docker-run.sh

#!/usr/bin/env bash
declare -a array
declare -i length current
set -e

NGINX_ROOT=/usr/share/nginx/html
SPEC_ROOT=$NGINX_ROOT/specs
INDEX_FILE=$NGINX_ROOT/index.html
API_URLS="["

array=($SPEC_ROOT/*.yaml)
length=${#array[@]}
current=0

for filename in $SPEC_ROOT/*.yaml; do
    current=$((current + 1))
    name=${filename##*/}
    base=${name%.yaml}

    if [[ "$current" -eq "$length" ]]; then
        API_URLS+="{url: \"./specs/$name\", name: \"$base\"}]"
    else
        API_URLS+="{url: \"./specs/$name\", name: \"$base\"}, "
    fi
done

## replace `url` with `urls` option if API_URLS is set
if [[ -n "$API_URLS" ]]; then
    sed -i "s|^\(\s*\)url: .*,|\1urls: $API_URLS,|g" $INDEX_FILE
fi

exec nginx -g 'daemon off;'

Dockerfile

FROM swaggerapi/swagger-ui

RUN apk add bash && \
    mkdir -p /usr/share/nginx/html/specs && \
    chown -R nginx:nginx /usr/share/nginx/html/specs

COPY ./api_docs/* /usr/share/nginx/html/specs/
COPY ./docker-run.sh /usr/share/nginx/

RUN chmod +x /usr/share/nginx/docker-run.sh

CMD ["/bin/bash", "/usr/share/nginx/docker-run.sh"]