Apt proxy fallback

README.md

@@ -95,6 +95,10 @@ The following environment variables are supported:
        docker-compose up -d
        echo 'APT_PROXY=http://172.17.0.1:3142' >> config
 
+ * `APT_PROXY_FALLBACK` (Default: unset)
+
+   Setting this option to `1` will make apt fallback to direct connection when proxy connection fails.
+
  * `BASE_DIR`  (Default: location of `build.sh`)
 
    **CAUTION**: Currently, changing this value will probably break build.sh

build.sh

@@ -236,6 +236,7 @@ export PUBKEY_SSH_FIRST_USER
 export CLEAN
 export IMG_NAME
 export APT_PROXY
+export APT_PROXY_FALLBACK
 
 export STAGE
 export STAGE_DIR
@@ -280,9 +281,11 @@ if [[ ! "$FIRST_USER_NAME" =~ ^[a-z][-a-z0-9_]*$ ]]; then
 	exit 1
 fi
 
-if [[ -n "${APT_PROXY}" ]] && ! curl --silent "${APT_PROXY}" >/dev/null ; then
-	echo "Could not reach APT_PROXY server: ${APT_PROXY}"
-	exit 1
+if ! proxy_check; then
+	if [[ "${APT_PROXY_FALLBACK}" != "1" ]]; then
+		echo "Could not reach APT_PROXY server: ${APT_PROXY}"
+		exit 1
+	fi
 fi
 
 if [[ -n "${WPA_PASSWORD}" && ${#WPA_PASSWORD} -lt 8 || ${#WPA_PASSWORD} -gt 63  ]] ; then

export-image/01-set-sources/01-run.sh

@@ -1,6 +1,8 @@
 #!/bin/bash -e
 
 rm -f "${ROOTFS_DIR}/etc/apt/apt.conf.d/51cache"
+rm -f "${ROOTFS_DIR}/etc/apt/apt.conf.d/52fallback"
+rm -f "${ROOTFS_DIR}/bin/detect-proxy"
 find "${ROOTFS_DIR}/var/lib/apt/lists/" -type f -delete
 on_chroot << EOF
 apt-get update

scripts/common

@@ -7,13 +7,16 @@ bootstrap(){
 	local BOOTSTRAP_CMD=debootstrap
 	local BOOTSTRAP_ARGS=()
 
-	export http_proxy=${APT_PROXY}
-
+	if proxy_check; then
+		export http_proxy=${APT_PROXY} 
+	fi
+
 	BOOTSTRAP_ARGS+=(--arch armhf)
 	BOOTSTRAP_ARGS+=(--components "main,contrib,non-free")
 	BOOTSTRAP_ARGS+=(--keyring "${STAGE_DIR}/files/raspberrypi.gpg")
 	BOOTSTRAP_ARGS+=(--exclude=info)
 	BOOTSTRAP_ARGS+=(--include=ca-certificates)
+	BOOTSTRAP_ARGS+=(--include=curl)
 	BOOTSTRAP_ARGS+=("$@")
 	printf -v BOOTSTRAP_STR '%q ' "${BOOTSTRAP_ARGS[@]}"
 
@@ -98,3 +101,12 @@ update_issue() {
 	echo -e "Raspberry Pi reference ${IMG_DATE}\nGenerated using ${PI_GEN}, ${PI_GEN_REPO}, ${GIT_HASH}, ${1}" > "${ROOTFS_DIR}/etc/rpi-issue"
 }
 export -f update_issue
+
+proxy_check(){
+    if [[ -n "${APT_PROXY}" ]] && ! curl --silent "${APT_PROXY}" >/dev/null ; then
+	    return 1
+    else
+        return 0
+    fi
+}
+export -f proxy_check

stage0/00-configure-apt/00-run.sh

@@ -6,10 +6,21 @@ sed -i "s/RELEASE/${RELEASE}/g" "${ROOTFS_DIR}/etc/apt/sources.list"
 sed -i "s/RELEASE/${RELEASE}/g" "${ROOTFS_DIR}/etc/apt/sources.list.d/raspi.list"
 
 if [ -n "$APT_PROXY" ]; then
-	install -m 644 files/51cache "${ROOTFS_DIR}/etc/apt/apt.conf.d/51cache"
-	sed "${ROOTFS_DIR}/etc/apt/apt.conf.d/51cache" -i -e "s|APT_PROXY|${APT_PROXY}|"
+	if [ "$APT_PROXY_FALLBACK" == "1" ]; then
+		install -m 644 files/52fallback "${ROOTFS_DIR}/etc/apt/apt.conf.d/52fallback"
+		install -m 755 files/detect-proxy "${ROOTFS_DIR}/bin/detect-proxy"
+		sed "${ROOTFS_DIR}/bin/detect-proxy" -i -e "s|APT_PROXY|${APT_PROXY}|"
+	else
+		install -m 644 files/51cache "${ROOTFS_DIR}/etc/apt/apt.conf.d/51cache"
+		sed "${ROOTFS_DIR}/etc/apt/apt.conf.d/51cache" -i -e "s|APT_PROXY|${APT_PROXY}|"
+
+		rm -f "${ROOTFS_DIR}/etc/apt/apt.conf.d/52fallback"
+		rm -f "${ROOTFS_DIR}/bin/detect-proxy"
+	fi
 else
 	rm -f "${ROOTFS_DIR}/etc/apt/apt.conf.d/51cache"
+	rm -f "${ROOTFS_DIR}/etc/apt/apt.conf.d/52fallback"
+	rm -f "${ROOTFS_DIR}/bin/detect-proxy"
 fi
 
 cat files/raspberrypi.gpg.key | gpg --dearmor > "${ROOTFS_DIR}/etc/apt/trusted.gpg.d/raspberrypi-archive-stable.gpg"

stage0/00-configure-apt/files/52fallback

@@ -0,0 +1 @@
+Acquire::http::Proxy-Auto-Detect "/bin/detect-proxy";

stage0/00-configure-apt/files/detect-proxy

@@ -0,0 +1,6 @@
+#!/bin/bash
+if curl --silent "APT_PROXY" >/dev/null; then
+    echo -n "APT_PROXY"
+else
+    echo -n "DIRECT"
+fi