Cannot use the "postgresql-start" hooks with config maps

[nmasse-itix]

What I'm trying to achieve

• I want to deploy a postgres instance and have this instance prepared with some SQL statements (CREATE TABLE ...).
• I need to provision this postgres instance directly from the oc new-app command, without creating a GIT repository and going through the S2I build.

Steps to reproduce

Deploy a postgres instance:

oc new-app --name=postgresql --template=postgresql-persistent

Provision the start hook script

cat <<EOF > start.sh
echo ">>> Starting database schema creation"
echo "Here I would call 'psql bla bla bla'..."
echo "<<< Finished database schema creation"
EOF
oc create configmap postgresql-init --from-file=start.sh

Mount it on /opt/app-root/src/postgresql-start:

oc set volume dc/postgresql --add -t configmap --configmap-name=postgresql-init -m /opt/app-root/src/postgresql-start --name postgresql-init

Expected behavior

$ oc logs dc/postgresql

waiting for server to start....LOG:  redirecting log output to logging collector process
HINT:  Future log output will appear in directory "pg_log".
 done
server started
/var/run/postgresql:5432 - accepting connections
=> sourcing /usr/share/container-scripts/postgresql/start/set_passwords.sh ...
ALTER ROLE
=> sourcing /opt/app-root/src/postgresql-start/start.sh ...
>>> Starting database schema creation
Here I would call 'psql bla bla bla'...
<<< Finished database schema creation
waiting for server to shut down.... done
server stopped
Starting server...
LOG:  redirecting log output to logging collector process
HINT:  Future log output will appear in directory "pg_log".

Current behavior

$ oc logs dc/postgresql

waiting for server to start....LOG:  redirecting log output to logging collector process
HINT:  Future log output will appear in directory "pg_log".
 done
server started
/var/run/postgresql:5432 - accepting connections
=> sourcing /usr/share/container-scripts/postgresql/start/set_passwords.sh ...
ALTER ROLE
waiting for server to shut down.... done
server stopped
Starting server...
LOG:  redirecting log output to logging collector process
HINT:  Future log output will appear in directory "pg_log".

=> My start hook script is not loaded

Troubleshooting

In the container, I can see that my configmap has been correctly mounted:

$ ls /opt/app-root/src/postgresql-start/
start.sh

But the call to process_extending_files does not include my script:

$ . /usr/share/container-scripts/postgresql/common.sh

$ process_extending_files "${APP_DATA}/src/postgresql-start" "${CONTAINER_SCRIPTS_PATH}/start"
=> sourcing /usr/share/container-scripts/postgresql/start/set_passwords.sh ...

The call to get_matched_files does not include my script either:

$ get_matched_files '*.sh'  "${APP_DATA}/src/postgresql-start" "${CONTAINER_SCRIPTS_PATH}/start" | sort -u
set_passwords.sh

After further investigation, it appears that the configmap creates symlinks instead of regular files:

$ ls /opt/app-root/src/postgresql-start/ -la
total 4
drwxrwsrwx. 3 root     1000770000 4096 Nov 15 18:19 .
drwxrwxr-x. 1 postgres root         41 Nov 15 18:10 ..
drwxr-sr-x. 2 root     1000770000  234 Nov 15 18:19 ..2019_11_15_18_19_11.168320828
lrwxrwxrwx. 1 root     1000770000   31 Nov 15 18:19 ..data -> ..2019_11_15_18_19_11.168320828
lrwxrwxrwx. 1 root     root         15 Nov 15 18:10 start.sh -> ..data/start.sh

start.sh is a symlink to the proper file:

$ cat /opt/app-root/src/postgresql-start/start.sh
echo ">>> Starting database schema creation"
echo "Here I would call 'psql bla bla bla'..."
echo "<<< Finished database schema creation"

And the find command in the get_matched_files function in common.sh is missing the -L switch to follow symlinks. Hence, the test -type f leads to false in my case.

Resolution

Add the -L switch to the find command in the get_matched_files function in common.sh:

# get_matched_files PATTERN DIR [DIR ...]
# ---------------------------------------
# Print all basenames for files matching PATTERN in DIRs.
get_matched_files ()
{
  local pattern=$1 dir
  shift
  for dir; do
    test -d "$dir" || continue
    find -L "$dir" -maxdepth 1 -type f -name "$pattern" -printf "%f\n"
  done
}

And then it works:

$ get_matched_files '*.sh'  "${APP_DATA}/src/postgresql-start" "${CONTAINER_SCRIPTS_PATH}/start" | sort -u
set_passwords.sh
start.sh

$ process_extending_files "${APP_DATA}/src/postgresql-start" "${CONTAINER_SCRIPTS_PATH}/start"
=> sourcing /usr/share/container-scripts/postgresql/start/set_passwords.sh ...
=> sourcing /opt/app-root/src/postgresql-start/start.sh ...
>>> Starting database schema creation
Here I would call 'psql bla bla bla'...
<<< Finished database schema creation

[pkubatrh]

Hi @nmasse-itix, thanks for the thorough report! Unfortunately I have to close it as duplicate of #325 but followed up with a WIP PR #352