Move Rack SDK outside of Docker image to allow updating Rack SDK without rebuilding Docker image.

.gitignore

@@ -1,5 +1,5 @@
 MacOSX*.sdk.tar.*
 local/
 plugin-build/
-Rack-SDK/
+Rack-SDK-*/
 osxcross/

Dockerfile

@@ -32,9 +32,4 @@ RUN JOBS=$JOBS make toolchain-mac
 RUN JOBS=$JOBS make toolchain-win
 RUN JOBS=$JOBS make toolchain-lin
 
-# Install Rack SDK
-RUN make -j $JOBS rack-sdk-mac
-RUN make -j $JOBS rack-sdk-win
-RUN make -j $JOBS rack-sdk-lin
-
 RUN rm MacOSX11.1.sdk.tar.*

Makefile

@@ -17,10 +17,10 @@ export JOBS_CT_NG :=
 endif
 
 RACK_SDK_VERSION := 2.1.2
+DOCKER_IMAGE_VERSION := 3
 
 all: toolchain-all
 
-
 # Toolchain build
 
 
@@ -114,8 +114,12 @@ $(rack-sdk-lin):
 	rm Rack-SDK-$(RACK_SDK_VERSION)-lin.zip
 RACK_DIR_LIN := $(PWD)/$(rack-sdk-lin)
 
+rack-sdk-clean:
+	rm -rf $(PWD)/Rack-SDK-mac $(PWD)/Rack-SDK-win $(PWD)/Rack-SDK-lin
+
+rack-sdk-all: rack-sdk-mac rack-sdk-win rack-sdk-lin
 
-toolchain-all: toolchain-lin toolchain-win toolchain-mac rack-sdk-mac rack-sdk-win rack-sdk-lin
+toolchain-all: toolchain-lin toolchain-win toolchain-mac rack-sdk-all
 
 
 toolchain-clean:
@@ -223,15 +227,18 @@ dep-arch-linux:
 		help2man
 
 
-docker-build:
-	docker build --build-arg JOBS=$(JOBS) --tag rack-plugin-toolchain:2 .
+docker-build: rack-sdk-all
+	docker build --build-arg JOBS=$(JOBS) --tag rack-plugin-toolchain:$(DOCKER_IMAGE_VERSION) .
 
 
 DOCKER_RUN := docker run --rm --interactive --tty \
 	--volume=$(PLUGIN_DIR):/home/build/plugin-src \
 	--volume=$(PWD)/$(PLUGIN_BUILD_DIR):/home/build/rack-plugin-toolchain/$(PLUGIN_BUILD_DIR) \
+	--volume=$(PWD)/Rack-SDK-mac:/home/build/rack-plugin-toolchain/Rack-SDK-mac \
+	--volume=$(PWD)/Rack-SDK-win:/home/build/rack-plugin-toolchain/Rack-SDK-win \
+	--volume=$(PWD)/Rack-SDK-lin:/home/build/rack-plugin-toolchain/Rack-SDK-lin \
 	--env PLUGIN_DIR=/home/build/plugin-src \
-	rack-plugin-toolchain:2 \
+	rack-plugin-toolchain:$(DOCKER_IMAGE_VERSION) \
 	/bin/bash
 
 docker-run:

README.md

@@ -68,6 +68,19 @@ You may replace 8 with your desired number of parallel jobs, such as your number
 
 Built plugin packages are placed in the `plugin-build/` directory.
 
+### Rack SDK management
+
+The latest Rack SDKs for all supported platforms are downloaded during the toolchain build.
+
+The SDKs can be updated to the latest version (defined in the `Makefile`) as follows:
+
+```
+make rack-sdk-clean
+make rack-sdk-all
+```
+
+This is especially convenient for the Docker-based toolchain, because it does not require to rebuild the entire toolchain to update to the latest SDK.
+
 ## Acknowledgments
 
 Thanks to @cschol for help with crosstool-ng, Ubuntu, Docker, and testing.