We got something working, whether this is correct or not we don’t know, so if someone can confirm we would be grateful.
The first steps are to go to:
PlayFab Game Manager → Settings → OpenID Connect → New connection
Add an OpenID connection using the same client Id and secret used for logging into the EOS online subsystem. The “Issuer” seems to only work when set to “https://api.epicgames.dev/epic/oauth/v1”. The EOS docs seem to imply that OAuth v2 should be used although that didn’t work for us.
Then we used the GetAuthToken function on the EOS online subsystem identity interface and passed that as the ID token into the PlayFab function LoginWithOpenIdConnect.
When that completes the user is then authenticated with PlayFab and you can see your new user in:
PlayFab Game Manager → Players
We had to use a bit of trial and error to get this working as we couldn’t find any good docs to explain any of these steps. So any feedback on whether what we are doing is correct or not would be appreciated.