[BUG] When trying to delete a config, the captcha can not be generated

[RobHofmann]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

When trying to delete a configuration, it will throw the following error in the docker logs:

fail: Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware[1]
      An unhandled exception has occurred while executing the request.
      System.Exception: No usable font found
         at Duplicati.WebserverCore.Services.CaptchaService.CaptchaUtil.CreateCaptcha(String answer, Size size, Single fontsize)
         at Duplicati.WebserverCore.Services.CaptchaService.GetCaptchaImage(String token)
         at Duplicati.WebserverCore.Endpoints.V1.Captcha.<>c.<Map>b__0_0(ICaptchaProvider captchaProvider, IHttpContextAccessor httpContextAccessor, String token, CancellationToken ct)
         at lambda_method205(Closure, EndpointFilterInvocationContext)
         at Duplicati.WebserverCore.Middlewares.HostnameFilter.InvokeAsync(EndpointFilterInvocationContext context, EndpointFilterDelegate next)
         at Duplicati.WebserverCore.Middlewares.LanguageFilter.InvokeAsync(EndpointFilterInvocationContext context, EndpointFilterDelegate next)
         at Microsoft.AspNetCore.Http.RequestDelegateFactory.<ExecuteValueTaskOfObject>g__ExecuteAwaited|129_0(ValueTask`1 valueTask, HttpContext httpContext, JsonTypeInfo`1 jsonTypeInfo)
         at Duplicati.WebserverCore.Middlewares.WebsocketExtensions.<>c__DisplayClass0_0.<<UseNotifications>b__0>d.MoveNext()
      --- End of stack trace from previous location ---
         at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddlewareImpl.<Invoke>g__Awaited|10_0(ExceptionHandlerMiddlewareImpl middleware, HttpContext context, Task task)

Expected Behavior

No response

Steps To Reproduce

1. Start duplicati docker
2. Create configuration
3. Delete configuration
4. Captcha won't be generated & you are unable to delete the config.

Environment

- OS:Ubuntu 20.04.6 LTS (GNU/Linux 5.4.0-193-generic x86_64)
- How docker service was installed: docker run command

CPU architecture

x86-64

Docker creation

docker network create --subnet <redacted>/24 uplink-duplicati || true
docker run --name=duplicati --cpus=4 --memory=1GB -d --restart=unless-stopped --net=uplink-duplicati -v /<redacted>/Duplicati/config:/config -v /<redacted>:/docker:ro -v /<redacted>:/hofpudcr102:ro -v /<redacted>:/hofpudcr103:ro -v /<redacted>:/hofpudcr104:ro -v /nfs/media:/media:ro -v /nfs/backup:/backup:ro -e PGID=0 -e PUID=0 linuxserver/duplicati:latest
docker network connect traefik-internal duplicati || true

Container logs

[migrations] started
[migrations] no migrations found
───────────────────────────────────────

      ██╗     ███████╗██╗ ██████╗
      ██║     ██╔════╝██║██╔═══██╗
      ██║     ███████╗██║██║   ██║
      ██║     ╚════██║██║██║   ██║
      ███████╗███████║██║╚██████╔╝
      ╚══════╝╚══════╝╚═╝ ╚═════╝

   Brought to you by linuxserver.io
───────────────────────────────────────

To support LSIO projects visit:
https://www.linuxserver.io/donate/

───────────────────────────────────────
GID/UID
───────────────────────────────────────

User UID:    0
User GID:    0
───────────────────────────────────────
Linuxserver.io version: v2.1.0.2_beta_2024-11-29-ls225
Build-date: 2024-11-29T16:39:04+00:00
───────────────────────────────────────

***      Missing encryption key, unable to encrypt your settings database     ***
*** Please set a value for SETTINGS_ENCRYPTION_KEY and recreate the container ***
[custom-init] No custom files found, skipping...
Inside getter
Server has started and is listening on port 8200
Connection to localhost (::1) 8200 port [tcp/*] succeeded!
[ls.io-init] done.
fail: Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware[1]
      An unhandled exception has occurred while executing the request.
      System.Exception: No usable font found
         at Duplicati.WebserverCore.Services.CaptchaService.CaptchaUtil.CreateCaptcha(String answer, Size size, Single fontsize)
         at Duplicati.WebserverCore.Services.CaptchaService.GetCaptchaImage(String token)
         at Duplicati.WebserverCore.Endpoints.V1.Captcha.<>c.<Map>b__0_0(ICaptchaProvider captchaProvider, IHttpContextAccessor httpContextAccessor, String token, CancellationToken ct)
         at lambda_method205(Closure, EndpointFilterInvocationContext)
         at Duplicati.WebserverCore.Middlewares.HostnameFilter.InvokeAsync(EndpointFilterInvocationContext context, EndpointFilterDelegate next)
         at Duplicati.WebserverCore.Middlewares.LanguageFilter.InvokeAsync(EndpointFilterInvocationContext context, EndpointFilterDelegate next)
         at Microsoft.AspNetCore.Http.RequestDelegateFactory.<ExecuteValueTaskOfObject>g__ExecuteAwaited|129_0(ValueTask`1 valueTask, HttpContext httpContext, JsonTypeInfo`1 jsonTypeInfo)
         at Duplicati.WebserverCore.Middlewares.WebsocketExtensions.<>c__DisplayClass0_0.<<UseNotifications>b__0>d.MoveNext()
      --- End of stack trace from previous location ---
         at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddlewareImpl.<Invoke>g__Awaited|10_0(ExceptionHandlerMiddlewareImpl middleware, HttpContext context, Task task)

[github-actions]

Thanks for opening your first issue here! Be sure to follow the relevant issue templates, or risk having this issue marked as invalid.

[thespad]

Can you exec into the container and try running:

echo ttf-mscorefonts-installer msttcorefonts/accepted-mscorefonts-eula select true | debconf-set-selections
apt-get update && apt-get install -y --no-install-recommends ttf-mscorefonts-installer

And then try again. It looks like it's after one of these fonts https://github.com/duplicati/duplicati/blob/e3e814a09fee33ed0d26a3662bace449eabcc4af/Duplicati/WebserverCore/Services/CaptchaService.cs#L25-L26

[RobHofmann]

yes this fixes it!

[RobHofmann]

Can we incorporate this into the linuxserver/duplicati image by default? :)

[thespad]

Yes, I'll sort out a PR to add the fonts to the image.