Function removeDataCommand

internal/controller/pgupgrade/jobs.go:269–301

Remove data job removeDataCommand returns an entrypoint that removes certain directories. We currently target the `pgdata/pg{old_version}` and `pgdata/pg{old_version}_wal` directories for removal.

(upgrade *v1beta1.PGUpgrade)

// We currently target the `pgdata/pg{old_version}` and `pgdata/pg{old_version}_wal`
// directories for removal.
func removeDataCommand(upgrade *v1beta1.PGUpgrade) []string {
	oldVersion := upgrade.Spec.FromPostgresVersion

	// Before removing the directories (both data and wal), we check that
	// the directory is not in use by running `pg_controldata` and making sure
	// the server state is "shut down in recovery"
	args := []string{fmt.Sprint(oldVersion)}
	script := strings.Join([]string{
		// Exit immediately when a pipeline or subshell exits non-zero or when expanding an unset variable.
		`shopt -so errexit nounset`,

		`declare -r data_volume='/pgdata' old_version="$1"`,
		`printf 'Removing PostgreSQL %s data...\n\n' "$@"`,
		`delete() (set -x && rm -rf -- "$@")`,

		`old_data="${data_volume}/pg${old_version}"`,
		`control=$(` + postgres.ShellPath(oldVersion) + ` && LC_ALL=C pg_controldata "${old_data}")`,
		`read -r state <<< "${control##*cluster state:}"`,

		// We expect exactly one state for a replica that has been stopped.
		//
		// https://git.postgresql.org/gitweb/?p=postgresql.git;hb=refs/tags/REL_10_0;f=src/bin/pg_controldata/pg_controldata.c#l55
		// https://git.postgresql.org/gitweb/?p=postgresql.git;hb=refs/tags/REL_17_0;f=src/bin/pg_controldata/pg_controldata.c#l58
		`[[ "${state}" == 'shut down in recovery' ]] || { printf >&2 'Unexpected state! %q\n' "${state}"; exit 1; }`,

		// "rm" does not follow symbolic links.
		// Delete the old data directory after subdirectories that contain versioned data.
		`delete "${old_data}/pg_wal/"`,
		`delete "${old_data}" && echo 'Success!'`,
	}, "\n")

	return append([]string{"bash", "-c", "--", script, "remove"}, args...)
}

// generateRemoveDataJob returns a Job that can remove the data
// on the given replica StatefulSet