tools: support http-proxy only network environments in environment-setup

Currently the environment-setup script would fail in network environments
that can only access the internet via an HTTP(S) proxy service, this patch
implement the necessary logic to support such situations via setting the
proper LXD configuration and environment variables in the snapcraft-dev
container.

Signed-off-by: 林博仁(Buo-ren, Lin) <Buo.Ren.Lin@gmail.com>

tools/environment-setup.sh

@@ -8,6 +8,62 @@ if ! grep -q '^name: snapcraft$' "${SNAPCRAFT_DIR}/snap/snapcraft.yaml"; then
     exit 1
 fi
 
+# Check whether the user may be in an HTTP(S) proxy only network.
+http_proxy_detected=
+if test -v HTTP_PROXY || test -v http_proxy; then
+    printf \
+        'HTTP proxy environment detected, configuring LXD HTTP proxy settings...\n'
+    for env_name in HTTP_PROXY http_proxy; do
+        if test -v "${env_name}"; then
+            http_proxy_detected="${!env_name}"
+            break
+        fi
+    done
+
+    if ! lxc_config_proxy_http="$(lxc config get core.proxy_http)"; then
+        printf \
+            'Unable to query the value of the core.proxy_http LXD server configuration.\n' \
+            1>&2
+        exit 1
+    fi
+
+    if test "${lxc_config_proxy_http}" != "${http_proxy_detected}"; then
+        if ! lxc config set core.proxy_http="${http_proxy_detected}"; then
+            printf \
+                'Error: Unable to set the value of the core.proxy_http LXD server configuration.\n' \
+                1>&2
+            exit 1
+        fi
+    fi
+fi
+
+https_proxy_detected=
+if test -v HTTPS_PROXY || test -v https_proxy; then
+    printf 'HTTPS proxy environment detected, configuring LXD HTTPS proxy settings...\n'
+    for env_name in HTTPS_PROXY https_proxy; do
+        if test -v "${env_name}"; then
+            https_proxy_detected="${!env_name}"
+            break
+        fi
+    done
+
+    if ! lxc_config_proxy_https="$(lxc config get core.proxy_https)"; then
+        printf \
+            'Error: Unable to query the value of the core.proxy_https LXD server configuration.\n' \
+            1>&2
+        exit 1
+    fi
+
+    if test "${lxc_config_proxy_https}" != "${https_proxy_detected}"; then
+        if ! lxc config set core.proxy_https="${https_proxy_detected}"; then
+            printf \
+                'Error: Unable to set the value of the core.proxy_https LXD server configuration.\n' \
+                1>&2
+            exit 1
+        fi
+    fi
+fi
+
 # Create the container.
 if ! lxc info snapcraft-dev >/dev/null 2>&1; then
     lxc init ubuntu:20.04 snapcraft-dev
@@ -32,6 +88,53 @@ if ! lxc config device show snapcraft-dev | grep -q snapcraft-project; then
         source="$SNAPCRAFT_DIR" path=/home/ubuntu/snapcraft
 fi
 
+# Set proxy on login.
+if test -n "${http_proxy_detected}"; then
+    lxc exec snapcraft-dev -- sudo -iu ubuntu bash -c \
+        "echo 'export HTTP_PROXY=${http_proxy_detected}' >> .profile"
+    lxc exec snapcraft-dev -- sudo -iu ubuntu bash -c \
+        "echo 'export http_proxy=${http_proxy_detected}' >> .profile"
+fi
+if test -n "${https_proxy_detected}"; then
+    lxc exec snapcraft-dev -- sudo -iu ubuntu bash -c \
+        "echo 'export HTTPS_PROXY=${https_proxy_detected}' >> .profile"
+    lxc exec snapcraft-dev -- sudo -iu ubuntu bash -c \
+        "echo 'export https_proxy=${https_proxy_detected}' >> .profile"
+fi
+
+# Tell sudo to passthrough the proxy related environment variables
+if ! temp_dir="$(mktemp -dt snapcraft.XXXXXX)"; then
+    printf 'Error: Unable to create the temporary directory.\n' 1>&2
+    exit 1
+fi
+trap 'rm -rf "${temp_dir}"' EXIT
+
+# Configure snapd to use the HTTP(S) proxy
+if test -n "${http_proxy_detected}"; then
+    lxc exec snapcraft-dev -- \
+        sudo snap set system proxy.http="${http_proxy_detected}"
+fi
+
+if test -n "${https_proxy_detected}"; then
+    lxc exec snapcraft-dev -- \
+        sudo snap set system proxy.https="${https_proxy_detected}"
+fi
+
+printf \
+    'Defaults env_keep += "HTTP_PROXY http_proxy HTTPS_PROXY https_proxy"\n' \
+    >"${temp_dir}/allow-http-proxy"
+if ! \
+    lxc file push \
+        --uid 0 \
+        --gid 0 \
+        --mode 0640 \
+        "${temp_dir}/allow-http-proxy" \
+        snapcraft-dev/etc/sudoers.d/allow-http-proxy; then
+    printf \
+        'Error: Unable to install the sudo security policy drop-in file for allowing HTTP(S) proxy environment variables to pass-through.\n' \
+        1>&2
+fi
+
 # Install snapcraft and dependencies.
 lxc exec snapcraft-dev -- sudo -iu ubuntu /home/ubuntu/snapcraft/tools/environment-setup-local.sh