makefile.toml: one workspace and cargo metadata

For kit builds, Buildsys will need to understand the cargo dependency
graph. This requires a call to cargo metadata which, for efficiency
sake, we do only once before calling cargo build. This commit updates
Makefile.toml to provide that information to Buildsys.

Additionally, we want to have one workspace at the top-level of the
Twoliter project which includes all packages, kits and variants.
This commit also includes changes to the Makefile.toml to support a
single workspace.

Author: webern

twoliter/embedded/Makefile.toml

@@ -1,5 +1,6 @@
 [config]
 skip_core_tasks = true
+default_to_workspace = false
 
 [env]
 # The directory into which Twoliter has installed tools (e.g. buildsys,
@@ -15,6 +16,8 @@ BUILDSYS_IMAGES_DIR = "${BUILDSYS_BUILD_DIR}/images"
 BUILDSYS_TOOLS_DIR = "${BUILDSYS_ROOT_DIR}/tools"
 BUILDSYS_SOURCES_DIR = "${BUILDSYS_ROOT_DIR}/sources"
 BUILDSYS_SBKEYS_DIR = "${BUILDSYS_ROOT_DIR}/sbkeys"
+BUILDSYS_METADATA_DIR = "${BUILDSYS_BUILD_DIR}/metadata"
+BUILDSYS_CARGO_METADATA_PATH = "${BUILDSYS_METADATA_DIR}/cargo_metadata.json"
 BUILDSYS_SBKEYS_PROFILE = { script = ['echo "${BUILDSYS_SBKEYS_PROFILE:-local}"'] }
 BUILDSYS_TIMESTAMP = { script = ["date +%s"] }
 BUILDSYS_VERSION_BUILD = { script = ["git describe --always --dirty --exclude '*' || echo 00000000"] }
@@ -278,6 +281,7 @@ mkdir -p ${BUILDSYS_BUILD_DIR}
 mkdir -p ${BUILDSYS_OUTPUT_DIR}
 mkdir -p ${BUILDSYS_PACKAGES_DIR}
 mkdir -p ${BUILDSYS_STATE_DIR}
+mkdir -p ${BUILDSYS_METADATA_DIR}
 mkdir -p ${GO_MOD_CACHE}
 '''
 ]
@@ -321,10 +325,12 @@ dependencies = ["setup"]
 script_runner = "bash"
 script = [
 '''
-for ws in sources variants; do
-  [ -d "${ws}" ] || continue
-  cargo fetch --locked --manifest-path ${ws}/Cargo.toml
-done
+if [ -f "${BUILDSYS_SOURCES_DIR}/Cargo.toml" ]; then
+  cargo fetch --locked --manifest-path "${BUILDSYS_SOURCES_DIR}/Cargo.toml"
+fi
+
+cargo fetch --locked --manifest-path "${BUILDSYS_ROOT_DIR}/Cargo.toml"
+
 chmod -R o+r ${CARGO_HOME}
 '''
 ]
@@ -727,9 +733,26 @@ docker run --rm \
 '''
 ]
 
+# Reads the project's workspace Cargo dependency graph to a json file. Needed by buildsys when
+# building packages, kits and variants.
+[tasks.cargo-metadata]
+dependencies = ["setup"]
+script_runner = "bash"
+script = [
+'''
+rm -f "${BUILDSYS_CARGO_METADATA_PATH}"
+cargo metadata \
+  --format-version 1 \
+  --manifest-path "${BUILDSYS_ROOT_DIR}/Cargo.toml" \
+  --offline \
+  --all-features \
+  > "${BUILDSYS_CARGO_METADATA_PATH}"
+'''
+]
+
 # Builds a package including its build-time and runtime dependency packages.
 [tasks.build-package]
-dependencies = ["check-cargo-version", "fetch-sdk", "publish-setup", "fetch-licenses"]
+dependencies = ["check-cargo-version", "fetch-sdk", "publish-setup", "fetch-licenses", "cargo-metadata"]
 script_runner = "bash"
 script = [
 '''
@@ -757,13 +780,12 @@ cargo build \
   ${CARGO_BUILD_ARGS} \
   ${CARGO_MAKE_CARGO_ARGS} \
   ${CARGO_MAKE_CARGO_LIMIT_JOBS} \
-  --manifest-path "variants/Cargo.toml" \
-  --package "${PACKAGE}"
+  --manifest-path "${BUILDSYS_ROOT_DIR}/packages/${PACKAGE}/Cargo.toml"
 '''
 ]
 
 [tasks.build-variant]
-dependencies = ["fetch-sdk", "build-sbkeys", "publish-setup"]
+dependencies = ["fetch-sdk", "build-sbkeys", "publish-setup", "cargo-metadata"]
 script = [
 '''
 export PATH="${TWOLITER_TOOLS_DIR}:${PATH}"
@@ -777,7 +799,7 @@ export BUILDSYS_VARIANT_FLAVOR="${BUILDSYS_VARIANT_FLAVOR}"
 
 # Save built artifacts for each architecture.  We don't set this everywhere
 # because we build host tools with cargo as well, like buildsys and pubsys.
-export CARGO_TARGET_DIR=${BUILDSYS_ROOT_DIR}/variants/target/${BUILDSYS_ARCH}
+export CARGO_TARGET_DIR=${BUILDSYS_ROOT_DIR}/target/${BUILDSYS_ARCH}
 
 rm -rf "${BUILDSYS_OUTPUT_DIR}/latest"
 cargo build \
@@ -1471,16 +1493,20 @@ dependencies = [
   "clean-repos",
   "clean-state",
   "clean-tools",
+  "clean-metadata",
 ]
 
 [tasks.clean-sources]
 script_runner = "bash"
 script = [
 '''
-for ws in sources; do
-  [ -d "${ws}" ] || continue
-  cargo clean --manifest-path ${ws}/Cargo.toml
-done
+
+if [ -f "${BUILDSYS_SOURCES_DIR}/Cargo.toml" ]; then
+    cargo clean --manifest-path "${BUILDSYS_SOURCES_DIR}/Cargo.toml"
+fi
+
+cargo clean --manifest-path "${BUILDSYS_ROOT_DIR}/Cargo.toml"
+
 rm -f ${BUILDSYS_TOOLS_DIR}/bin/*
 '''
 ]
@@ -1489,10 +1515,6 @@ rm -f ${BUILDSYS_TOOLS_DIR}/bin/*
 script_runner = "bash"
 script = [
 '''
-for ws in variants; do
-  [ -d "${ws}" ] || continue
-  cargo clean --manifest-path ${ws}/Cargo.toml
-done
 rm -rf ${BUILDSYS_PACKAGES_DIR}
 '''
 ]
@@ -1531,6 +1553,14 @@ fi
 '''
 ]
 
+[tasks.clean-metadata]
+script_runner = "bash"
+script = [
+'''
+rm -rf "${BUILDSYS_METADATA_DIR}"
+'''
+]
+
 # Deletes cached code used for Bottlerocket builds
 [tasks.purge-cache]
 dependencies = [