Repository: containrrr/watchtower

Issue #244: Synology error: Invalid Character 'p'
Created: 2018-11-24T22:55:23Z
In the last 10 days or so, without any Docker mods from me, I've started to get constant errors emailed through and I don't know where to start. Could be a Synology update that has killed things?
watchtower
date,stream,content
2018-11-24 11:10:23,stderr,time="2018-11-24T11:10:23Z" level=info msg="Waiting for running update to be finished..." 

2018-11-24 10:46:49,stderr,"time=\"2018-11-24T10:46:49Z\" level=info msg=\"Unable to update container /watchtower, err='Error response from daemon: unauthorized: authentication required'. Proceeding to next.\" 
"
2018-11-24 10:21:44,stderr,"time=\"2018-11-24T10:21:44Z\" level=info msg=\"Unable to update container /unifi, err='Error response from daemon: error parsing HTTP 404 response body: invalid character 'p' after top-level value: \"404 page not found\n\"'. Proceeding to next.\" 
"
2018-11-24 10:06:45,stderr,"time=\"2018-11-24T10:06:45Z\" level=info msg=\"Unable to update container /tasmoadmin, err='Error response from daemon: unauthorized: authentication required'. Proceeding to next.\" 
"
2018-11-24 09:11:50,stderr,"time=\"2018-11-24T09:11:50Z\" level=info msg=\"Unable to update container /watchtower, err='Error response from daemon: error parsing HTTP 404 response body: invalid character 'p' after top-level value: \"404 page not found\n\"'. Proceeding to next.\" 
"
2018-11-24 09:11:41,stderr,"time=\"2018-11-24T09:11:41Z\" level=info msg=\"Unable to update container /mqtt, err='Error response from daemon: error parsing HTTP 404 response body: invalid character 'p' after top-level value: \"404 page not found\n\"'. Proceeding to next.\" 

2018-11-24 08:21:43,stderr,"time=\"2018-11-24T08:21:43Z\" level=info msg=\"Unable to update container /unifi, err='Error response from daemon: error parsing HTTP 404 response body: invalid character 'p' after top-level value: \"404 page not found\n\"'. Proceeding to next.\" 

Any clues?

Duplicate issue #192: Unable to Update Containers - i/o Timeout via DNS Lookup?
Created: 2018-05-18T23:12:57Z
I'm getting the following error on a container update:
time="2018-05-17T23:48:48-05:00" level=info msg="Unable to update container /portainer, err='Error response from daemon: Get https://registry-1.docker.io/v2/portainer/portainer/manifests/latest: Get https://auth.docker.io/token?scope=repository%3Aportainer%2Fportainer%3Apull&service=registry.docker.io: dial tcp: lookup auth.docker.io on xxx.xxx.xxx.xxx:53: read udp xxx.xxx.xxx.xxx:45264->xxx.xxx.xxx.xxx:53: i/o timeout'. Proceeding to next." 

Docker-Compose to launch Watchtower is:
# ----------------------------------------
    # WATCHTOWER
    # Automatic Update Service for Docker VMs
    # ----------------------------------------
    watchtower:
        image: v2tec/watchtower
        container_name: watchtower
        restart: unless-stopped
        environment:
            - TZ=${TZ}
            - WATCHTOWER_NOTIFICATIONS=email
            - WATCHTOWER_NOTIFICATION_EMAIL_FROM=${SMTP_FROM}
            - WATCHTOWER_NOTIFICATION_EMAIL_TO=${WATCHTOWER_EMAIL}
            - WATCHTOWER_NOTIFICATION_EMAIL_SERVER=${SMTP_SERVER}
            - WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PORT=${SMTP_PORT}
            - WATCHTOWER_NOTIFICATION_EMAIL_SERVER_USER=${SMTP_USER}
            - WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD=${SMTP_PASS}
        network_mode: 'bridge'
        volumes:
            - '/var/run/docker.sock:/var/run/docker.sock'
            - '/etc/ssl/certs:/etc/ssl/certs'
        command: portainer --schedule @midnight --cleanup

Potentially the only thing I can see here is that I run Pi-Hole in front of my DNS, but I don't see anything being blocked there...

Closing comment (2018-11-26T08:19:56Z): I'm getting new (similar) errors with all containers for the last 2 days:
2018-11-25 22:57:38 (info): Unable to update container /unifi, err='Error response from daemon: error parsing HTTP 404 response body: invalid character 'p' after top-level value: "404 page not found\n"'. Proceeding to next.

This is related to #244 or better docker/hub-feedback#1693.