feat!: add configurable extractors

Author: brianheineman

examples/archive_async/src/main.rs

@@ -7,11 +7,11 @@ use postgresql_archive::{
 
 #[tokio::main]
 async fn main() -> Result<()> {
+    let url = THESEUS_POSTGRESQL_BINARIES_URL;
     let version_req = VersionReq::STAR;
-    let (archive_version, archive) =
-        get_archive(THESEUS_POSTGRESQL_BINARIES_URL, &version_req).await?;
+    let (archive_version, archive) = get_archive(url, &version_req).await?;
     let out_dir = tempfile::tempdir()?.into_path();
-    extract(&archive, &out_dir).await?;
+    extract(url, &archive, &out_dir).await?;
     println!(
         "PostgreSQL {} extracted to {}",
         archive_version,

examples/archive_sync/src/main.rs

@@ -5,10 +5,11 @@ use postgresql_archive::blocking::{extract, get_archive};
 use postgresql_archive::{Result, VersionReq, THESEUS_POSTGRESQL_BINARIES_URL};
 
 fn main() -> Result<()> {
+    let url = THESEUS_POSTGRESQL_BINARIES_URL;
     let version_req = VersionReq::STAR;
-    let (archive_version, archive) = get_archive(THESEUS_POSTGRESQL_BINARIES_URL, &version_req)?;
+    let (archive_version, archive) = get_archive(url, &version_req)?;
     let out_dir = tempfile::tempdir()?.into_path();
-    extract(&archive, &out_dir)?;
+    extract(url, &archive, &out_dir)?;
     println!(
         "PostgreSQL {} extracted to {}",
         archive_version,

postgresql_archive/benches/archive.rs

@@ -24,7 +24,7 @@ fn bench_extract(criterion: &mut Criterion) -> Result<()> {
 fn extract_archive(archive: &Vec<u8>) -> Result<()> {
     let out_dir = tempfile::tempdir()?.path().to_path_buf();
     create_dir_all(&out_dir)?;
-    extract(archive, &out_dir)?;
+    extract(THESEUS_POSTGRESQL_BINARIES_URL, archive, &out_dir)?;
     remove_dir_all(&out_dir)?;
     Ok(())
 }

postgresql_archive/src/archive.rs

@@ -1,20 +1,11 @@
 //! Manage PostgreSQL archives
 #![allow(dead_code)]
 
-use crate::error::Error::Unexpected;
 use crate::error::Result;
-use crate::repository;
-use flate2::bufread::GzDecoder;
-use human_bytes::human_bytes;
-use num_format::{Locale, ToFormattedString};
+use crate::{extractor, repository};
 use semver::{Version, VersionReq};
-use std::fs::{create_dir_all, remove_dir_all, remove_file, rename, File};
-use std::io::{copy, BufReader, Cursor};
-use std::path::{Path, PathBuf};
-use std::thread::sleep;
-use std::time::Duration;
-use tar::Archive;
-use tracing::{debug, instrument, warn};
+use std::path::Path;
+use tracing::instrument;
 
 pub const THESEUS_POSTGRESQL_BINARIES_URL: &str =
     "https://github.com/theseus-rs/postgresql-binaries";
@@ -47,164 +38,15 @@ pub async fn get_archive(url: &str, version_req: &VersionReq) -> Result<(Version
     Ok((version, bytes))
 }
 
-/// Acquires a lock file in the [out_dir](Path) to prevent multiple processes from extracting the
-/// archive at the same time.
-///
-/// # Errors
-/// * If the lock file cannot be acquired.
-#[instrument(level = "debug")]
-fn acquire_lock(out_dir: &Path) -> Result<PathBuf> {
-    let lock_file = out_dir.join("postgresql-archive.lock");
-
-    if lock_file.is_file() {
-        let metadata = lock_file.metadata()?;
-        let created = metadata.created()?;
-
-        if created.elapsed()?.as_secs() > 300 {
-            warn!(
-                "Stale lock file detected; removing file to attempt process recovery: {}",
-                lock_file.to_string_lossy()
-            );
-            remove_file(&lock_file)?;
-        }
-    }
-
-    debug!(
-        "Attempting to acquire lock: {}",
-        lock_file.to_string_lossy()
-    );
-
-    for _ in 0..30 {
-        let lock = std::fs::OpenOptions::new()
-            .create(true)
-            .truncate(true)
-            .write(true)
-            .open(&lock_file);
-
-        match lock {
-            Ok(_) => {
-                debug!("Lock acquired: {}", lock_file.to_string_lossy());
-                return Ok(lock_file);
-            }
-            Err(error) => {
-                warn!("unable to acquire lock: {error}");
-                sleep(Duration::from_secs(1));
-            }
-        }
-    }
-
-    Err(Unexpected("Failed to acquire lock".to_string()))
-}
-
 /// Extracts the compressed tar `bytes` to the [out_dir](Path).
 ///
 /// # Errors
 /// Returns an error if the extraction fails.
 #[allow(clippy::cast_precision_loss)]
 #[instrument(skip(bytes))]
-pub async fn extract(bytes: &Vec<u8>, out_dir: &Path) -> Result<()> {
-    let input = BufReader::new(Cursor::new(bytes));
-    let decoder = GzDecoder::new(input);
-    let mut archive = Archive::new(decoder);
-    let mut files = 0;
-    let mut extracted_bytes = 0;
-
-    let parent_dir = if let Some(parent) = out_dir.parent() {
-        parent
-    } else {
-        debug!("No parent directory for {}", out_dir.to_string_lossy());
-        out_dir
-    };
-
-    create_dir_all(parent_dir)?;
-
-    let lock_file = acquire_lock(parent_dir)?;
-    // If the directory already exists, then the archive has already been
-    // extracted by another process.
-    if out_dir.exists() {
-        debug!(
-            "Directory already exists {}; skipping extraction: ",
-            out_dir.to_string_lossy()
-        );
-        remove_file(&lock_file)?;
-        return Ok(());
-    }
-
-    let extract_dir = tempfile::tempdir_in(parent_dir)?.into_path();
-    debug!("Extracting archive to {}", extract_dir.to_string_lossy());
-
-    for archive_entry in archive.entries()? {
-        let mut entry = archive_entry?;
-        let entry_header = entry.header();
-        let entry_type = entry_header.entry_type();
-        let entry_size = entry_header.size()?;
-        #[cfg(unix)]
-        let file_mode = entry_header.mode()?;
-
-        let entry_header_path = entry_header.path()?.to_path_buf();
-        let prefix = match entry_header_path.components().next() {
-            Some(component) => component.as_os_str().to_str().unwrap_or_default(),
-            None => {
-                return Err(Unexpected(
-                    "Failed to get file header path prefix".to_string(),
-                ));
-            }
-        };
-        let stripped_entry_header_path = entry_header_path.strip_prefix(prefix)?.to_path_buf();
-        let mut entry_name = extract_dir.clone();
-        entry_name.push(stripped_entry_header_path);
-
-        if entry_type.is_dir() || entry_name.is_dir() {
-            create_dir_all(&entry_name)?;
-        } else if entry_type.is_file() {
-            let mut output_file = File::create(&entry_name)?;
-            copy(&mut entry, &mut output_file)?;
-
-            files += 1;
-            extracted_bytes += entry_size;
-
-            #[cfg(unix)]
-            {
-                use std::os::unix::fs::PermissionsExt;
-                output_file.set_permissions(std::fs::Permissions::from_mode(file_mode))?;
-            }
-        } else if entry_type.is_symlink() {
-            #[cfg(unix)]
-            if let Some(symlink_target) = entry.link_name()? {
-                let symlink_path = entry_name;
-                std::os::unix::fs::symlink(symlink_target.as_ref(), symlink_path)?;
-            }
-        }
-    }
-
-    if out_dir.exists() {
-        debug!(
-            "Directory already exists {}; skipping rename and removing extraction directory: {}",
-            out_dir.to_string_lossy(),
-            extract_dir.to_string_lossy()
-        );
-        remove_dir_all(&extract_dir)?;
-    } else {
-        debug!(
-            "Renaming {} to {}",
-            extract_dir.to_string_lossy(),
-            out_dir.to_string_lossy()
-        );
-        rename(extract_dir, out_dir)?;
-    }
-
-    if lock_file.is_file() {
-        debug!("Removing lock file: {}", lock_file.to_string_lossy());
-        remove_file(lock_file)?;
-    }
-
-    debug!(
-        "Extracting {} files totalling {}",
-        files.to_formatted_string(&Locale::en),
-        human_bytes(extracted_bytes as f64)
-    );
-
-    Ok(())
+pub async fn extract(url: &str, bytes: &Vec<u8>, out_dir: &Path) -> Result<()> {
+    let extractor_fn = extractor::registry::get(url)?;
+    extractor_fn(bytes, out_dir)
 }
 
 #[cfg(test)]

postgresql_archive/src/blocking/archive.rs

@@ -34,8 +34,8 @@ pub fn get_archive(url: &str, version_req: &VersionReq) -> crate::Result<(Versio
 ///
 /// # Errors
 /// Returns an error if the extraction fails.
-pub fn extract(bytes: &Vec<u8>, out_dir: &Path) -> crate::Result<()> {
+pub fn extract(url: &str, bytes: &Vec<u8>, out_dir: &Path) -> crate::Result<()> {
     RUNTIME
         .handle()
-        .block_on(async move { crate::extract(bytes, out_dir).await })
+        .block_on(async move { crate::extract(url, bytes, out_dir).await })
 }

postgresql_archive/src/error.rs

@@ -31,6 +31,9 @@ pub enum Error {
     /// Unexpected error
     #[error("{0}")]
     Unexpected(String),
+    /// Unsupported extractor
+    #[error("unsupported extractor for '{0}'")]
+    UnsupportedExtractor(String),
     /// Unsupported hasher
     #[error("unsupported hasher for '{0}'")]
     UnsupportedHasher(String),

postgresql_archive/src/extractor/mod.rs

@@ -0,0 +1,2 @@
+pub mod registry;
+pub mod theseus_postgresql_binary;

postgresql_archive/src/extractor/registry.rs

@@ -0,0 +1,121 @@
+use crate::extractor::theseus_postgresql_binary;
+use crate::Error::{PoisonedLock, UnsupportedExtractor};
+use crate::{Result, THESEUS_POSTGRESQL_BINARIES_URL};
+use lazy_static::lazy_static;
+use std::path::Path;
+use std::sync::{Arc, Mutex, RwLock};
+
+lazy_static! {
+    static ref REGISTRY: Arc<Mutex<RepositoryRegistry>> =
+        Arc::new(Mutex::new(RepositoryRegistry::default()));
+}
+
+type SupportsFn = fn(&str) -> Result<bool>;
+type ExtractFn = fn(&Vec<u8>, &Path) -> Result<()>;
+
+/// Singleton struct to store extractors
+#[allow(clippy::type_complexity)]
+struct RepositoryRegistry {
+    extractors: Vec<(Arc<RwLock<SupportsFn>>, Arc<RwLock<ExtractFn>>)>,
+}
+
+impl RepositoryRegistry {
+    /// Creates a new extractor registry.
+    fn new() -> Self {
+        Self {
+            extractors: Vec::new(),
+        }
+    }
+
+    /// Registers an extractor. Newly registered extractors take precedence over existing ones.
+    fn register(&mut self, supports_fn: SupportsFn, extract_fn: ExtractFn) {
+        self.extractors.insert(
+            0,
+            (
+                Arc::new(RwLock::new(supports_fn)),
+                Arc::new(RwLock::new(extract_fn)),
+            ),
+        );
+    }
+
+    /// Gets an extractor that supports the specified URL
+    ///
+    /// # Errors
+    /// * If the URL is not supported.
+    fn get(&self, url: &str) -> Result<ExtractFn> {
+        for (supports_fn, extractor_fn) in &self.extractors {
+            let supports_function = supports_fn
+                .read()
+                .map_err(|error| PoisonedLock(error.to_string()))?;
+            if supports_function(url)? {
+                let extractor_function = extractor_fn
+                    .read()
+                    .map_err(|error| PoisonedLock(error.to_string()))?;
+                return Ok(*extractor_function);
+            }
+        }
+
+        Err(UnsupportedExtractor(url.to_string()))
+    }
+}
+
+impl Default for RepositoryRegistry {
+    /// Creates a new repository registry with the default repositories registered.
+    fn default() -> Self {
+        let mut registry = Self::new();
+        registry.register(
+            |url| Ok(url.starts_with(THESEUS_POSTGRESQL_BINARIES_URL)),
+            theseus_postgresql_binary::extract,
+        );
+        registry
+    }
+}
+
+/// Registers an extractor. Newly registered extractors take precedence over existing ones.
+///
+/// # Errors
+/// * If the registry is poisoned.
+#[allow(dead_code)]
+pub fn register(supports_fn: SupportsFn, extractor_fn: ExtractFn) -> Result<()> {
+    let mut registry = REGISTRY
+        .lock()
+        .map_err(|error| PoisonedLock(error.to_string()))?;
+    registry.register(supports_fn, extractor_fn);
+    Ok(())
+}
+
+/// Gets an extractor that supports the specified URL
+///
+/// # Errors
+/// * If the URL is not supported.
+pub fn get(url: &str) -> Result<ExtractFn> {
+    let registry = REGISTRY
+        .lock()
+        .map_err(|error| PoisonedLock(error.to_string()))?;
+    registry.get(url)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_register() -> Result<()> {
+        register(|url| Ok(url == "https://foo.com"), |_, _| Ok(()))?;
+        let url = "https://foo.com";
+        let extractor = get(url)?;
+        assert!(extractor(&Vec::new(), Path::new("foo")).is_ok());
+        Ok(())
+    }
+
+    #[test]
+    fn test_get_error() {
+        let error = get("foo").unwrap_err();
+        assert_eq!("unsupported extractor for 'foo'", error.to_string());
+    }
+
+    #[test]
+    fn test_get_theseus_postgresql_binaries() {
+        assert!(get(THESEUS_POSTGRESQL_BINARIES_URL).is_ok());
+    }
+}