How do you tell Spring Boot to send the embedded Tomcat's access logs to stdout?

Question

In a standalone Spring Boot web application (executable jar), how do you tell Spring Boot that we want the embedded Tomcat instance\'s HTTP access logs to be sent to stdout?

Answer 1

Update 2019.02.11:

These inks should be useful to map which properties you should set in application.properties:

• tomcat
• undertow

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@acohen answer is slightly correct. If you provide the empty double quotes it won't work. I will extend his answer because I think it's important for people who don't want to mess with adding dependencies or modifying code:

config/application.properties

# here we say that we want to enable accesslog
server.tomcat.accesslog.enabled=true

# it is important to understand what the options means:
# 'directory/prefix + suffix + file-date-format' will be
# the file that tomcat will try to open.
# /dev/stdout is standard output, so we want tomcat
# to write to that fd. Then, we need to play with
# directory, prefix, suffix and file-date-format to match our desired path.
server.tomcat.accesslog.directory=/dev
server.tomcat.accesslog.prefix=stdout
server.tomcat.accesslog.buffered=false

# Don't use empty double quotes, see below
server.tomcat.accesslog.suffix=
server.tomcat.accesslog.file-date-format=

Notes

1. If you set file-date-format and suffix to be double quotes, you will have this error:

java.io.FileNotFoundException: /dev/stdout"""" (Permission denied)

2. If you don't include them in the config file, you will then be using defaults values and this error:

java.io.FileNotFoundException: /dev/stdout.2019-02-07.log (Permission denied)

3. If you leave them empty, then it will work.