Fix bug if no instance_name/resource_name is given upload does not work

Fixes a bug that if an upload is attempted but no instance_name is
configured it will error out.

util/BUILD

@@ -143,6 +143,16 @@ rust_library(
     visibility = ["//visibility:public"],
 )
 
+rust_test(
+    name = "resource_info_test",
+    srcs = ["tests/resource_info_test.rs"],
+    deps = [
+        "//third_party:pretty_assertions",
+        "//third_party:tokio",
+        ":resource_info",
+    ],
+)
+
 rust_test(
     name = "fastcdc_test",
     srcs = ["tests/fastcdc_test.rs"],

util/resource_info.rs

@@ -24,35 +24,46 @@ pub struct ResourceInfo<'a> {
 
 impl<'a> ResourceInfo<'a> {
     pub fn new(resource_name: &'a str) -> Result<ResourceInfo<'a>, Error> {
-        let mut parts = resource_name.splitn(6, '/');
+        let mut parts = resource_name.splitn(6, '/').peekable();
         const ERROR_MSG: &str = concat!(
             "Expected resource_name to be of pattern ",
-            "'{instance_name}/uploads/{uuid}/blobs/{hash}/{size}' or ",
-            "'{instance_name}/blobs/{hash}/{size}'",
+            "'{?instance_name/}uploads/{uuid}/blobs/{hash}/{size}' or ",
+            "'{?instance_name/}blobs/{hash}/{size}'",
         );
-        let instance_name = &parts.next().err_tip(|| ERROR_MSG)?;
-        let mut blobs_or_uploads: &str = parts.next().err_tip(|| ERROR_MSG)?;
+
+        let mut instance_name = "";
+        let maybe_instance_name = parts.next().err_tip(|| ERROR_MSG)?;
+        let peek_next = parts.peek().err_tip(|| ERROR_MSG)?;
+        let blobs_or_uploads = if *peek_next == "uploads" || *peek_next == "blobs" {
+            instance_name = maybe_instance_name;
+            // We do have an instance_name, so set blobs_or_uploads to the peek_next and consume it.
+            parts.next().err_tip(|| ERROR_MSG)?
+        } else {
+            // We don't have an instance_name, so use our first item as blobs_or_uploads.
+            maybe_instance_name
+        };
         let mut uuid = None;
-        if &blobs_or_uploads == &"uploads" {
+        if blobs_or_uploads == "uploads" {
             uuid = Some(parts.next().err_tip(|| ERROR_MSG)?);
-            blobs_or_uploads = parts.next().err_tip(|| ERROR_MSG)?;
+            let blobs = parts.next().err_tip(|| ERROR_MSG)?;
+            error_if!(
+                blobs != "blobs",
+                "Expected resource_name to have 'blobs' here. Got: {}",
+                blobs_or_uploads
+            );
         }
 
-        error_if!(
-            &blobs_or_uploads != &"blobs",
-            "Element 2 or 4 of resource_name should have been 'blobs'. Got: {}",
-            blobs_or_uploads
-        );
-        let hash = &parts.next().err_tip(|| ERROR_MSG)?;
+        let hash = parts.next().err_tip(|| ERROR_MSG)?;
         let raw_digest_size = parts.next().err_tip(|| ERROR_MSG)?;
         let expected_size = raw_digest_size.parse::<usize>().err_tip(|| {
             format!(
                 "Digest size_bytes was not convertible to usize. Got: {}",
                 raw_digest_size
             )
         })?;
+
         Ok(ResourceInfo {
-            instance_name: instance_name,
+            instance_name,
             uuid,
             hash,
             expected_size,

util/tests/resource_info_test.rs

@@ -0,0 +1,73 @@
+// Copyright 2022 The Turbo Cache Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use resource_info::ResourceInfo;
+
+#[cfg(test)]
+mod resource_info_tests {
+    use super::*;
+    use pretty_assertions::assert_eq; // Must be declared in every module.
+
+    #[tokio::test]
+    async fn with_resource_name_blobs_test() -> Result<(), Box<dyn std::error::Error>> {
+        const RESOURCE_NAME: &str = "foo_bar/blobs/HASH-HERE/12345";
+        let resource_info = ResourceInfo::new(RESOURCE_NAME)?;
+
+        assert_eq!(resource_info.instance_name, "foo_bar");
+        assert_eq!(resource_info.uuid, None);
+        assert_eq!(resource_info.hash, "HASH-HERE");
+        assert_eq!(resource_info.expected_size, 12345);
+
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn with_resource_name_uploads_test() -> Result<(), Box<dyn std::error::Error>> {
+        const RESOURCE_NAME: &str = "foo_bar/uploads/UUID-HERE/blobs/HASH-HERE/12345";
+        let resource_info = ResourceInfo::new(RESOURCE_NAME)?;
+
+        assert_eq!(resource_info.instance_name, "foo_bar");
+        assert_eq!(resource_info.uuid, Some("UUID-HERE"));
+        assert_eq!(resource_info.hash, "HASH-HERE");
+        assert_eq!(resource_info.expected_size, 12345);
+
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn without_resource_name_blobs_test() -> Result<(), Box<dyn std::error::Error>> {
+        const RESOURCE_NAME: &str = "blobs/HASH-HERE/12345";
+        let resource_info = ResourceInfo::new(RESOURCE_NAME)?;
+
+        assert_eq!(resource_info.instance_name, "");
+        assert_eq!(resource_info.uuid, None);
+        assert_eq!(resource_info.hash, "HASH-HERE");
+        assert_eq!(resource_info.expected_size, 12345);
+
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn without_resource_name_uploads_test() -> Result<(), Box<dyn std::error::Error>> {
+        const RESOURCE_NAME: &str = "uploads/UUID-HERE/blobs/HASH-HERE/12345";
+        let resource_info = ResourceInfo::new(RESOURCE_NAME)?;
+
+        assert_eq!(resource_info.instance_name, "");
+        assert_eq!(resource_info.uuid, Some("UUID-HERE"));
+        assert_eq!(resource_info.hash, "HASH-HERE");
+        assert_eq!(resource_info.expected_size, 12345);
+
+        Ok(())
+    }
+}