Reintroduce the versioning functions

meilisearch-types/Cargo.toml

@@ -6,6 +6,7 @@ edition = "2021"
 
 [dependencies]
 actix-web = { version = "4.2.1", default-features = false }
+anyhow = "1.0.65"
 csv = "1.1.6"
 either = { version = "1.6.1", features = ["serde"] }
 enum-iterator = "1.1.3"

meilisearch-types/src/lib.rs

@@ -5,10 +5,12 @@ pub mod keys;
 pub mod settings;
 pub mod star_or;
 pub mod tasks;
+pub mod versioning;
 
 pub use milli;
 pub use milli::{heed, Index};
 use uuid::Uuid;
+pub use versioning::VERSION_FILE_NAME;
 
 pub type Document = serde_json::Map<String, serde_json::Value>;
 pub type InstanceUid = Uuid;

meilisearch-types/src/versioning.rs

@@ -0,0 +1,61 @@
+use std::fs;
+use std::io::{self, ErrorKind};
+use std::path::Path;
+
+/// The name of the file that contains the version of the database.
+pub const VERSION_FILE_NAME: &str = "VERSION";
+
+static VERSION_MAJOR: &str = env!("CARGO_PKG_VERSION_MAJOR");
+static VERSION_MINOR: &str = env!("CARGO_PKG_VERSION_MINOR");
+static VERSION_PATCH: &str = env!("CARGO_PKG_VERSION_PATCH");
+
+/// Persists the version of the current Meilisearch binary to a VERSION file
+pub fn create_version_file(db_path: &Path) -> io::Result<()> {
+    let version_path = db_path.join(VERSION_FILE_NAME);
+    fs::write(version_path, format!("{}.{}.{}", VERSION_MAJOR, VERSION_MINOR, VERSION_PATCH))
+}
+
+/// Ensures Meilisearch version is compatible with the database, returns an error versions mismatch.
+pub fn check_version_file(db_path: &Path) -> anyhow::Result<()> {
+    let version_path = db_path.join(VERSION_FILE_NAME);
+
+    match fs::read_to_string(&version_path) {
+        Ok(version) => {
+            let version_components = version.split('.').collect::<Vec<_>>();
+            let (major, minor, patch) = match &version_components[..] {
+                [major, minor, patch] => (major.to_string(), minor.to_string(), patch.to_string()),
+                _ => return Err(VersionFileError::MalformedVersionFile.into()),
+            };
+
+            if major != VERSION_MAJOR || minor != VERSION_MINOR {
+                return Err(VersionFileError::VersionMismatch { major, minor, patch }.into());
+            }
+        }
+        Err(error) => {
+            return match error.kind() {
+                ErrorKind::NotFound => Err(VersionFileError::MissingVersionFile.into()),
+                _ => Err(error.into()),
+            }
+        }
+    }
+
+    Ok(())
+}
+
+#[derive(thiserror::Error, Debug)]
+pub enum VersionFileError {
+    #[error(
+        "Meilisearch (v{}) failed to infer the version of the database.
+        To update Meilisearch please follow our guide on https://docs.meilisearch.com/learn/advanced/updating.html.",
+        env!("CARGO_PKG_VERSION").to_string()
+    )]
+    MissingVersionFile,
+    #[error("Version file is corrupted and thus Meilisearch is unable to determine the version of the database.")]
+    MalformedVersionFile,
+    #[error(
+        "Expected Meilisearch engine version: {major}.{minor}.{patch}, current engine version: {}.
+        To update Meilisearch please follow our guide on https://docs.meilisearch.com/learn/advanced/updating.html.",
+        env!("CARGO_PKG_VERSION").to_string()
+    )]
+    VersionMismatch { major: String, minor: String, patch: String },
+}