OpenGrok:

opengrok version: opengrok-0.12.1.5

image base on: tomcat:8.0

to start:

sudo docker run --rm \
    -v /path/to/source:/src \
    -v /path/to/opengrok_data:/data \
    -p 8888:8080 \
    scue/docker-opengrok

then, the search engine is available at http://localhost:8888/.