`--mount` option problem for building Postgres image

[erfan-mehraban]

Expected Behavior

Running pgbench benchmark on PostgreSQL as a probe should be enough for docker-slim to create a minified image which can handle same load. Creating a database, filling it with some data and running some concurrent queries is what pgbench do.

---

Actual Behavior

But after building slim image some odd behavior appear:

• Postgres image (specially on alpine) isn't minified.
• docker-slim doesn't respect --mount and --exclude-mounts, generated image still has files in mounted volume location.
• Some log showing artifact sensor facing don't exist problem and missing in rawNames

---

Steps to Reproduce the Problem

docker-slim build \
    --target postgres:14.3-alpine \
    --env POSTGRES_HOST_AUTH_METHOD=trust \
    --show-clogs=true \
    --http-probe=false \
    --mount pgdata:/var/lib/postgresql/data/ \
    --exclude-mounts \
    --exec "pgbench -i -U postgres -s 10 postgres && pgbench -U postgres -c 10 -t 2000 postgres && psql -U postgres postgres -c 'DROP TABLE pgbench_accounts, pgbench_branches, pgbench_tellers, pgbench_history;'"

log file is attached.

for testing minified image run this docker-compose:

version: '3.3'
services:
  postgres:
    image: postgres.slim:latest
    environment:
      POSTGRES_HOST_AUTH_METHOD: trust
  tester:
    image: postgres:14.3
    entrypoint:
      - bash
      - -c
      - "sleep 3; pgbench -i -U postgres -h postgres -s 50 postgres && pgbench -U postgres -h postgres -c 30 -t 10000 postgres"

Postgres exits with this error:

PostgreSQL Database directory appears to contain a database; Skipping initialization
FATAL:  58P01: could not open directory "/usr/local/lib/postgresql": No such file or directory

---

Specifications

• Version: docker-slim version linux|Transformer|1.37.6|26a36c88a94c677efd734e874ba081dabb84a224|2022-04-23_06:03:56AM
• Platform: Ubuntu 18.04.6 LTS, docker-slim ran on host (not in a container)

[erfan-mehraban]

@kcq What is the process of checking issues in this repository? Is there any triage step to wait for?

It would be great if you help me to contribute better on this project.

[kcq]

Great issue @erfan-mehraban ! Thank you for sharing it and the repro info. It'll make it easier to root cause the problem. Give me a couple of days to review and I'll post an update

[erfan-mehraban]

@kcq

I would appreciate it if you could point me in the right direction to debug this issue.

[redthing1]

I have the same issue too lol

[kcq]

Trying to investigated additional adjacent issues with the setup, which is taking extra time... Respecting the --mount and --exclude-mount flags problem can be addressed on its own (i'll do that for the next release as an incremental improvement).