Summary:
Ref T4571. If we fail to connect to the master, automatically try to degrade into a temporary read-only mode ("UNREACHABLE") for the remainder of the request, if possible.
If the request was something like "load the homepage", that'll work fine. If it was something like "submit a comment", there's nothing we can do and we just have to fail.
Detecting this condition imposes a performance penalty: every request checks the connection and gives the database a long time to respond, since we don't want to drop writes unless we have to. So the degraded mode works, but it's really slow, and may perpetuate the problem if the root issue is load-related.
This lays the groundwork for improving this case by degrading futher into a "SEVERED" mode which will persist across requests. In the future, if several requests in a short period of time fail, we'll sever the database host and refuse to try to connect to it for a little while, connecting directly to replicas instead (basically, we're "health checking" the master, like a load balancer would health check a web application server). This will give us a better (much faster) degraded mode in a major service disruption, and reduce load on the master if the root cause is load-related, giving it a better chance of recovering on its own.
Test Plan:
- Disabled master in config by changing the host/username, got degraded automatically to UNREACAHBLE mode immediately.
- Faked full SEVERED mode, requests hit replicas and put me in the mode properly.
- Made stuff work, hit some good pages.
- Hit some non-cluster pages.
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T4571
Differential Revision: https://secure.phabricator.com/D15674
Summary: Ref T4571. If `cluster.databases` is configured but only has replicas, implicitly drop to read-only mode and send writes to a replica.
Test Plan:
- Disabled the `master`, saw Phabricator automatically degrade into read-only mode against replicas.
- (Also tested: explicit read-only mode, non-cluster mode, properly configured cluster mode).
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T4571
Differential Revision: https://secure.phabricator.com/D15672
Summary:
Ref T4571. Allows users to click the "read-only mode" notification to get more information about why an install is in read-only mode.
Installs can be in this mode for several reasons (explicit administrative action, no masters defined, no masters reachable), and it's useful to be able to tell the difference.
Test Plan: {F1212930}
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T4571
Differential Revision: https://secure.phabricator.com/D15671
Summary:
Ref T10262. This removes one-time tokens and makes file data responses always-cacheable (for 30 days).
The URI will stop working once any attached object changes its view policy, or the file view policy itself changes.
Files with `canCDN` (totally public data like profile images, CSS, JS, etc) use "cache-control: public" so they can be CDN'd.
Files without `canCDN` use "cache-control: private" so they won't be cached by the CDN. They could still be cached by a misbehaving local cache, but if you don't want your users seeing one anothers' secret files you should configure your local network properly.
Our "Cache-Control" headers were also from 1999 or something, update them to be more modern/sane. I can't find any evidence that any browser has done the wrong thing with this simpler ruleset in the last ~10 years.
Test Plan:
- Configured alternate file domain.
- Viewed site: stuff worked.
- Accessed a file on primary domain, got redirected to alternate domain.
- Verified proper cache headers for `canCDN` (public) and non-`canCDN` (private) files.
- Uploaded a file to a task, edited task policy, verified it scrambled the old URI.
- Reloaded task, new URI generated transparently.
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T10262
Differential Revision: https://secure.phabricator.com/D15642
Summary: Ref T5179. Ref T4045. Ref T832. We can now write non-utf8 hunks into the database, so try to do more reasonable things with them in the UI.
Test Plan: (See screenshots...)
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: epriestley
Maniphest Tasks: T832, T4045, T5179
Differential Revision: https://secure.phabricator.com/D9294
Summary:
Fixes T4610. Open to suggestions, etc., if there's anything I'm missing.
Also:
- Moves these "system" endpoints into a real application.
- Makes `isUnlisted()` work a little more consistently.
Test Plan: Accessed `/robots.txt`, `/status/` and `/debug/`.
Reviewers: chad, btrahan
Reviewed By: btrahan
Subscribers: aran, epriestley
Maniphest Tasks: T4610
Differential Revision: https://secure.phabricator.com/D8532
