fix(Dockerfile): implement fallback mechanisms for apt update and install

Dockerfile

@@ -41,8 +41,25 @@ if url:
         finally:
             sock.close()
 PY
+APT_PROXY_CONFIG=/etc/apt/apt.conf.d/01proxy
+
+apt_update_with_fallback() {
+    if ! apt-get update; then
+        rm -f "$APT_PROXY_CONFIG"
         apt-get update
-apt-get install -y --no-install-recommends build-essential gcc libpq-dev
+    fi
+}
+
+apt_install_with_fallback() {
+    if ! apt-get install -y --no-install-recommends "$@"; then
+        rm -f "$APT_PROXY_CONFIG"
+        apt-get update
+        apt-get install -y --no-install-recommends "$@"
+    fi
+}
+
+apt_update_with_fallback
+apt_install_with_fallback build-essential gcc libpq-dev
 pip install --upgrade pip
 pip wheel --no-deps --wheel-dir /wheels -r requirements.txt
 apt-get purge -y --auto-remove build-essential gcc
@@ -88,8 +105,25 @@ if url:
         finally:
             sock.close()
 PY
+APT_PROXY_CONFIG=/etc/apt/apt.conf.d/01proxy
+
+apt_update_with_fallback() {
+    if ! apt-get update; then
+        rm -f "$APT_PROXY_CONFIG"
         apt-get update
-apt-get install -y --no-install-recommends libpq5
+    fi
+}
+
+apt_install_with_fallback() {
+    if ! apt-get install -y --no-install-recommends "$@"; then
+        rm -f "$APT_PROXY_CONFIG"
+        apt-get update
+        apt-get install -y --no-install-recommends "$@"
+    fi
+}
+
+apt_update_with_fallback
+apt_install_with_fallback libpq5
 rm -rf /var/lib/apt/lists/*
 EOF