Make sure /tmp directory does not run out of scope before applicati…

…on ends (#557)

* Make sure tmp dir does not run out of scope before application ends

* Add entry to CHANGELOG.md

CHANGELOG.md

@@ -22,6 +22,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Build a byte buffer over paginated pieces when assembling blobs [#547](https://github.com/p2panda/aquadoggo/pull/547)
 - Stream blob data in chunks to files to not occupy too much memory [#551](https://github.com/p2panda/aquadoggo/pull/551)
 
+## Fixed
+
+- Make sure temporary directory does not run out of scope [#557](https://github.com/p2panda/aquadoggo/pull/557)
+
 ## [0.5.0]
 
 ### Added

aquadoggo_cli/src/config.rs

@@ -4,6 +4,7 @@ use std::convert::TryFrom;
 use std::net::{IpAddr, SocketAddr};
 use std::path::PathBuf;
 use std::str::FromStr;
+use std::sync::OnceLock;
 
 use anyhow::{anyhow, bail, Result};
 use aquadoggo::{AllowList, Configuration as NodeConfiguration, NetworkConfiguration};
@@ -16,13 +17,16 @@ use libp2p::multiaddr::Protocol;
 use libp2p::{Multiaddr, PeerId};
 use p2panda_rs::schema::SchemaId;
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
+use tempfile::TempDir;
 
 use crate::utils::absolute_path;
 
 const WILDCARD: &str = "*";
 
 const CONFIG_FILE_NAME: &str = "config.toml";
 
+static TMP_DIR: OnceLock<TempDir> = OnceLock::new();
+
 type ConfigFilePath = Option<PathBuf>;
 
 /// Get configuration from 1. .toml file, 2. environment variables and 3. command line arguments
@@ -352,11 +356,15 @@ impl TryFrom<Configuration> for NodeConfiguration {
         // Create a temporary blobs directory when none was given
         let blobs_base_path = match value.blobs_base_path {
             Some(path) => path,
-            None => {
-                let tmp_dir = tempfile::TempDir::new()
-                    .map_err(|_| anyhow!("Could not create temporary directory to store blobs"))?;
-                tmp_dir.path().to_path_buf()
-            }
+            None => TMP_DIR
+                .get_or_init(|| {
+                    // Initialise a `TempDir` instance globally to make sure it does not run out of
+                    // scope and gets deleted before the end of the application runtime
+                    tempfile::TempDir::new()
+                        .expect("Could not create temporary directory to store blobs")
+                })
+                .path()
+                .to_path_buf(),
         };
 
         Ok(NodeConfiguration {