Set up Docker build and CI to get the version build right

Dockerfile

@@ -18,6 +18,11 @@ FROM base AS build
 ARG THREADS=8
 ARG TARGETARCH
 
+# If you didn't `make version` berfore building the Docker, you can provide a
+# version value here to claim to be.
+ARG VG_GIT_VERSION
+ENV VG_GIT_VERSION=${VG_GIT_VERSION:-unknown}
+
 RUN echo build > /stage.txt
 
 RUN apt-get -qq -y update && \
@@ -56,22 +61,13 @@ RUN find . -name CMakeCache.txt | xargs rm -f
 COPY Makefile /vg/Makefile
 RUN . ./source_me.sh && CXXFLAGS="$(if [ -z "${TARGETARCH}" ] || [ "${TARGETARCH}" = "amd64" ] ; then echo " -march=nehalem "; fi)" CFLAGS="$(if [ -z "${TARGETARCH}" ] || [ "${TARGETARCH}" = "amd64" ] ; then echo " -march=nehalem "; fi)" make -j $((THREADS < $(nproc) ? THREADS : $(nproc))) deps
 
-# Bring in the sources, which we need in order to build
+# Bring in the sources, which we need in order to build.
 COPY src /vg/src
 
 # Build all the object files for vg, but don't link.
 # Also pass the arch here
 RUN . ./source_me.sh && CXXFLAGS="$(if [ -z "${TARGETARCH}" ] || [ "${TARGETARCH}" = "amd64" ] ; then echo " -march=nehalem "; fi)" make -j $((THREADS < $(nproc) ? THREADS : $(nproc))) objs
 
-# Bring in any includes we pre-made, like the git version, if present
-COPY include /vg/include
-
-# Make sure version introspection is up to date
-RUN rm -f obj/version.o && . ./source_me.sh && CXXFLAGS="$(if [ -z "${TARGETARCH}" ] || [ "${TARGETARCH}" = "amd64" ] ; then echo " -march=nehalem "; fi)" make -j $((THREADS < $(nproc) ? THREADS : $(nproc))) obj/version.o
-
-# Announce the version file, which must exist by now
-RUN ls /vg/include && cat /vg/include/vg_git_version.hpp
-
 # Do the final build and link, knowing the version. Trim down the resulting binary but make sure to include enough debug info for profiling.
 RUN . ./source_me.sh && CXXFLAGS="$(if [ -z "${TARGETARCH}" ] || [ "${TARGETARCH}" = "amd64" ] ; then echo " -march=nehalem "; fi)" make -j $((THREADS < $(nproc) ? THREADS : $(nproc))) static && strip -d bin/vg
 

Makefile

@@ -474,7 +474,7 @@ DEPS += $(INC_DIR)/BooPHF.h
 DEPS += $(INC_DIR)/mio/mmap.hpp
 DEPS += $(INC_DIR)/atomic_queue.h
 
-.PHONY: clean clean-tests get-deps deps test set-path objs static static-docker docs man .pre-build
+.PHONY: clean clean-tests get-deps deps test set-path objs static static-docker docs man .pre-build version
 
 # Aggregate all libvg deps, and exe deps other than libvg
 LIBVG_DEPS = $(OBJ) $(ALGORITHMS_OBJ) $(IO_OBJ) $(DEP_OBJ) $(DEPS)
@@ -866,8 +866,10 @@ $(LIB_DIR)/libxg.a: $(XG_DIR)/src/*.hpp $(XG_DIR)/src/*.cpp $(INC_DIR)/mmmultima
 
 # Auto-git-versioning
 
-# We need to scope this variable here
-GIT_VERSION_FILE_DEPS =
+# Can be overridden from the environment to supply a version if none is on disk.
+VG_GIT_VERSION ?= unknown
+# Clean old path
+$(shell rm -f $(INC_DIR)/vg_git_version.hpp)
 # Decide if .git exists and needs to be watched
 ifeq ($(shell if [ -d .git ]; then echo present; else echo absent; fi),present)
     # If so, try and make a git version file.
@@ -879,19 +881,20 @@ ifeq ($(shell if [ -d .git ]; then echo present; else echo absent; fi),present)
     # If it's not the same as the old one, replace the old one.
     # If it is the same, do nothing and don't rebuild dependent targets.
     $(info Check Git)
-    # Clean old path
-    $(shell rm -f $(INC_DIR)/vg_git_version.hpp)
     $(shell echo "#define VG_GIT_VERSION \"$(shell git describe --always --tags 2>/dev/null || echo git-error)\"" > $(SRC_DIR)/vg_git_version.hpp.tmp)
-    $(shell diff $(SRC_DIR)/vg_git_version.hpp.tmp $(SRC_DIR)/vg_git_version.hpp >/dev/null 2>/dev/null || cp $(SRC_DIR)/vg_git_version.hpp.tmp $(SRC_DIR)/vg_git_version.hpp)
-    $(shell rm -f $(SRC_DIR)/vg_git_version.hpp.tmp)
+	$(shell diff $(SRC_DIR)/vg_git_version.hpp.tmp $(SRC_DIR)/vg_git_version.hpp >/dev/null 2>/dev/null || cp $(SRC_DIR)/vg_git_version.hpp.tmp $(SRC_DIR)/vg_git_version.hpp)
+	$(shell rm -f $(SRC_DIR)/vg_git_version.hpp.tmp)
 else
-    # Just use the version file we have, if any
+    # Just use the version file we have, if any.
     $(info Do not check Git)
-    # Clean old path
-    $(shell rm -f $(INC_DIR)/vg_git_version.hpp)
-    $(shell if [ ! -e $(SRC_DIR)/vg_git_version.hpp ]; then touch $(SRC_DIR)/vg_git_version.hpp; fi;)
+	$(shell if [ ! -e $(SRC_DIR)/vg_git_version.hpp] ; then echo "#define VG_GIT_VERSION \"$(VG_GIT_VERSION)\"" > $(SRC_DIR)/vg_git_version.hpp ; fi)
 endif
 
+
+# We have a do-nothing target so we can "make version"
+version:
+	@echo "Version information up to date"
+
 # Build an environment version file.
 # If it's not the same as the old one, replace the old one.
 # If it is the same, do nothing and don't rebuild dependent targets.

vgci/vgci.sh

@@ -266,9 +266,9 @@ then
         # have priveleges to easily install dependencies
 
         # Build the git version file first, so the Docker knows its version
-        make include/vg_git_version.hpp
+        make version
 
-        docker pull ubuntu:18.04
+        docker pull mirror.gcr.io/library/ubuntu:20.04
         docker build --no-cache -t "${DOCKER_TAG}" -f Dockerfile .
         if [ "$?" -ne 0 ]
         then