postgresql.yaml: port dry-run fixes (bugs 1,2,4,5) - $$(...) escaping, ETCD3_HOSTS, post_init_wrapper.sh SUPERUSER role fix

postgresql/postgresql.yaml

@@ -10,6 +10,47 @@
 # read secrets from /run/secrets and export them as the plain env vars
 # Spilo's configure_spilo.py actually expects, before invoking the image's
 # real entrypoint chain (/launch.sh init).
+#
+# NOTE: command: blocks use $$(...) not $(...) — Compose's own variable
+# interpolation parses $( as an attempted ${VAR} reference and fails with
+# "invalid interpolation format" / "you may need to escape any $ with
+# another $". $$ escapes to a literal $ for the shell at runtime. This
+# applies uniformly to EVERY literal $ character anywhere in a command:
+# block, including inside heredocs and nested quoting — Compose scans the
+# raw text before any shell/heredoc logic ever runs, so quoting context
+# doesn't exempt anything from this escaping requirement. (Confirmed the
+# hard way in the pgha-test dry run — see "ADR-0001 Dry-Run Debugging Log"
+# note — this file originally had the unescaped $(...) bug.)
+#
+# NOTE: ETCD3_HOSTS not ETCD_HOSTS — confirmed against zalando/spilo
+# configure_spilo.py: PATRONI_DCS includes both "etcd" (legacy v2 API,
+# python-etcd client) and "etcd3" (v3 API, python-etcd3 client) as
+# distinct DCS backends selected by env var prefix. Our etcd containers
+# (v3.5.9) have the v2 API disabled by default, so ETCD_HOSTS causes
+# Patroni to hit /v2 endpoints that 404. ETCD3_HOSTS selects the correct
+# v3-API client. (Also originally wrong in this file — fixed after dry run.)
+#
+# NOTE: patroni-0/patroni-1 override bootstrap.post_init via
+# SPILO_CONFIGURATION (Spilo's documented, supported mechanism for
+# overriding any generated Patroni config — configure_spilo.py deep-merges
+# user-supplied SPILO_CONFIGURATION on top of its own generated config).
+# This is needed because Spilo's own /scripts/post_init.sh hardcodes
+# "ALTER VIEW ... OWNER TO postgres" with no way to parameterize that role
+# name via env vars. Since our superuser is PGUSER_SUPERUSER=PGadmin (to
+# match production), there is no role literally named "postgres" in the
+# cloned data, so Spilo's unmodified script fails with
+# 'ERROR: role "postgres" does not exist'. The override points
+# bootstrap.post_init at our own wrapper script instead, which creates a
+# harmless, idempotent "postgres" role (WITH SUPERUSER NOLOGIN — SUPERUSER
+# is required because Spilo's own _zmon_schema.dump does
+# "SET ROLE TO postgres; CREATE EXTENSION plpython3u", which needs real
+# superuser privileges, not just role existence; NOLOGIN means it can never
+# be used to establish a real connection, so this carries no security
+# exposure), then execs Spilo's real, UNMODIFIED post_init.sh with all
+# original arguments passed through — Zalando's script itself is never
+# patched or forked. Both fixes (role existence + SUPERUSER) were found
+# and validated end-to-end in the pgha-test dry run before being ported
+# here — see the dry-run debugging note for full detail.
 # ─────────────────────────────────────────────────────────────────────────
 version: "3.6"
 
@@ -88,7 +129,9 @@ services:
   # ── Patroni / Spilo data replicas (2 total, per user constraint) ────────
   # Image tag pinned to 4.0-p3 (Zalando postgres-operator's own referenced
   # default at time of writing) — re-verify against current releases
-  # before actual deploy, as patch tags move.
+  # before actual deploy, as patch tags move. Decision (2026-07-30): staying
+  # on PostgreSQL 17 / this Spilo line for now; PG18 deferred as a separate
+  # future project pending app-compatibility checks. See ADR-0001 notes.
   patroni-0:
     image: ghcr.io/zalando/spilo-17:4.0-p3
     hostname: patroni-0
@@ -96,17 +139,28 @@ services:
       - /bin/sh
       - -c
       - |
-        export PGPASSWORD_SUPERUSER="$(cat /run/secrets/postgresql_password)"
+        export PGPASSWORD_SUPERUSER="$$(cat /run/secrets/postgresql_password)"
-        export PGPASSWORD_STANDBY="$(cat /run/secrets/postgresql_replication_password)"
+        export PGPASSWORD_STANDBY="$$(cat /run/secrets/postgresql_replication_password)"
-        export PATRONI_RESTAPI_PASSWORD="$(cat /run/secrets/postgresql_patroni_password)"
+        export PATRONI_RESTAPI_PASSWORD="$$(cat /run/secrets/postgresql_patroni_password)"
+        mkdir -p /scripts
+        cat > /scripts/post_init_wrapper.sh <<'WRAP'
+        #!/bin/bash
+        set -e
+        psql -d "$$2" -v ON_ERROR_STOP=1 -c 'DO $$do$$ BEGIN IF NOT EXISTS (SELECT 1 FROM pg_catalog.pg_roles WHERE rolname = $$x$$postgres$$x$$) THEN CREATE ROLE postgres WITH SUPERUSER NOLOGIN; END IF; END $$do$$;'
+        exec /scripts/post_init.sh "$$@"
+        WRAP
+        chmod +x /scripts/post_init_wrapper.sh
         exec /bin/sh /launch.sh init
     environment:
       SCOPE: postgres-ha
       PATRONI_NAME: patroni-0
-      ETCD_HOSTS: '"etcd-1:2379","etcd-2:2379","etcd-3:2379"'
+      ETCD3_HOSTS: '"etcd-1:2379","etcd-2:2379","etcd-3:2379"'
       PGUSER_STANDBY: standby
       PATRONI_RESTAPI_USERNAME: patroni
       PGROOT: /home/postgres/pgdata/pgroot
+      SPILO_CONFIGURATION: |
+        bootstrap:
+          post_init: /scripts/post_init_wrapper.sh "zalandos"
       # CLONE_* vars intentionally omitted here — enabled only at cutover
       # (Phase 3) to seed from the existing 41GB single instance via
       # pg_basebackup. See ADR-0001 note before cutover.
@@ -130,17 +184,28 @@ services:
       - /bin/sh
       - -c
       - |
-        export PGPASSWORD_SUPERUSER="$(cat /run/secrets/postgresql_password)"
+        export PGPASSWORD_SUPERUSER="$$(cat /run/secrets/postgresql_password)"
-        export PGPASSWORD_STANDBY="$(cat /run/secrets/postgresql_replication_password)"
+        export PGPASSWORD_STANDBY="$$(cat /run/secrets/postgresql_replication_password)"
-        export PATRONI_RESTAPI_PASSWORD="$(cat /run/secrets/postgresql_patroni_password)"
+        export PATRONI_RESTAPI_PASSWORD="$$(cat /run/secrets/postgresql_patroni_password)"
+        mkdir -p /scripts
+        cat > /scripts/post_init_wrapper.sh <<'WRAP'
+        #!/bin/bash
+        set -e
+        psql -d "$$2" -v ON_ERROR_STOP=1 -c 'DO $$do$$ BEGIN IF NOT EXISTS (SELECT 1 FROM pg_catalog.pg_roles WHERE rolname = $$x$$postgres$$x$$) THEN CREATE ROLE postgres WITH SUPERUSER NOLOGIN; END IF; END $$do$$;'
+        exec /scripts/post_init.sh "$$@"
+        WRAP
+        chmod +x /scripts/post_init_wrapper.sh
         exec /bin/sh /launch.sh init
     environment:
       SCOPE: postgres-ha
       PATRONI_NAME: patroni-1
-      ETCD_HOSTS: '"etcd-1:2379","etcd-2:2379","etcd-3:2379"'
+      ETCD3_HOSTS: '"etcd-1:2379","etcd-2:2379","etcd-3:2379"'
       PGUSER_STANDBY: standby
       PATRONI_RESTAPI_USERNAME: patroni
       PGROOT: /home/postgres/pgdata/pgroot
+      SPILO_CONFIGURATION: |
+        bootstrap:
+          post_init: /scripts/post_init_wrapper.sh "zalandos"
     secrets:
       - postgresql_password
       - postgresql_replication_password