chore(vdev): Drop dependency on cached crate (vectordotdev#19693)

vdev/Cargo.toml

@@ -9,7 +9,6 @@ publish = false
 
 [dependencies]
 anyhow = "1.0.79"
-cached = "0.48.0"
 chrono = { version = "0.4.31", default-features = false, features = ["serde", "clock"] }
 clap.workspace = true
 clap-verbosity-flag = "2.1.2"

vdev/src/platform.rs

@@ -1,8 +1,8 @@
-use cached::proc_macro::once;
 use directories::ProjectDirs;
 
 use std::env::consts::ARCH;
 use std::path::{Path, PathBuf};
+use std::sync::OnceLock;
 
 pub fn canonicalize_path(path: impl AsRef<Path>) -> String {
     let path = path.as_ref();
@@ -12,12 +12,16 @@ pub fn canonicalize_path(path: impl AsRef<Path>) -> String {
         .to_string()
 }
 
-#[once]
-pub fn data_dir() -> PathBuf {
-    _project_dirs().data_local_dir().to_path_buf()
+pub fn data_dir() -> &'static Path {
+    static DATA_DIR: OnceLock<PathBuf> = OnceLock::new();
+    DATA_DIR.get_or_init(|| {
+        ProjectDirs::from("", "vector", "vdev")
+            .expect("Could not determine the project directory")
+            .data_local_dir()
+            .to_path_buf()
+    })
 }
 
-#[once]
 pub fn default_target() -> String {
     if cfg!(windows) {
         format!("{ARCH}-pc-windows-msvc")
@@ -35,8 +39,3 @@ pub fn default_features() -> &'static str {
         "default"
     }
 }
-
-#[once]
-fn _project_dirs() -> ProjectDirs {
-    ProjectDirs::from("", "vector", "vdev").expect("Could not determine the project directory")
-}

vdev/src/testing/state.rs

@@ -9,7 +9,7 @@ use super::config::Environment;
 use crate::{platform, util};
 
 static DATA_DIR: Lazy<PathBuf> = Lazy::new(|| {
-    [platform::data_dir().as_path(), Path::new("integration")]
+    [platform::data_dir(), Path::new("integration")]
         .into_iter()
         .collect()
 });