[ERROR] failed to copy buffer

[Marek_Pastier]

hello community

I already installed the last version caddy v1.0.0 to Centos 7.6. Sometimes I have this error message.

[ERROR] failed to copy buffer: unexpected EOF

What can I do ? I tried restart the services but the problem is repeated.

[Whitestrake (Matthew Fay)]

Hi @Marek_Pastier, welcome to the Caddy community.

This could be a non-issue - but it’s impossible to tell without context. We might be able to infer more if you can provide your full Caddyfile.

[Marek_Pastier]

My caddy.services

[Unit]
Description=Caddy HTTP/2 web server
;Documentation=Welcome — Caddy Documentation
After=rpc-statd.service
Wants=rpc-statd.service

[Service]
Restart=on-failure
StartLimitInterval=86400
StartLimitBurst=5

; User and group the process will run as.
User=caddy
Group=caddy

; Use graceful shutdown with a reasonable timeout
KillMode=mixed
KillSignal=SIGQUIT
TimeoutStopSec=5s

; Letsencrypt-issued certificates will be written to this directory.
Environment=CADDYPATH=/etc/ssl/caddy

; Always set “-root” to something safe in case it gets forgotten in the Caddyfile.
ExecStart=/usr/bin/caddy -log stdout -agree=true -log=/var/log/caddy/caddy.log -conf=/etc/caddy/caddy.conf -root=/var/tmp
;ExecStart=/usr/bin/caddy -log stdout -agree=true -conf=/etc/caddy/Caddyfile -root=/var/tmp
ExecReload=/bin/kill -USR1 $MAINPID

; Limit the number of file descriptors; see man systemd.exec for more limit settings.
LimitNOFILE=1048576
; Unmodified caddy is not expected to use more than that.
LimitNPROC=64

; Use private /tmp and /var/tmp, which are discarded after caddy stops.
PrivateTmp=true
; Use a minimal /dev
PrivateDevices=true
; Hide /home, /root, and /run/user. Nobody will steal your SSH-keys.
ProtectHome=true
; Make /usr, /boot, /etc and possibly some more folders read-only.
ProtectSystem=full
; … except /etc/ssl/caddy, because we want Letsencrypt-certificates there.
; This merely retains r/w access rights, it does not add any new. Must still be writable on the host!
ReadWriteDirectories=/etc/ssl/caddy

; The following additional security directives only work with systemd v229 or later.
; They further retrict privileges that can be gained by caddy. Uncomment if you like.
; Note that you may have to add capabilities required by any plugins in use.
CapabilityBoundingSet=CAP_NET_BIND_SERVICE
AmbientCapabilities=CAP_NET_BIND_SERVICE
NoNewPrivileges=true

SyslogIdentifier=caddy
StandardOutput=syslog

[Install]
WantedBy=multi-user.target

My /etc/caddy/caddy.conf

:80 {
tls off
timeouts 5m

    #---------------------------------------------
    #[LIST OF PORTS]
    #---------------------------------------------
    #
    #
    #"ReserveListOfPorts":"50001->50099",
    #"LOCALHOST":  "50001",
    #"MAO-MD-CHI": "50002",
    #"MAO-TN-JEN": "50003",
    #"MAO-BG-KAR": "50004",
    #"MAO-BG-MEZ": "50005",
    #"MAO-MA-TAN": "50006",
    #"MAO-RO-TGJ": "50007",
    #"MAO-RO-CAR": "50008",
    #"MAO-SK-NIT": "50009",
    #"MAO-UA-TER": "50010",
    #"MAO-UA-CHE": "50011",
    #"MAO-UA-KHM": "50012",
    #"MAO-UA-CHO": "50013"
    #
    #---------------------------------------------
    #[API CONTROLLER]
    #---------------------------------------------
    proxy /CHE localhost:50011 {
            without /CHE
    }
    proxy /CHE-TEST localhost:60011 {
            without /CHE-TEST
    }
    proxy /KHM localhost:50012 {
            without /KHM
    }
    proxy /CHO localhost:50013 {
            without /CHO
    }
    proxy /CHO-TEST localhost:60013 {
            without /CHO-TEST
    }
    #---------------------------------------------
    #[API SWAGGER]
    #---------------------------------------------
    redir /swaggerCHE http://{host}:50011/swagger
    redir /swaggerCHE-TEST http://{host}:60011/swagger
    redir /swaggerKHM http://{host}:50012/swagger
    redir /swaggerCHO http://{host}:50013/swagger
    redir /swaggerCHO-TEST http://{host}:60013/swagger
    #---------------------------------------------
    #[API KPI]
    #---------------------------------------------
    #//Measurement API
    proxy /PERFORMANCE localhost:2090 {
            without /PERFORMANCE
    }
    ##proxy /performance 10.130.30.187:2090 {
    ##      without /performance
    ##}
    #---------------------------------------------
    #[CADDY LOG DEBUG]
    #---------------------------------------------
    log /var/log/caddy/default.log {
            rotate_size 50  # Rotate after 50 MB
            rotate_age  3   # Keep rotated files for 3 days
            rotate_keep 20  # Keep at most 20 log files
            rotate_compress # Compress rotated log files in gzip format
    }

}

:80/releases/ {
root /data/apps/mao-softvare-release/
browse
}

#:80/acpw/ {

root /data/apps/acpw/

browse

#}

:80/maolog/ {
root /var/ftp/mao/
browse
}

[Whitestrake (Matthew Fay)]

The error in particular is generated by Caddy’s reverse proxy code.

I would start looking at upstreams to figure out which of them might be closing a connection early (unexpected EOF generally occurs when another server stops sending data mid-stream).

[Marek_Pastier]

@Whitestrake

I would start looking at upstreams to figure out which of them might be closing a connection early (unexpected EOF generally occurs when another server stops sending data mid-stream).

How Can I check upstream ,please ?

[Whitestrake (Matthew Fay)]

Depends on what software you’re running upstream.

It might have its own logging procedures or troubleshooting methods.

[uchagani (UC)]

I’m getting this same issue every time I refresh the site. Home Assistant in this case. Here is my config:

my.domain.com {
  proxy / 192.168.1.180:8123 {
    websocket
    transparent
  }

  tls my@email.com {
    dns cloudflare
  }
}

[Whitestrake (Matthew Fay)]

Does it happen with any other reverse proxy? Have you done any troubleshooting on Home Assistant?