Persistent volume for Blockscout's Postgres can crash on startup on Macs

[steezeburger]

I will sometimes get an error when Blockscout's Postgres is starting up related to data already existing. This blocks Blockscout from starting.

| The database cluster will be initialized with locale "en_US.utf8".                                                                                                                             │
│ The default database encoding has accordingly been set to "UTF8".                                                                                                                              │
│ The default text search configuration will be set to "english".                                                                                                                                │
│                                                                                                                                                                                                │
│ Data page checksums are disabled.                                                                                                                                                              │
│                                                                                                                                                                                                │
│ initdb: error: directory "/var/lib/postgresql/data" exists but is not empty                                                                                                                    │
│ If you want to create a new database system, either remove or empty                                                                                                                            │
│ the directory "/var/lib/postgresql/data" or run initdb                                                                                                                                         │
│ with an argument other than "/var/lib/postgresql/data".

[steezeburger]

postgres image entrypoint https://github.com/docker-library/postgres/blob/master/docker-entrypoint.sh

[steezeburger]

I think it's not finding PG_VERSION for some reason
https://github.com/docker-library/postgres/blob/master/docker-entrypoint.sh#L229C19-L229C29

[steezeburger]

Found the issue!

MacOS runs a periodic cleaner on the temp directory that deletes files that haven't been used in 3 days. It only deletes files but not directories, so postgres was seeing that the data directory existed but the check for PG_VERSION failed.