minio/buildscripts/healthcheck.sh

#!/bin/sh
#
# Minio Cloud Storage, (C) 2017 Minio, Inc.
#
# 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.
#

_init () {
    scheme="http://"
    address="127.0.0.1:9000"
    resource="/minio/index.html"
    start=$(stat -c "%Y" /proc/1)
}

healthcheck_main () {
    # In distributed environment like Swarm, traffic is routed 
    # to a container only when it reports a `healthy` status. So, we exit 
    # with 0 to ensure healthy status till distributed Minio starts (120s). 
    #
    # Refer: https://github.com/moby/moby/pull/28938#issuecomment-301753272
    if [ $(( $(date +%s) - start )) -lt 120 ]; then
        exit 0
    else
        # Get the http response code
        http_response=$(curl -s -k -o /dev/null -I -w "%{http_code}" \
            ${scheme}${address}${resource})

        # Get the http response body
        http_response_body=$(curl -k -s ${scheme}${address}${resource})

        # server returns response 403 and body "SSL required" if non-TLS 
        # connection is attempted on a TLS-configured server. Change
        # the scheme and try again
        if [ "$http_response" = "403" ] && \
        [ "$http_response_body" = "SSL required" ]; then
            scheme="https://"
            http_response=$(curl -s -k -o /dev/null -I -w "%{http_code}" \
                ${scheme}${address}${resource})
        fi

        # If http_repsonse is 200 - server is up. When MINIO_BROWSER is 
        # set to off, curl responds with 404. We assume that the server
        # is up
        [ "$http_response" = "200" ] || [ "$http_response" = "404" ]
    fi
}

_init && healthcheck_main