docker sample file one added

Author: codershona

docker-2.md

@@ -124,6 +124,8 @@ docker image push codersh/nginx:testing
 docker image ls
 ```
 ## Building Images Using The Dockerfile Basics :
+
+
 ```
 cd dockerfile-sample-1
 

dockerfile-sample-1/Dockerfile

@@ -0,0 +1,54 @@
+# NOTE: this example is taken from the default Dockerfile for the official nginx Docker Hub Repo
+# https://hub.docker.com/_/nginx/
+# NOTE: This file is slightly different than the video, because nginx versions have been updated 
+#       to match the latest standards from docker hub... but it's doing the same thing as the video
+#       describes
+FROM debian:stretch-slim
+# all images must have a FROM
+# usually from a minimal Linux distribution like debian or (even better) alpine
+# if you truly want to start with an empty container, use FROM scratch
+
+ENV NGINX_VERSION 1.13.6-1~stretch
+ENV NJS_VERSION   1.13.6.0.1.14-1~stretch
+# optional environment variable that's used in later lines and set as envvar when container is running
+
+RUN apt-get update \
+	&& apt-get install --no-install-recommends --no-install-suggests -y gnupg1 \
+	&& \
+	NGINX_GPGKEY=573BFD6B3D8FBC641079A6ABABF5BD827BD9BF62; \
+	found=''; \
+	for server in \
+		ha.pool.sks-keyservers.net \
+		hkp://keyserver.ubuntu.com:80 \
+		hkp://p80.pool.sks-keyservers.net:80 \
+		pgp.mit.edu \
+	; do \
+		echo "Fetching GPG key $NGINX_GPGKEY from $server"; \
+		apt-key adv --keyserver "$server" --keyserver-options timeout=10 --recv-keys "$NGINX_GPGKEY" && found=yes && break; \
+	done; \
+	test -z "$found" && echo >&2 "error: failed to fetch GPG key $NGINX_GPGKEY" && exit 1; \
+	apt-get remove --purge -y gnupg1 && apt-get -y --purge autoremove && rm -rf /var/lib/apt/lists/* \
+	&& echo "deb http://nginx.org/packages/mainline/debian/ stretch nginx" >> /etc/apt/sources.list \
+	&& apt-get update \
+	&& apt-get install --no-install-recommends --no-install-suggests -y \
+						nginx=${NGINX_VERSION} \
+						nginx-module-xslt=${NGINX_VERSION} \
+						nginx-module-geoip=${NGINX_VERSION} \
+						nginx-module-image-filter=${NGINX_VERSION} \
+						nginx-module-njs=${NJS_VERSION} \
+						gettext-base \
+	&& rm -rf /var/lib/apt/lists/*
+# optional commands to run at shell inside container at build time
+# this one adds package repo for nginx from nginx.org and installs it
+
+RUN ln -sf /dev/stdout /var/log/nginx/access.log \
+	&& ln -sf /dev/stderr /var/log/nginx/error.log
+# forward request and error logs to docker log collector
+
+EXPOSE 80 443
+# expose these ports on the docker virtual network
+# you still need to use -p or -P to open/forward these ports on host
+
+CMD ["nginx", "-g", "daemon off;"]
+# required: run this command when container is launched
+# only one CMD allowed, so if there are multiple, last one wins