[PATCH v5 2/3] automation: Add a clean rule for containers

[Bertrand Marquis <bertrand.marquis@xxxxxxx>]

Add make clean support to remove the containers from the local docker
registry.
make clean-<image_name> must be called to remove an image:
make clean-yocto/kirkstone-qemuarm: remove yocto kirkstone for qemuarm
image

Signed-off-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
---
Changes in v5:
- remove cleaning of all images using make clean
Changes in v4:
- also generate clean rule for CONTAINERS_EXTRA
Changes in v3:
- none
Changes in v2:
- none
Changes in v1:
- patch added
---
 automation/build/Makefile | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/automation/build/Makefile b/automation/build/Makefile
index 72a5335baec1..4cbb1365f94e 100644
--- a/automation/build/Makefile
+++ b/automation/build/Makefile
@@ -28,3 +28,13 @@ all: $(CONTAINERS)
 clean:
        rm -f yocto/*.dockerfiles
 
+define CLEAN_RULE
+.PHONY: clean-$(1)
+clean-$(1):
+ifneq ($$(shell docker image ls -q $(REGISTRY)/$(subst /,:,$(1))),)
+       docker image rm $(REGISTRY)/$(subst /,:,$(1))
+endif
+
+endef
+
+$(eval $(foreach img,$(CONTAINERS) $(CONTAINERS_EXTRA),$(call 
CLEAN_RULE,$(img))))
-- 
2.25.1