new: Add caching to VCS layer. (#161)

* Add caching.

* Use same instance.

* Update changelog.

* Trigger runs.

* Remove comment.

crates/cli/src/commands/ci.rs

@@ -40,7 +40,7 @@ async fn gather_touched_files(
 ) -> Result<TouchedFilePaths, WorkspaceError> {
     print_header("Gathering touched files");
 
-    let vcs = workspace.detect_vcs()?;
+    let vcs = &workspace.vcs;
     let default_branch = vcs.get_default_branch();
     let current_branch = vcs.get_local_branch().await?;
 

crates/cli/src/commands/run.rs

@@ -40,7 +40,7 @@ async fn get_touched_files(
     status: &RunStatus,
     upstream: bool,
 ) -> Result<TouchedFilePaths, WorkspaceError> {
-    let vcs = workspace.detect_vcs()?;
+    let vcs = &workspace.vcs;
 
     let touched_files = if upstream {
         vcs.get_touched_files_between_revisions(vcs.get_default_branch(), "HEAD")

crates/workspace/src/actions/hashing/target.rs

@@ -34,7 +34,7 @@ pub async fn create_target_hasher(
     task: &Task,
     passthrough_args: &[String],
 ) -> Result<TargetHasher, WorkspaceError> {
-    let vcs = workspace.detect_vcs()?;
+    let vcs = &workspace.vcs;
     let globset = task.create_globset()?;
     let mut hasher = TargetHasher::new(workspace.config.node.version.clone());
 

crates/workspace/src/vcs/git.rs

@@ -5,10 +5,13 @@ use ignore::gitignore::{Gitignore, GitignoreBuilder};
 use moon_utils::fs;
 use moon_utils::process::{output_to_string, output_to_trimmed_string, Command};
 use regex::Regex;
-use std::collections::{BTreeMap, HashSet};
+use std::collections::{BTreeMap, HashMap, HashSet};
 use std::path::{Path, PathBuf};
+use std::sync::Arc;
+use tokio::sync::RwLock;
 
 pub struct Git {
+    cache: Arc<RwLock<HashMap<String, String>>>,
     default_branch: String,
     ignore: Option<Gitignore>,
     working_dir: PathBuf,
@@ -30,6 +33,7 @@ impl Git {
         }
 
         Ok(Git {
+            cache: Arc::new(RwLock::new(HashMap::new())),
             default_branch: String::from(default_branch),
             ignore,
             working_dir: working_dir.to_path_buf(),
@@ -71,13 +75,30 @@ impl Git {
     }
 
     async fn run_command(&self, command: &mut Command, trim: bool) -> VcsResult<String> {
-        let output = command.exec_capture_output().await?;
+        let (cache_key, _) = command.get_command_line();
+
+        // Read first before locking with a write
+        {
+            let cache = self.cache.read().await;
 
-        if trim {
-            return Ok(output_to_trimmed_string(&output.stdout));
+            if cache.contains_key(&cache_key) {
+                return Ok(cache.get(&cache_key).unwrap().clone());
+            }
         }
 
-        Ok(output_to_string(&output.stdout))
+        // Otherwise lock and calculate a new value to write
+        let mut cache = self.cache.write().await;
+        let output = command.exec_capture_output().await?;
+
+        let value = if trim {
+            output_to_trimmed_string(&output.stdout)
+        } else {
+            output_to_string(&output.stdout)
+        };
+
+        cache.insert(cache_key.to_owned(), value.clone());
+
+        Ok(value)
     }
 }
 
@@ -147,6 +168,7 @@ impl Vcs for Git {
                 true,
             )
             .await?;
+
         let mut map = BTreeMap::new();
 
         if output.is_empty() {

crates/workspace/src/vcs/svn.rs

@@ -3,21 +3,25 @@ use async_trait::async_trait;
 use moon_utils::fs;
 use moon_utils::process::{output_to_string, output_to_trimmed_string, Command};
 use regex::Regex;
-use std::collections::{BTreeMap, HashSet};
+use std::collections::{BTreeMap, HashMap, HashSet};
 use std::fs::metadata;
 use std::path::{Path, PathBuf};
+use std::sync::Arc;
 use std::time::SystemTime;
+use tokio::sync::RwLock;
 
 // TODO: This code hasn't been tested yet and may not be accurate!
 
 pub struct Svn {
+    cache: Arc<RwLock<HashMap<String, String>>>,
     default_branch: String,
     working_dir: PathBuf,
 }
 
 impl Svn {
     pub fn new(default_branch: &str, working_dir: &Path) -> Self {
         Svn {
+            cache: Arc::new(RwLock::new(HashMap::new())),
             default_branch: String::from(default_branch),
             working_dir: working_dir.to_path_buf(),
         }
@@ -103,13 +107,30 @@ impl Svn {
     }
 
     async fn run_command(&self, command: &mut Command, trim: bool) -> VcsResult<String> {
-        let output = command.exec_capture_output().await?;
+        let (cache_key, _) = command.get_command_line();
+
+        // Read first before locking with a write
+        {
+            let cache = self.cache.read().await;
 
-        if trim {
-            return Ok(output_to_trimmed_string(&output.stdout));
+            if cache.contains_key(&cache_key) {
+                return Ok(cache.get(&cache_key).unwrap().clone());
+            }
         }
 
-        Ok(output_to_string(&output.stdout))
+        // Otherwise lock and calculate a new value to write
+        let mut cache = self.cache.write().await;
+        let output = command.exec_capture_output().await?;
+
+        let value = if trim {
+            output_to_trimmed_string(&output.stdout)
+        } else {
+            output_to_string(&output.stdout)
+        };
+
+        cache.insert(cache_key.to_owned(), value.clone());
+
+        Ok(value)
     }
 }
 

crates/workspace/src/workspace.rs

@@ -145,6 +145,9 @@ pub struct Workspace {
     /// The root `tsconfig.json`.
     pub tsconfig_json: Option<TsConfigJson>,
 
+    /// Configured version control system.
+    pub vcs: Box<dyn Vcs + Send + Sync>,
+
     /// The current working directory.
     pub working_dir: PathBuf,
 }
@@ -178,6 +181,7 @@ impl Workspace {
         let toolchain = Toolchain::create(&root_dir, &config).await?;
         let projects =
             ProjectGraph::create(&root_dir, project_config, &config.projects, &cache).await?;
+        let vcs = VcsManager::load(&config, &root_dir)?;
 
         Ok(Workspace {
             cache,
@@ -187,12 +191,8 @@ impl Workspace {
             root: root_dir,
             toolchain,
             tsconfig_json,
+            vcs,
             working_dir,
         })
     }
-
-    /// Detect the version control system currently being used.
-    pub fn detect_vcs(&self) -> Result<Box<dyn Vcs + Send + Sync>, WorkspaceError> {
-        VcsManager::load(&self.config, &self.working_dir)
-    }
 }

packages/cli/CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## Unreleased
+
+#### 🚀 Updates
+
+- Added caching to our VCS layer which should greatly reduce the amount of `git` commands being
+  executed.
+
 ### 0.4.1
 
 #### 🐞 Fixes