Docker Run without “docker run”

So there was this one question on Stackoverflow in which the OP was linking an .htaccess tester for Mod-Rewrite-Rules. Despite this being all fine I was asking myself what about really(tm) testing this?

So I remembered the rewrite-log from the days ago and thought: Why not just fire up a docker container, do the setup for testing rewrites by turning the logs to screaming and give it a drive.

But all the setup.

So I had an idea: What about you put the whole example into the Dockerfile? It has the RUN directive, so the moment the image builds it is actually executing it.

Having it exit non-zero even prevents of storing the image locally.

Ah yeah, and why actually write a Dockerfile even.

	<<'EOD' docker build –rm –tag rewrite-tester –no-cache –
	FROM httpd:alpine
	RUN set -e \
	; sed -i -e 's/^#LoadModule rewrite_module/LoadModule rewrite_module/' \
	-e 's/^LogLevel .*$/LogLevel debug rewrite:trace8/' \
	-e '\|<Directory "/usr/local/apache2/htdocs">|,\ </Directory> s/^ AllowOverride .*$/ AllowOverride All/' \
	/usr/local/apache2/conf/httpd.conf \
	; echo -e ' \n\
	RewriteEngine On \n\
	RewriteBase / \n\
	RewriteCond %{REQUEST_URI} \.(gif|jpg|jpeg|png)$ \n\
	RewriteRule ^(.*)$ $1?i=jplx [DPI,QSA] \n\
	RewriteCond %{REQUEST_URI} !^/sites/default/files/js/ \n\
	RewriteCond %{REQUEST_URI} !^/sites/default/files/css/ \n\
	RewriteRule ^sites/default/files/(.*)$ index.php?q=system/files/$1 [END,QSA,R] \n\
	' | tee /usr/local/apache2/htdocs/.htaccess \
	; httpd-foreground & sleep 1 \
	; apk add curl \
	; curl -I 'http://127.0.0.1/sites/default/files/Slide074.png?abc&#39; \
	; exit 123
	EOD
	;: https://stackoverflow.com/a/58527089/367456

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docker-minimal-example.sh

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Explainshell

This also clearly highlights a missing feature in docker: no support for here-doc strings in the Dockerfile since 2013, echo -e to the rescue (but it’s cumbersome).