nixos/firefox-syncserver: add PostgreSQL backend support

[Titaniumtown]

Added support to the firefox-syncserver module for PostgreSQL databases. The upstream project has support for it, but the module did not. I also modified the actual firefox-syncserver package to allow the PostgreSQL feature flag to be set by changing the target database backend.

I needed to bump the version of the underlying package as the version currently shipping doesn't contain PostgreSQL support.

One concern I have is about the feature flag handling, should we just compile for both mysql and PostgreSQL? Right now I have it so it's either-or and it's determined by a feature flag.

LLMs used: Claude Opus 4.6 via opencode

Things done

• Built on platform:
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• Tested, as applicable:
  • NixOS tests in nixos/tests.
  • Package tests at passthru.tests.
  • Tests in lib/tests or pkgs/test for functions and "core" functionality.
• Ran nixpkgs-review on this PR. See nixpkgs-review usage.
• Tested basic functionality of all binary files, usually in ./result/bin/.
• Nixpkgs Release Notes
  • Package update: when the change is major or breaking.
• NixOS Release Notes
  • Module addition: when adding a new NixOS module.
  • Module update: when the change is significant.
• Fits CONTRIBUTING.md, pkgs/README.md, maintainers/README.md and other READMEs.

[ntninja]

Since my independently developed version #507460 of this change was deemed a duplicate of this, I gave your version a review with things that are better in my version (some is better in yours).

should we just compile for both mysql and PostgreSQL?

That is not possible, the source code is written in such a way that if you compile for both you’ll get a symbol clash.

For keeping having the PostgreSQL feature on SyncServer not enable MySQL on TokenServer, I have a small patch:
https://github.com/ntninja/nixpkgs/blob/8f8c170c8628ca864d41eb80078147f828cc37db/pkgs/by-name/sy/syncstorage-rs/01-syncserver-tokenserver-postgres-db.patch

Upstream is mostly happy with it, other than it breaking their CI script assumptions, will update soon hopefully:
mozilla-services/syncstorage-rs#2194

[Titaniumtown]

Thanks for all the feedback @mweinelt and @ntninja, I will try and work through this today :)

[Titaniumtown]

Thank you for your further review @mweinelt, I'm on it!

[Titaniumtown]

Rebased.

[mweinelt]

I'm terribly sorry for the long wait. I want postgres support so much, but couldn't find the motivation to get to this PR quickly.

[Titaniumtown]

@mweinelt No need to apologize. Thanks for the reviews, I will get to them soon!

[Titaniumtown]

rebased

[mweinelt]

Both the mysql and the postgresql NixOS tests time out for me.

!!! Traceback (most recent call last):
!!!   File "<string>", line 3, in <module>
!!!     machine.wait_until_succeeds("curl -s http://127.0.0.1:5000/__heartbeat__ | jq -e '.database == \"Ok\" and .status == \"OK\"'")
!!! 
!!! RequestedAssertionFailed: action timed out after 900.60 seconds (timeout=900)

[Titaniumtown]

Weird, worked on my machine, maybe the rebase broke it. I will investigate when I get home.

[mweinelt]

diff --git a/nixos/tests/firefox-syncserver.nix b/nixos/tests/firefox-syncserver.nix
index 89110928d1e9..2e03d8cd8f9b 100644
--- a/nixos/tests/firefox-syncserver.nix
+++ b/nixos/tests/firefox-syncserver.nix
@@ -9,7 +9,7 @@ let
       {
         name = "firefox-syncserver-${name}";
 
-        nodes.machine =
+        containers.machine =
           { pkgs, ... }:
           lib.mkMerge [
             {
@@ -43,7 +43,7 @@ let
         testScript = ''
           machine.wait_for_unit("multi-user.target")
           machine.wait_until_succeeds("systemctl is-active firefox-syncserver.service", timeout=120)
-          machine.wait_until_succeeds("curl -s http://127.0.0.1:5000/__heartbeat__ | jq -e '.database == \"Ok\" and .status == \"OK\"'")
+          machine.wait_until_succeeds("curl -s http://127.0.0.1:5000/__heartbeat__ | jq -e '.database == \"Ok\" and .status == \"Ok\"'")
         '';
       }
     );

nspawn container tests and the test fix