Initial clean commit

init-replica/init-replica.sh

@@ -0,0 +1,53 @@
+#!/bin/bash
+# Initialization script for PostgreSQL streaming replica
+# This script sets up the replica from the primary using pg_basebackup
+
+set -e
+
+PGDATA="${PGDATA:-/var/lib/postgresql/data/18/main}"
+PRIMARY_HOST="${PRIMARY_HOST:-db}"
+REPLICATION_USER="${REPLICATION_USER:-replicator}"
+REPLICATION_PASSWORD="${REPLICATION_PASSWORD:-replica_password}"
+
+echo "=== PostgreSQL Replica Initialization ==="
+
+# Check if PGDATA already has data (replica already initialized)
+if [ -f "$PGDATA/standby.signal" ]; then
+    echo "Replica already initialized (standby.signal exists). Skipping initialization."
+    exit 0
+fi
+
+if [ -f "$PGDATA/PG_VERSION" ]; then
+    echo "PGDATA already contains data. Checking if it's a replica..."
+    if [ -f "$PGDATA/standby.signal" ] || grep -q "primary_conninfo" "$PGDATA/postgresql.auto.conf" 2>/dev/null; then
+        echo "Already configured as replica. Skipping."
+        exit 0
+    else
+        echo "WARNING: PGDATA contains data but is NOT a replica."
+        echo "Cleaning up existing data to initialize replica..."
+        rm -rf "$PGDATA"/*
+        # Continue to basebackup
+    fi
+fi
+
+echo "Waiting for primary at $PRIMARY_HOST to be ready..."
+until pg_isready -h "$PRIMARY_HOST" -p 5432 -U postgres; do
+    echo "Primary not ready yet. Waiting 2 seconds..."
+    sleep 2
+done
+
+echo "Primary is ready. Starting pg_basebackup..."
+
+# Use pg_basebackup to copy data from primary
+PGPASSWORD="$REPLICATION_PASSWORD" pg_basebackup \
+    -h "$PRIMARY_HOST" \
+    -p 5432 \
+    -U "$REPLICATION_USER" \
+    -D "$PGDATA" \
+    -Fp \
+    -Xs \
+    -P \
+    -R
+
+echo "pg_basebackup complete. Replica initialized successfully."
+echo "standby.signal and postgresql.auto.conf with primary_conninfo created."