Need help understanding the Firebase Storage CDN

Question

I'm building an audiobook app and have uploaded the audio files on Firebase Storage. My problem is that I experience different performances in San Francisco vs Toronto. I am under the impression that Firebase Storage has built-in CDN. if so, Do I need to enable it somewhere? if not, how do I add GCP CDN to my Firebase Storage files behind Firebase Auth??

Checking the domain storage.googleapis.com which is where my Firebase Storage files are hosted shows that it is using the Google CDN.

Here are the response headers for one of my public audio file request:

accept-ranges: bytes
alt-svc: quic=":443"; ma=2592000; v="46,44,43,39"
cache-control: public, max-age=3600
content-disposition: inline; filename*=utf-8''G4PT7dPIyEuIz74BtTmm_FallIsTheLastSeasonOfTheYear.mp3
content-length: 3162637
content-type: audio/mp3
date: Tue, 30 Apr 2019 17:13:34 GMT
etag: "98013599e6f108a0edeeaac7c8b2bb45"
expires: Tue, 30 Apr 2019 18:13:34 GMT
last-modified: Mon, 08 Apr 2019 17:59:58 GMT
server: UploadServer
status: 200
x-goog-generation: 1554746398034230
x-goog-hash: crc32c=TKSAfA==, md5=mAE1mebxCKDt7qrHyLK7RQ==
x-goog-meta-firebasestoragedownloadtokens: da578546-c265-4f06-ae11-6273a7812bf2
x-goog-metageneration: 2
x-goog-storage-class: STANDARD
x-goog-stored-content-encoding: identity
x-goog-stored-content-length: 3162637
x-guploader-uploadid: AEnB2UqdvgzkJMC0yHJkGbr-K5cWWbXK5I2j6NLtd4NwG1G9swIhhp1QC8G25JUK4LItZID0IxuYhhLta3YImMTtzbKkr5vcEQ

Answer 1

I reached out to Firebase Support and here is the answer I got:

Regarding the CDN question, the short answer is no, Cloud Storage has no built-in CDN; the less short answer is: when your Cloud Storage is "multi-regional", it means that "hot content" (frequently accessed content) is available on different locations, but that is limited to multi-regional locations, and it applies only to the "jurisdiction" of the location, so, for example, if your project is in "us-central", then your multi-regional Storage will be stored only in the US data centers, so when accessed from Toronto, it will be served from the nearest US datacenter.

Now, there are ways to add a CDN to Cloud Storage content; I found this small guide using Google CDN: https://medium.com/@marco_37432/create-a-custom-domain-cdn-with-google-beta-7ad9531dfbae

Another use that I have seen is creating a static website with Cloud Storage and adding on top another CDN provider, like CloudFlare. You can see more details in this links:

https://cloudplatform.googleblog.com/2015/09/push-google-cloud-origin-content-out-to-users.html https://cloud.google.com/interconnect/docs/how-to/cdn-interconnect

Answer 2

This is classic Google.

You can upload the images to the Storage, but you can't serve them and it's not a CDN.

Great.