Add backup and restore script for Vitess tablets

Signed-off-by: Shail Pujan <[email protected]>

examples/local/401_backup_restore.sh

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+#!/bin/bash
+
+# Copyright 2019 The Vitess Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# This script demonstrates how to create backups and restore tablets in Vitess.
+
+# Load common environment variables and functions from the specified file
+source ../common/env.sh
+
+# Set the keyspace and shard variables
+KEYSPACE="commerce"  # Define the keyspace we will work with, which is 'commerce'
+SHARD="0"            # Define the shard we will operate on, which is shard '0'
+
+# Helper function for logging messages with timestamps
+log() {
+    # Print the current date, time, and log message to standard output
+    echo "$(date +'%Y-%m-%d %H:%M:%S') - $1"
+}
+
+# Ensure the keyspace exists and is healthy
+log "Ensuring keyspace $KEYSPACE exists and shard $SHARD is healthy..."
+# Wait for the specified shard to be healthy. If it is not healthy, exit the script with an error.
+wait_for_healthy_shard $KEYSPACE $SHARD || exit 1
+
+# Find the replica tablets dynamically
+log "Finding replica tablets..."
+# Use vtctldclient to get a list of replica tablets in the specified keyspace and shard,
+# extracting just the tablet names using awk.
+REPLICA_TABLETS=$(vtctldclient GetTablets --keyspace=$KEYSPACE --shard=$SHARD --tablet-type=replica | awk '{print $1}')
+# Count the number of replica tablets found
+REPLICA_COUNT=$(echo "$REPLICA_TABLETS" | wc -l)
+
+# Check if any replica tablets were found
+if [ "$REPLICA_COUNT" -lt 1 ]; then
+    log "No replica tablets found. Attempting to temporarily demote primary for restore..."
+
+    # If no replica tablets exist, find the primary tablet
+    PRIMARY_TABLET=$(vtctldclient GetTablets --keyspace=$KEYSPACE --shard=$SHARD --tablet-type=primary | awk '{print $1}')
+    log "Demoting primary tablet ($PRIMARY_TABLET) to replica mode for restore..."
+
+    # Temporarily demote the primary tablet to a replica so it can be restored
+    vtctldclient ChangeTabletType $PRIMARY_TABLET replica || fail "Failed to demote primary to replica"
+
+    # Set the restore tablet to the primary tablet (now demoted)
+    RESTORE_TABLET=$PRIMARY_TABLET
+else
+    # If there are replicas, select the first replica tablet for the restore process
+    RESTORE_TABLET=$(echo "$REPLICA_TABLETS" | head -n 1)
+fi
+
+# Restore from the backup on the chosen tablet
+log "Restoring tablet $RESTORE_TABLET from backup..."
+# Call the RestoreFromBackup command on the selected tablet. If it fails, exit with an error.
+vtctldclient RestoreFromBackup $RESTORE_TABLET || fail "Restore failed for tablet $RESTORE_TABLET"
+
+# Check if the primary tablet was the one that was restored
+if [ "$PRIMARY_TABLET" = "$RESTORE_TABLET" ]; then
+    log "Promoting tablet $PRIMARY_TABLET back to primary..."
+    # If the restored tablet was the primary, promote it back to primary status
+    vtctldclient ChangeTabletType $PRIMARY_TABLET primary || fail "Failed to promote replica back to primary"
+fi
+
+# Complete the process with a success message
+log "Backup and Restore example completed successfully."

examples/local/501_teardown.sh

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+#!/bin/bash
+
+# Copyright 2019 The Vitess Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# We should not assume that any of the steps have been executed.
+# This makes it possible for a user to cleanup at any point.
+
+source ../common/env.sh
+
+../common/scripts/vtadmin-down.sh
+
+../common/scripts/vtorc-down.sh
+
+../common/scripts/vtgate-down.sh
+
+for tablet in 100 200 300 400 500; do
+	if vtctldclient --action_timeout 1s --server localhost:15999 GetTablet zone1-$tablet >/dev/null 2>&1; then
+		# The zero tablet is up. Try to shutdown 0-2 tablet + mysqlctl
+		for i in 0 1 2; do
+			uid=$((tablet + i))
+			printf -v alias '%s-%010d' 'zone1' $uid
+			echo "Shutting down tablet $alias"
+			CELL=zone1 TABLET_UID=$uid ../common/scripts/vttablet-down.sh
+   			# because MySQL takes time to stop, we do this in parallel
+			CELL=zone1 TABLET_UID=$uid ../common/scripts/mysqlctl-down.sh &
+		done
+
+  		# without a sleep below, we can have the echo happen before the echo of mysqlctl-down.sh
+                sleep 2
+                echo "Waiting mysqlctl to stop..."
+                wait
+                echo "mysqlctls are stopped!"
+	fi
+done
+
+../common/scripts/vtctld-down.sh
+
+if [ "${TOPO}" = "zk2" ]; then
+	CELL=zone1 ../common/scripts/zk-down.sh
+elif [ "${TOPO}" = "consul" ]; then
+	CELL=zone1 ../common/scripts/consul-down.sh
+else
+	CELL=zone1 ../common/scripts/etcd-down.sh
+fi
+
+# pedantic check: grep for any remaining processes
+
+if [ -n "$VTDATAROOT" ]; then
+	if pgrep -f -l "$VTDATAROOT" >/dev/null; then
+		echo "ERROR: Stale processes detected! It is recommended to manuallly kill them:"
+		pgrep -f -l "$VTDATAROOT"
+	else
+		echo "All good! It looks like every process has shut down"
+	fi
+
+	# shellcheck disable=SC2086
+	rm -r ${VTDATAROOT:?}/*
+fi
+
+disown -a