Speed up DNF during image builds

Containerfile

@@ -43,6 +43,7 @@ COPY system_files /system_files/
 
 FROM quay.io/fedora/fedora-bootc:44
 ARG ARMADA_VERSION=unknown
+ARG ARMADA_FEDORA_MIRROR=
 LABEL org.opencontainers.image.version="${ARMADA_VERSION}"
 
 RUN --mount=type=bind,from=ctx,source=/,target=/ctx \
@@ -66,6 +67,7 @@ RUN --mount=type=bind,from=ctx,source=/,target=/ctx \
     --mount=type=tmpfs,dst=/tmp \
     mkdir -p /usr/lib/armada && \
     printf '%s\n' "${ARMADA_VERSION}" >/usr/lib/armada/version && \
+    export ARMADA_FEDORA_MIRROR="${ARMADA_FEDORA_MIRROR}" && \
     /ctx/build_files/build.sh
 
 RUN bootc container lint

Justfile

@@ -82,6 +82,9 @@ build $target_image=image_name $tag=default_tag:
     BUILD_ARGS=()
     ARMADA_VERSION="$(TZ=America/New_York date +%Y%m%d).$(git rev-parse --short HEAD)"
     BUILD_ARGS+=("--build-arg" "ARMADA_VERSION=${ARMADA_VERSION}")
+    if [[ -n "${ARMADA_FEDORA_MIRROR:-}" ]]; then
+        BUILD_ARGS+=("--build-arg" "ARMADA_FEDORA_MIRROR=${ARMADA_FEDORA_MIRROR}")
+    fi
 
     # Allow local armada-packages images to override pinned package images.
     mapfile -t PKG_VARS < <(sed -n 's/^ARG \([A-Z0-9_]*_PKG\)=.*/\1/p' Containerfile)

build_files/05-configure-dnf.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+set -euxo pipefail
+
+BUILD_DNF_STATE_DIR=/tmp/armada-build-dnf
+
+mkdir -p /etc/dnf/libdnf5.conf.d
+cat >/etc/dnf/libdnf5.conf.d/10-armada-build.conf <<'EOF'
+[main]
+fastestmirror=True
+max_parallel_downloads=10
+minrate=200k
+timeout=20
+EOF
+
+if [[ -n "${ARMADA_FEDORA_MIRROR:-}" ]]; then
+    fedora_mirror="${ARMADA_FEDORA_MIRROR%/}"
+    mkdir -p "${BUILD_DNF_STATE_DIR}/yum.repos.d"
+
+    for repo in /etc/yum.repos.d/fedora*.repo; do
+        [[ -e "${repo}" ]] || continue
+        grep -q '^#baseurl=http://download.example/pub/fedora/linux' "${repo}" || continue
+        cp -a "${repo}" "${BUILD_DNF_STATE_DIR}/yum.repos.d/${repo##*/}"
+        sed -i \
+            -e 's|^metalink=|#metalink=|' \
+            -e "s|^#baseurl=http://download.example/pub/fedora/linux|baseurl=${fedora_mirror}|" \
+            "${repo}"
+    done
+fi

build_files/75-restore-build-dnf.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+set -euxo pipefail
+
+BUILD_DNF_STATE_DIR=/tmp/armada-build-dnf
+
+rm -f /etc/dnf/libdnf5.conf.d/10-armada-build.conf
+
+if [[ -d "${BUILD_DNF_STATE_DIR}/yum.repos.d" ]]; then
+    for repo in "${BUILD_DNF_STATE_DIR}"/yum.repos.d/*.repo; do
+        [[ -e "${repo}" ]] || continue
+        cp -a "${repo}" "/etc/yum.repos.d/${repo##*/}"
+    done
+fi
+
+rm -rf "${BUILD_DNF_STATE_DIR}"

build_files/build.sh

@@ -3,6 +3,7 @@ set -euxo pipefail
 
 cd /ctx/build_files
 
+./05-configure-dnf.sh
 ./10-base-packages.sh
 ./20-install-kernel.sh
 ./30-install-steam-session.sh
@@ -12,4 +13,5 @@ cd /ctx/build_files
 ./55-generate-initramfs.sh
 ./60-set-default-target.sh
 ./70-cleanup.sh
+./75-restore-build-dnf.sh
 ./80-finalize-update-state.sh