chore: Add postgres dependency for server to startup (#36585)

## Description
As in the past we have seen the corruption of postgres DB which is being
used for temporal we want to make sure we have a retry mechanism in
place if:
1. `APPSMITH_DB_URL` is pointing to postgres url
2. Postgres is waiting in recovery mode

As per local testing when the docker container is abruptly shutdown via
`docker rm -f {container_name}` or `docker kill {container_name}` or
even via docker desktop we end up in state where postgres goes into
recovery state.
logs:
```
2024-09-27 08:02:49 backend stdout | SQL State  : 57P03
2024-09-27 08:02:49 backend stdout | Error Code : 0
2024-09-27 08:02:49 backend stdout | Message    : FATAL: the database system is starting up
```
Currently we have implemented polling mechanism, but we will keep
looking for better alternative here if we can opt for.

Note: 
1. With release dump this is taking ~300sec to get out of that state and
start accepting the connections.
2. With the existing implementation without retries server dies down
within 60sec.
```
INFO exited: backend (exit status 1; not expected)
INFO gave up: backend entered FATAL state, too many start retries too quickly
```
Reference doc:
https://www.notion.so/appsmith/Postgres-critical-scenarios-668f49c96aef40308e24c2a8d6b1137c

/test Sanity

### 🔍 Cypress test results
<!-- This is an auto-generated comment: Cypress test results  -->
> [!TIP]
> 🟢 🟢 🟢 All cypress tests have passed! 🎉 🎉 🎉
> Workflow run:
<https://github.com/appsmithorg/appsmith/actions/runs/11100944184>
> Commit: 9dbbe4b
> <a
href="https://internal.appsmith.com/app/cypress-dashboard/rundetails-65890b3c81d7400d08fa9ee5?branch=master&workflowId=11100944184&attempt=1"
target="_blank">Cypress dashboard</a>.
> Tags: `@tag.Sanity`
> Spec:
> <hr>Mon, 30 Sep 2024 07:26:41 UTC
<!-- end of auto-generated comment: Cypress test results  -->


## Communication
Should the DevRel and Marketing teams inform users about this change?
- [ ] Yes
- [x] No


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

## Summary by CodeRabbit

- **New Features**
- Introduced new functions for enhanced handling of PostgreSQL database
connections, including availability checks and parameter extraction.
	- Added a new utility script for managing PostgreSQL connections.
- **Bug Fixes**
- Implemented a retry mechanism for PostgreSQL server availability
checks to ensure more reliable connections.
- **Tests**
- Added unit tests to validate the functionality of the PostgreSQL
parameter extraction logic.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

deploy/docker/fs/opt/appsmith/pg-utils.sh

@@ -0,0 +1,92 @@
+#!/bin/bash
+
+waitForPostgresAvailability() {
+  if [ -z "$PG_DB_HOST" ]; then
+    tlog "PostgreSQL host name is empty. Check env variables. Error. Exiting java setup"
+    exit 2
+  else
+
+    MAX_RETRIES=50
+    RETRYSECONDS=10
+    retry_count=0
+    while true; do
+      su postgres -c "pg_isready -h '${PG_DB_HOST}' -p '${PG_DB_PORT}'"
+      status=$?
+
+      case $status in
+      0)
+        tlog "PostgreSQL host '$PG_DB_HOST' is ready."
+        break
+        ;;
+      1)
+        tlog "PostgreSQL host '$PG_DB_HOST' is rejecting connections e.g. due to being in recovery mode or not accepting connections eg. connections maxed out."
+        ;;
+      2)
+        tlog "PostgreSQL host '$PG_DB_HOST' is not responding or running."
+        ;;
+      3)
+        tlog "The connection check failed e.g. due to network issues or incorrect parameters."
+        ;;
+      *)
+        tlog "pg_isready exited with unexpected status code: $status"
+        break
+        ;;
+      esac
+
+      retry_count=$((retry_count + 1))
+      if [ $retry_count -le $MAX_RETRIES ]; then
+        tlog "PostgreSQL connection failed. Retrying attempt $retry_count/$MAX_RETRIES in $RETRYSECONDS seconds..."
+        sleep $RETRYSECONDS
+      else
+        tlog "Exceeded maximum retry attempts ($MAX_RETRIES). Exiting."
+        # use exit code 2 to indicate that the script failed to connect to postgres and supervisor conf is set not to restart the program for 2.
+        exit 2
+      fi
+
+    done
+  fi
+}
+
+# for PostgreSQL, we use APPSMITH_DB_URL=postgresql://username:password@postgresserver:5432/dbname
+# Args:
+#     conn_string (string): PostgreSQL connection string
+# Returns:
+#     None
+# Example:
+#     postgres syntax
+#       "postgresql://user:password@localhost:5432/appsmith"
+#       "postgresql://user:password@localhost/appsmith"
+#       "postgresql://user@localhost:5432/appsmith"
+#       "postgresql://user@localhost/appsmith"
+extract_postgres_db_params() {
+  local conn_string=$1
+
+  # Use node to parse the URI and extract components
+  IFS=' ' read -r USER PASSWORD HOST PORT DB <<<"$(node -e "
+    const connectionString = process.argv[1];
+    const pgUri = connectionString.startsWith(\"postgresql://\")
+      ? connectionString
+      : 'http://' + connectionString; //Prepend a fake scheme for URL parsing
+    const url = require('url');
+    const parsedUrl = new url.URL(pgUri);
+
+    // Extract the pathname and remove the leading '/'
+    const db = parsedUrl.pathname.substring(1);
+
+    // Default the port to 5432 if it's empty
+    const port = parsedUrl.port || '5432';
+
+    console.log(\`\${parsedUrl.username || '-'} \${parsedUrl.password || '-'} \${parsedUrl.hostname} \${port} \${db}\`);
+  " "$conn_string")"
+
+  # Now, set the environment variables
+  export PG_DB_USER="$USER"
+  export PG_DB_PASSWORD="$PASSWORD"
+  export PG_DB_HOST="$HOST"
+  export PG_DB_PORT="$PORT"
+  export PG_DB_NAME="$DB"
+}
+
+# Example usage of the functions
+# waitForPostgresAvailability
+# extract_postgres_db_params "postgresql://user:password@localhost:5432/dbname"

deploy/docker/fs/opt/appsmith/run-java.sh

@@ -1,5 +1,8 @@
 #!/bin/bash
 
+# Source the helper script
+source pg-utils.sh
+
 set -o errexit
 set -o pipefail
 set -o nounset
@@ -29,6 +32,12 @@ match-proxy-url() {
   [[ -n $proxy_host ]]
 }
 
+# Extract the database parameters from the APPSMITH_DB_URL and wait for the database to be available
+if [[ "$mode" == "pg" ]]; then
+  extract_postgres_db_params "$APPSMITH_DB_URL"
+  waitForPostgresAvailability
+fi
+
 if match-proxy-url "${HTTP_PROXY-}"; then
   extra_args+=(-Dhttp.proxyHost="$proxy_host" -Dhttp.proxyPort="$proxy_port")
   if [[ -n $proxy_user ]]; then

deploy/docker/tests/test-pg-utils.sh

@@ -0,0 +1,68 @@
+#!/usr/bin/env bash
+
+set -e
+
+# Include the script to be tested
+source /Users/appsmith/Work/appsmith-ce/deploy/docker/fs/opt/appsmith/pg-utils.sh
+
+assert_equals() {
+  if [ "$1" != "$2" ]; then
+    echo "Assertion failed: expected '$2', but got '$1'"
+    return 1
+  fi
+}
+
+# Test extract_postgres_db_params function
+test_extract_postgres_db_params_valid_db_string() {
+  local conn_string="postgresql://user:password@localhost:5432/dbname"
+  extract_postgres_db_params "$conn_string"
+
+  if [ "$PG_DB_USER" != "user" ] || [ "$PG_DB_PASSWORD" != "password" ] || [ "$PG_DB_HOST" != "localhost" ] || [ "$PG_DB_PORT" != "5432" ] || [ "$PG_DB_NAME" != "dbname" ]; then
+    echo "Test failed: test_extract_postgres_db_params_valid_db_string did not extract parameters correctly"
+    echo_params
+    exit 1
+  fi
+
+  echo "Test passed: test_extract_postgres_db_params_valid_db_string"
+}
+
+test_extract_postgres_db_params_empty_dbname() {
+  local conn_string="postgresql://user:password@localhost:5432"
+  extract_postgres_db_params "$conn_string"
+
+  if [ "$PG_DB_USER" != "user" ] || [ "$PG_DB_PASSWORD" != "password" ] || [ "$PG_DB_HOST" != "localhost" ] || [ "$PG_DB_PORT" != "5432" ] || [ "$PG_DB_NAME" != "" ]; then
+    echo "Test failed: test_extract_postgres_db_params_empty_dbname did not extract parameters correctly"
+    echo_params
+    exit 1
+  fi
+
+  echo "Test passed: test_extract_postgres_db_params_empty_dbname"
+}
+
+test_extract_postgres_db_params_with_spaces() {
+  local conn_string="postgresql://user:p a s s w o r d@localhost:5432/db_name"
+  extract_postgres_db_params "$conn_string"
+
+  if [ "$PG_DB_USER" != "user" ] || [ "$PG_DB_PASSWORD" != "p%20a%20s%20s%20w%20o%20r%20d" ] || [ "$PG_DB_HOST" != "localhost" ] || [ "$PG_DB_PORT" != "5432" ] || [ "$PG_DB_NAME" != "db_name" ]; then
+    echo "Test failed: test_extract_postgres_db_params_with_spaces did not extract parameters correctly"
+    echo_params
+    exit 1
+  fi
+
+  echo "Test passed: test_extract_postgres_db_params_with_spaces"
+}
+
+echo_params() {
+  echo "PG_DB_USER: $PG_DB_USER"
+  echo "PG_DB_PASSWORD: $PG_DB_PASSWORD"
+  echo "PG_DB_HOST: $PG_DB_HOST"
+  echo "PG_DB_PORT: $PG_DB_PORT"
+  echo "PG_DB_NAME: $PG_DB_NAME"
+}
+
+# Run tests
+test_extract_postgres_db_params_valid_db_string
+test_extract_postgres_db_params_empty_dbname
+test_extract_postgres_db_params_with_spaces
+
+echo "All Tests Pass!"