How do I get lighttpd access log to stdout?

Question

I am running lighttpd in a docker container on Ubuntu (as a service that must always be up in my traefik setup). My docker-compose.yml contains:

  lighttpd:
    image: sebp/lighttpd
    container_name: lighttpd
    restart: unless-stopped
    volumes:
      - /srv/docker/traefik/lighttpd/etc/lighttpd.conf:/etc/lighttpd/lighttpd.conf
      - /srv/docker/traefik/lighttpd/log/error.log:/var/log/lighttpd/error.log
      - /srv/docker/traefik/lighttpd/log/access.log:/var/log/lighttpd/access.log
      - /var/www/miniserver/html/:/var/www/html/
    ports:
      - "80"
    tty: true
    labels:
      - "traefik.enable=true"
      - "traefik.http.routers.lighttpd.rule=Host(`foo.rna.nl`)"
      - "traefik.http.routers.lighttpd.entrypoints=web"
      - "traefik.http.routers.lighttpd.tls=false"
    networks:
      - proxy

lighttpd works, serves me index.html, but:

# docker logs lighttpd
2022-10-29 12:13:55: (server.c.1568) server started (lighttpd/1.4.64)

I get the startup message, but nothing else. When I direct access log to a file, I get access log entries there:

172.26.0.2 foo.rna.nl - [29/Oct/2022:11:53:02 +0000] "GET /index.html HTTP/1.1" 200 37 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.0 Safari/605.1.15"

How do I direct lighttpd's access log to stdout? I tried both of these:

accesslog.filename = "/proc/self/fd/1"
accesslog.filename = "/dev/stdout"

My full lighttpd.conf:

server.modules = (
    "mod_indexfile",
    "mod_access",
    "mod_alias",
    "mod_redirect",
    "mod_accesslog",
)

server.document-root = "/var/www/html" 
#server.errorlog = "/var/log/lighttpd/error.log"
server.port = 80

mimetype.assign = (
  ".html" => "text/html", 
  ".txt" => "text/plain",
  ".jpg" => "image/jpeg",
  ".png" => "image/png" 
)

accesslog.filename = "/proc/self/fd/1"
#accesslog.filename = "/dev/stdout"
#accesslog.filename = "/var/log/lighttpd/access.log"

score 1 · Accepted Answer · answered Oct 29 '22 at 13:42

It looks like Lighttpd must close stdout when it start up, so you can't send output there, but you can send access logs to stderr:

accesslog.filename = "/dev/fd/2"

(Or /proc/self/fd/2 if you prefer.)

If you really want logs on stdout instead of stderr, you can perform some fd redirection tricks as shown here:

Redirect a new fd to the original stdout:

#!/bin/sh
exec 3>&1
lighttpd -D -f /etc/lighttpd/lighttpd.conf

Point the access log at the new fd:
```
accesslog.filename = "/dev/fd/3" 
```

This requires overriding the existing container startup command with a shell script.

I tried using fd2 for `accesslog.filename` and that works, thanks. Redirection means I must change the default startup of the `lighttpd` container, maybe try that later because I don't know how to easily do that using `docker compose`. — gctwnl, Oct 31 '22 at 13:21

How do I get lighttpd access log to stdout?

1 Answers1