Make SQLBlob overwrite on put rather than ignoring

Summary:
We want to end up with two `put` behaviours - overwrite and do not overwrite.

Currently, SQLBlob only implements the latter, but some users assume that `put` always overwrites. Change to match Manifold

Reviewed By: aslpavel

Differential Revision: D24079501

fbshipit-source-id: f75cac81acf874337c38f82597aae645c41a319b

eden/mononoke/blobstore/sqlblob/src/store.rs

@@ -76,6 +76,16 @@ queries! {
         ) VALUES {values}"
     }
 
+    write UpdateData(id: &str, ctime: i64, chunk_id: &str, chunk_count: u32, chunking_method: ChunkingMethod) {
+        none,
+        "UPDATE data SET
+            creation_time = {ctime}
+            , chunk_id = {chunk_id}
+            , chunk_count = {chunk_count}
+            , chunking_method = {chunking_method}
+        WHERE id = {id}"
+    }
+
     write InsertChunk(values: (id: &str, chunk_num: u32, value: &[u8])) {
         insert_or_ignore,
         "{insert_or_ignore} INTO chunk (
@@ -177,12 +187,24 @@ impl DataSqlStore {
 
         self.delay.delay(shard_id).await;
 
-        InsertData::query(
+        let res = InsertData::query(
             &self.write_connection[shard_id],
             &[(&key, &ctime, &chunk_id, &chunk_count, &chunking_method)],
         )
         .compat()
         .await?;
+        if res.affected_rows() == 0 {
+            UpdateData::query(
+                &self.write_connection[shard_id],
+                &key,
+                &ctime,
+                &chunk_id,
+                &chunk_count,
+                &chunking_method,
+            )
+            .compat()
+            .await?;
+        }
         Ok(())
     }
 

eden/mononoke/blobstore/sqlblob/src/tests.rs

@@ -77,6 +77,39 @@ async fn double_put(fb: FacebookInit) {
     );
 }
 
+#[fbinit::compat_test]
+async fn overwrite(fb: FacebookInit) -> Result<()> {
+    let ctx = CoreContext::test_mock(fb);
+    // Generate unique keys.
+    let suffix: String = thread_rng().sample_iter(&Alphanumeric).take(10).collect();
+    let key = format!("manifoldblob_test_{}", suffix);
+
+    let bs = Arc::new(Sqlblob::with_sqlite_in_memory().unwrap());
+
+    let mut bytes_1 = [0u8; 64];
+    thread_rng().fill_bytes(&mut bytes_1);
+    let mut bytes_2 = [0u8; 32];
+    thread_rng().fill_bytes(&mut bytes_2);
+
+    let blobstore_bytes_1 = BlobstoreBytes::from_bytes(Bytes::copy_from_slice(&bytes_1));
+    let blobstore_bytes_2 = BlobstoreBytes::from_bytes(Bytes::copy_from_slice(&bytes_2));
+
+    // Write a fresh blob
+    bs.put(ctx.clone(), key.clone(), blobstore_bytes_1.clone())
+        .await?;
+    // Overwrite it
+    bs.put(ctx.clone(), key.clone(), blobstore_bytes_2.clone())
+        .await?;
+
+    assert_eq!(
+        bs.get(ctx.clone(), key.clone())
+            .await?
+            .map(|get| get.into_bytes()),
+        Some(blobstore_bytes_2),
+    );
+    Ok(())
+}
+
 #[fbinit::compat_test]
 async fn dedup(fb: FacebookInit) {
     let ctx = CoreContext::test_mock(fb);