file if it does not exist,
76/// and will entirely replace its contents if it does.
77pub fn create_db_version_file<P: AsRef<Path>>(db_path: P) -> io::Result<()> {
78    fs::write(db_version_file_path(db_path), DB_VERSION.to_string())
79}
80
81/// Returns a database version file path.
82pub fn db_version_file_path<P: AsRef<Path>>(db_path: P) -> PathBuf {
83    db_path.as_ref().join(DB_VERSION_FILE_NAME)
84}
85
86#[cfg(test)]
87mod tests {
88    use super::{check_db_version_file, db_version_file_path, DatabaseVersionError};
89    use assert_matches::assert_matches;
90    use std::fs;
91    use tempfile::tempdir;
92
93    #[test]
94    fn missing_file() {
95        let dir = tempdir().unwrap();
96
97        let result = check_db_version_file(&dir);
98        assert_matches!(result, Err(DatabaseVersionError::MissingFile));
99    }
100
101    #[test]
102    fn malformed_file() {
103        let dir = tempdir().unwrap();
104        fs::write(db_version_file_path(&dir), "invalid-version").unwrap();
105
106        let result = check_db_version_file(&dir);
107        assert_matches!(result, Err(DatabaseVersionError::MalformedFile));
108    }
109
110    #[test]
111    fn version_mismatch() {
112        let dir = tempdir().unwrap();
113        fs::write(db_version_file_path(&dir), "0").unwrap();
114
115        let result = check_db_version_file(&dir);
116        assert_matches!(result, Err(DatabaseVersionError::VersionMismatch { version: 0 }));
117    }
118}
reth_db/version.rs

reth_db/
version.rs
