[sonic-slave]: Split user commands from generic. (#868)

In case when more than one user builds SONiC on same machine, we can
keep generic part that installs all packages to slave image apart from
creating user and calling user-related commands. Then generic base image
will be built only once, allowing other users to build only smaller
specific to them layers.

Signed-off-by: marian-pritsak <marianp@mellanox.com>

Makefile

@@ -12,7 +12,9 @@ $(shell rm -f .screen)
 
 MAKEFLAGS += -B
 
-SLAVE_TAG = $(shell shasum sonic-slave/Dockerfile | awk '{print substr($$1,0,11);}')
+SLAVE_BASE_TAG = $(shell shasum sonic-slave/Dockerfile | awk '{print substr($$1,0,11);}')
+SLAVE_TAG = $(shell shasum sonic-slave/Dockerfile.user | awk '{print substr($$1,0,11);}')
+SLAVE_BASE_IMAGE = sonic-slave-base
 SLAVE_IMAGE = sonic-slave-$(USER)
 
 DOCKER_RUN := docker run --rm=true --privileged \
@@ -20,12 +22,18 @@ DOCKER_RUN := docker run --rm=true --privileged \
     -w /sonic \
     -i$(if $(TERM),t,)
 
+DOCKER_BASE_BUILD = docker build --no-cache \
+		    -t $(SLAVE_BASE_IMAGE) \
+		    sonic-slave && \
+		    docker tag $(SLAVE_BASE_IMAGE):latest $(SLAVE_BASE_IMAGE):$(SLAVE_BASE_TAG)
+
 DOCKER_BUILD = docker build --no-cache \
 	       --build-arg user=$(USER) \
 	       --build-arg uid=$(shell id -u) \
 	       --build-arg guid=$(shell id -g) \
 	       --build-arg hostname=$(shell echo $$HOSTNAME) \
 	       -t $(SLAVE_IMAGE) \
+	       -f sonic-slave/Dockerfile.user \
 	       sonic-slave && \
 	       docker tag $(SLAVE_IMAGE):latest $(SLAVE_IMAGE):$(SLAVE_TAG)
 
@@ -34,6 +42,9 @@ DOCKER_BUILD = docker build --no-cache \
 .DEFAULT_GOAL :=  all
 
 %::
+	@docker inspect --type image $(SLAVE_BASE_IMAGE):$(SLAVE_BASE_TAG) &> /dev/null || \
+	    { echo Image $(SLAVE_BASE_IMAGE):$(SLAVE_BASE_TAG) not found. Building... ; \
+	    $(DOCKER_BASE_BUILD) ; }
 	@docker inspect --type image $(SLAVE_IMAGE):$(SLAVE_TAG) &> /dev/null || \
 	    { echo Image $(SLAVE_IMAGE):$(SLAVE_TAG) not found. Building... ; \
 	    $(DOCKER_BUILD) ; }
@@ -49,9 +60,13 @@ DOCKER_BUILD = docker build --no-cache \
 	    $@
 
 sonic-slave-build :
-	@$(DOCKER_BUILD)
+	$(DOCKER_BASE_BUILD)
+	$(DOCKER_BUILD)
 
 sonic-slave-bash :
+	@docker inspect --type image $(SLAVE_BASE_IMAGE):$(SLAVE_BASE_TAG) &> /dev/null || \
+	    { echo Image $(SLAVE_BASE_IMAGE):$(SLAVE_BASE_TAG) not found. Building... ; \
+	    $(DOCKER_BASE_BUILD) ; }
 	@docker inspect --type image $(SLAVE_IMAGE):$(SLAVE_TAG) &> /dev/null || \
 	    { echo Image $(SLAVE_IMAGE):$(SLAVE_TAG) not found. Building... ; \
 	    $(DOCKER_BUILD) ; }

sonic-slave/Dockerfile

@@ -254,31 +254,3 @@ RUN add-apt-repository \
 RUN apt-get update
 RUN apt-get install -y docker-ce=17.03.2~ce-0~debian-jessie
 RUN echo "DOCKER_OPTS=\"--experimental\"" >> /etc/default/docker
-
-# Add user
-ARG user
-ARG uid
-ARG guid
-ARG hostname
-
-ENV BUILD_HOSTNAME $hostname
-ENV USER $user
-
-RUN groupadd -f -r -g $guid g$user
-
-RUN useradd $user -l -u $uid -g $guid -d /var/$user -m -s /bin/bash
-
-RUN gpasswd -a $user docker
-
-# Config git for stg
-RUN su $user -c "git config --global user.name $user"
-RUN su $user -c "git config --global user.email $user@contoso.com"
-
-COPY sonic-jenkins-id_rsa.pub /var/$user/.ssh/authorized_keys2
-RUN chown $user /var/$user/.ssh -R
-RUN chmod go= /var/$user/.ssh -R
-
-# Add user to sudoers
-RUN echo "$user ALL=(ALL) NOPASSWD:ALL" >>/etc/sudoers
-
-USER $user

sonic-slave/Dockerfile.user

@@ -0,0 +1,29 @@
+FROM sonic-slave-base
+
+# Add user
+ARG user
+ARG uid
+ARG guid
+ARG hostname
+
+ENV BUILD_HOSTNAME $hostname
+ENV USER $user
+
+RUN groupadd -f -r -g $guid g$user
+
+RUN useradd $user -l -u $uid -g $guid -d /var/$user -m -s /bin/bash
+
+RUN gpasswd -a $user docker
+
+# Config git for stg
+RUN su $user -c "git config --global user.name $user"
+RUN su $user -c "git config --global user.email $user@contoso.com"
+
+COPY sonic-jenkins-id_rsa.pub /var/$user/.ssh/authorized_keys2
+RUN chown $user /var/$user/.ssh -R
+RUN chmod go= /var/$user/.ssh -R
+
+# Add user to sudoers
+RUN echo "$user ALL=(ALL) NOPASSWD:ALL" >>/etc/sudoers
+
+USER $user