consul_sync_check.sh

#!/bin/bash

# Wait until consul instance on clust
INSTANCE_IP="127.0.0.1"
NEXT_WAIT_TIME=0
MAX_WAIT_TIME=35


check_consul_sync() {
    # If we don't have leaders _last_log_index then get it
    if [[ -z "${leader_last_log_index}" ]]; then
        # Get leader
        echo $(curl -s localhost:8500/v1/agent/self | jq -r '.Stats.consul')
        leader_addr=$(curl -s localhost:8500/v1/agent/self | jq -r '.Stats.consul.leader_addr | split(":")[0] | select(. != null)')

        if [[ -z "${leader_addr}" ]]; then
            echo 'Not known leader'
            return 1 # true
        fi
        echo "Leader addr: ${leader_addr}"

        # Get last log index from leader
        leader_last_log_index=$(curl -s ${leader_addr}:8500/v1/agent/self | jq -r '.Stats.raft.last_log_index')
        echo "Leader agent last_log_index: ${leader_last_log_index}"
    fi

    # Get last log index from local agent
    local_last_log_index=$(curl -s localhost:8500/v1/agent/self | jq -r '.Stats.raft.last_log_index')
    echo "Local agent last_log_index: ${local_last_log_index}"

    # Check local node greater or equal to leader
    if [[ "${local_last_log_index}" -ge "${leader_last_log_index}" ]]; then
        echo 'Synced!'
        return 0 # true
    fi

    echo 'Not synced yet'
    return 1 # False
}

until  [[ "${NEXT_WAIT_TIME}" -eq "${MAX_WAIT_TIME}" ]] || check_consul_sync ; do
    (( NEXT_WAIT_TIME++ ))
    echo "Waiting ${NEXT_WAIT_TIME} seconds until next check... (${NEXT_WAIT_TIME}/${MAX_WAIT_TIME})"
    sleep ${NEXT_WAIT_TIME}
done

# If we used our max retry the exit
if [[ "${NEXT_WAIT_TIME}" -eq "${MAX_WAIT_TIME}" ]]; then
    echo 'Consul Server not ready'
    false
else
    echo 'Consul peer ready! :)'
fi