Gracefully handle database connection unavailable

Describe the bug When the database connection to the backend storage is unavailable (tested with postgres), the server keeps on crashing instead of gracefully reporting database connection issues.

To Reproduce Steps to reproduce the behavior:

1. Stop your database server (postgres)
2. Start etherpad
3. Visit some page that needs the database connection (any pad should do, in my case, also triggered when viewing /admin/plugins
4. See error

Expected behavior Graceful fallback to display some frontend error message, but keep running despite this lack of database connectivity.

Actual behaviour

[2020-11-12 22:13:05.858] [ERROR] console - error: column "value" is of type jsonb but expression is of type text
    at Parser.parseErrorMessage (/home/etherpad/etherpad-lite/src/node_modules/pg-protocol/dist/parser.js:278:15)
    at Parser.handlePacket (/home/etherpad/etherpad-lite/src/node_modules/pg-protocol/dist/parser.js:126:29)
    at Parser.parse (/home/etherpad/etherpad-lite/src/node_modules/pg-protocol/dist/parser.js:39:38)
    at Socket.stream.on (/home/etherpad/etherpad-lite/src/node_modules/pg-protocol/dist/index.js:8:42)
    at Socket.emit (events.js:198:13)
    at Socket.EventEmitter.emit (domain.js:448:20)
    at addChunk (_stream_readable.js:288:12)
    at readableAddChunk (_stream_readable.js:269:11)
    at Socket.Readable.push (_stream_readable.js:224:10)
    at TCP.onStreamRead [as onread] (internal/stream_base_commons.js:94:17)
[2020-11-12 22:13:05.858] [INFO] console - Stopping Etherpad...
[2020-11-12 22:13:05.876] [ERROR] console - TypeError: Cannot read property 'name' of null
    at Client._handleParseComplete (/home/etherpad/etherpad-lite/src/node_modules/pg/lib/client.js:358:26)
    at Connection.emit (events.js:198:13)
    at Connection.EventEmitter.emit (domain.js:448:20)
    at parse (/home/etherpad/etherpad-lite/src/node_modules/pg/lib/connection.js:109:12)
    at Parser.parse (/home/etherpad/etherpad-lite/src/node_modules/pg-protocol/dist/parser.js:40:17)
    at Socket.stream.on (/home/etherpad/etherpad-lite/src/node_modules/pg-protocol/dist/index.js:8:42)
    at Socket.emit (events.js:198:13)
    at Socket.EventEmitter.emit (domain.js:448:20)
    at addChunk (_stream_readable.js:288:12)
    at readableAddChunk (_stream_readable.js:269:11)

Additional context

Etherpad version
Version number: 1.8.6
Latest available version: 1.8.6
Git sha: 6a8563e

[JohnMcLear]

Oh check the reverted commits. There was a bad pg commit a while back that was related I think…

[BenBE]

After conversion to text everything seems to work:

ALTER TABLE storage ALTER COLUMN value TYPE text USING value::text;