named cache and better error reporting

1 files changed, 14 insertions, 7 deletions

diff --git a/base/src/cache.rs b/base/src/cache.rs
index d840c00..7705a14 100644
--- a/base/src/cache.rs
+++ b/base/src/cache.rs
@@ -1,5 +1,5 @@
 use crate::{AssetLocationExt, CONF};
-use anyhow::anyhow;
+use anyhow::{anyhow, Context};
 use base64::Engine;
 use bincode::{Decode, Encode};
 use jellycommon::AssetLocation;
@@ -27,7 +27,8 @@ pub fn cache_location(seed: &[&str]) -> (usize, AssetLocation) {
     let d = d.finalize();
     let n = d[0] as usize | (d[1] as usize) << 8 | (d[2] as usize) << 16 | (d[3] as usize) << 24;
     let fname = base64::engine::general_purpose::URL_SAFE.encode(d);
-    let fname = &fname[..22]; // about 128 bits
+    let fname = &fname[..22];
+    let fname = format!("{}-{}", seed[0], fname); // about 128 bits
     (n, AssetLocation::Cache(fname.into()))
 }
 
@@ -46,9 +47,13 @@ where
     let (bucket, location) = cache_location(seed);
     // we need a lock even if it exists since somebody might be still in the process of writing.
     let _guard = CACHE_GENERATION_LOCKS[bucket % CACHE_GENERATION_BUCKET_COUNT].lock();
-    let exists = tokio::fs::try_exists(location.path()).await?;
+    let exists = tokio::fs::try_exists(location.path())
+        .await
+        .context("unable to test for cache file existance")?;
     if !exists {
-        let f = tokio::fs::File::create(location.path()).await?;
+        let f = tokio::fs::File::create(location.path())
+            .await
+            .context("creating new cache file")?;
         generate(f).await?;
     }
     drop(_guard);
@@ -64,7 +69,7 @@ where
     let _guard = CACHE_GENERATION_LOCKS[bucket % CACHE_GENERATION_BUCKET_COUNT].blocking_lock();
     let exists = location.path().exists();
     if !exists {
-        let f = std::fs::File::create(location.path())?;
+        let f = std::fs::File::create(location.path()).context("creating new cache file")?;
         generate(f)?;
     }
     drop(_guard);
@@ -101,11 +106,13 @@ where
 
     let location = cache_file(seed, move |mut file| {
         let object = generate()?;
-        bincode::encode_into_std_write(&object, &mut file, bincode::config::standard())?;
+        bincode::encode_into_std_write(&object, &mut file, bincode::config::standard())
+            .context("encoding cache object")?;
         Ok(())
     })?;
     let mut file = std::fs::File::open(location.path())?;
-    let object = bincode::decode_from_std_read::<T, _, _>(&mut file, bincode::config::standard())?;
+    let object = bincode::decode_from_std_read::<T, _, _>(&mut file, bincode::config::standard())
+        .context("decoding cache object")?;
     let object = Arc::new(object);
     let size = file.stream_position()? as usize; // this is an approximation mainly since varint is used in bincode