Avoid HTTP 400 Bad Request by configuring request header limits

[tachylatus]

Users sometimes experience HTTP 400 due to request headers exceeding server limit, typically when the cookie grows beyond 8190 bytes.

Specifically when using OIDC, it has been suggested, in issue #492, to adjust OIDCStateMaxNumberOfCookies.

Instead, I propose we make it easier to configure and increase server limits for both apache and per-user nginx (pun).

Currently, you can do the following to increase the limits from 8k to 32k:

• In ood_portal.yaml, add the following entry to the ssl: list: - 'LimitRequestFieldSize 32766'
• Create an app configuration e.g. /var/lib/ondemand-nginx/config/apps/sys/nginx_server_settings.conf containing the line large_client_header_buffers 4 32k;, which will then be auto-included in the server context of generated pun configs.

[tachylatus]

Also related:

• Cookie length too long results in Bad Request #814
• https://discourse.openondemand.org/t/400-bad-request/3292

[johrstrom]

Yea I think we could add a config for LimitRequestFieldSize.