switch to SDK container for builds

Dockerfile

@@ -1,19 +1,7 @@
 # syntax=docker/dockerfile:1.1.3-experimental
 
-FROM fedora:30 AS origin
-RUN dnf makecache && dnf -y update
-
-FROM origin AS base
-RUN dnf -y groupinstall "C Development Tools and Libraries" \
-   && dnf -y install \
-        rpmdevtools dnf-plugins-core createrepo_c \
-        cmake git meson perl-ExtUtils-MakeMaker python which \
-        bc hostname intltool grub2-tools gperf kmod rsync wget \
-        elfutils-devel libcap-devel openssl-devel \
-   && useradd builder
-
-FROM origin AS util
-RUN dnf -y install createrepo_c e2fsprogs gdisk grub2-tools kpartx lz4 veritysetup dosfstools mtools
+ARG SDK
+FROM ${SDK} as sdk
 
 # The experimental cache mount type doesn't expand arguments, so our choices are limited.
 # We can either reuse the same cache for all builds, which triggers overlayfs errors if
@@ -24,11 +12,11 @@ FROM scratch AS cache
 ARG PACKAGE
 ARG ARCH
 # We can't create directories via RUN in a scratch container, so take an existing one.
-COPY --chown=1000:1000 --from=base /tmp /cache
+COPY --chown=1000:1000 --from=sdk /tmp /cache
 # Ensure the ARG variables are used in the layer to prevent reuse by other builds.
 COPY --chown=1000:1000 .dockerignore /cache/.${PACKAGE}.${ARCH}
 
-FROM base AS rpmbuild
+FROM sdk AS rpmbuild
 ARG PACKAGE
 ARG ARCH
 ARG NOCACHE
@@ -70,7 +58,7 @@ RUN --mount=source=.cargo,target=/home/builder/.cargo \
 FROM scratch AS rpm
 COPY --from=rpmbuild /home/builder/rpmbuild/RPMS/*/*.rpm /output/
 
-FROM util AS imgbuild
+FROM sdk AS imgbuild
 ARG PACKAGES
 ARG ARCH
 ARG NOCACHE

Makefile.toml

@@ -15,6 +15,8 @@ DOCKER_BUILDKIT = "1"
 
 [env.development]
 IMAGE = "aws-k8s"
+# Defined here to allow us to override ${BUILDSYS_ARCH} on the command line.
+BUILDSYS_SDK_IMAGE = "thar/sdk-${BUILDSYS_ARCH}:0.0.1"
 # Permit pulling directly Upstream URLs when lookaside cache results in MISSes.
 BUILDSYS_ALLOW_UPSTREAM_SOURCE_URL = "true"
 # Extra flags used when spawning containers.
@@ -28,11 +30,38 @@ script = [
 '''
 mkdir -p ${BUILDSYS_OUTPUT_DIR}
 mkdir -p ${GO_MOD_CACHE}
+
+for cmd in bash curl docker gunzip ; do
+  if ! command -v ${cmd} >/dev/null 2>&1 ; then
+    echo "required program '${cmd}' not found" >&2
+    exit 1
+  fi
+done
 '''
 ]
 
 [tasks.fetch]
-dependencies = ["fetch-workspaces", "fetch-vendored"]
+dependencies = [
+  "fetch-sdk",
+  "fetch-workspaces",
+  "fetch-vendored",
+]
+
+[tasks.fetch-sdk]
+dependencies = ["setup"]
+script_runner = "bash"
+script = [
+'''
+set -o pipefail
+if ! docker image inspect ${BUILDSYS_SDK_IMAGE} >/dev/null 2>&1 ; then
+  if ! curl https://thar-upstream-lookaside-cache.s3.us-west-2.amazonaws.com/${BUILDSYS_SDK_IMAGE}.tar.gz \
+       | gunzip | docker load ; then
+    echo "failed to load '${BUILDSYS_SDK_IMAGE}'" >&2
+    exit 1
+  fi
+fi
+'''
+]
 
 [tasks.fetch-workspaces]
 dependencies = ["setup"]