Rework devcontainer to use proxygen server

.deploy/built-site.Dockerfile

@@ -1,14 +1,12 @@
 # Creates a docker image with a built copy of the site. Not repo-auth.
 # Useful as a scratch/testing area.
 FROM hhvm/hhvm:4.134-latest
-ARG DOCKER_BUILD_ENV=prod
 ENV TZ UTC
-ENV DEBIAN_FRONTEND noninteractive
 ENV LANG en_US.UTF-8
 ENV LANGUAGE en_US:en
 ENV LC_ALL en_US.UTF-8
 
 RUN rm -rf /var/www
 ADD . /var/www
 
-RUN touch /docker_build && cd /var/www && .deploy/init.sh
+RUN cd /var/www && touch /.docker_build && .deploy/init.sh

.deploy/init.sh

@@ -2,30 +2,18 @@
 
 set -ex
 
-if [ ! -e /docker_build ]; then
+if ! [ -e /.docker_build ]; then
   echo "This script should only be ran from a Dockerfile"
   exit 1
 fi
 
-echo "** Installing apt dependencies"
-# This is done by the dockerfile, but the intermediate issue can be cached, so do
-# it again here.
-apt-get clean
-apt-get update -y
-
-apt-get install -y ruby php-cli zip unzip locales
-
-echo "** Updating locales"
-locale-gen en_US.UTF-8
-
-echo "** Installing composer"
-mkdir /opt/composer
-wget -qO /dev/stdout https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer
-if [ ! -x /usr/local/bin/composer ]; then
-  echo "Failed to install composer"
+if ! [ -x .deploy/system-init.sh ]; then
+  echo "Run from the root directory of the source tree."
   exit 1
 fi
 
+.deploy/system-init.sh
+
 echo "** Installing Hack dependencies"
 composer install
 

.deploy/system-init.sh

@@ -0,0 +1,39 @@
+#!/bin/bash
+
+set -ex
+
+if ! [ -e /.docker_build ]; then
+  echo "This script should only be ran from a Dockerfile"
+  exit 1
+fi
+
+STAMP_FILE=/.hack_docs_system_init.stamp
+if [ -e "$STAMP_FILE" ]; then
+  exit
+fi
+
+export DEBIAN_FRONTEND=noninteractive
+
+echo "** Installing apt dependencies"
+# This is done by the dockerfile, but the intermediate issue can be cached, so do
+# it again here.
+apt-get clean
+apt-get update -y
+
+# Some environments (e.g. VSCode containers) will copy the exterior locale
+# settings, which can break things if the current locale isn't usable in the
+# container; using the `C` locale makes sure that the `locales` package
+# post-install succeeds.
+LC_ALL=C apt-get install -y ruby php-cli zip unzip locales
+
+echo "** Updating locales"
+locale-gen en_US.UTF-8
+
+echo "** Installing composer"
+wget -qO /dev/stdout https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer
+if [ ! -x /usr/local/bin/composer ]; then
+  echo "Failed to install composer"
+  exit 1
+fi
+
+touch "$STAMP_FILE"

.devcontainer/Dockerfile

@@ -0,0 +1,9 @@
+FROM hhvm/hhvm-proxygen:4.134-latest
+
+ARG WORKSPACE
+
+RUN rm -rf /var/www; ln -s ${WORKSPACE} /var/www
+RUN ln -sf /var/www/hhvm.dev.ini /etc/hhvm/site.ini
+
+ADD .deploy/system-init.sh /var/tmp/system-init.sh
+RUN touch /.docker_build && /var/tmp/system-init.sh && rm /var/tmp/system-init.sh

.devcontainer/devcontainer.json

@@ -0,0 +1,34 @@
+{
+  "name": "docs.hhvm.com",
+  "runArgs": [
+    "--init"
+  ],
+  "build": {
+    "dockerfile": "Dockerfile",
+    "args": {
+      "WORKSPACE": "${containerWorkspaceFolder}"
+    },
+    "context": ".."
+  },
+  "runArgs": [
+    "--env", "LC_ALL=C"
+  ],
+  "overrideCommand": false,
+
+  // Set *default* container specific settings.json values on container create.
+  "settings": {
+    "terminal.integrated.profiles.linux": {
+      "bash": {
+        "path": "/bin/bash",
+        "args": [
+          "--login"
+        ]
+      }
+    },
+    "terminal.integrated.defaultProfile.linux": "bash"
+  },
+
+  "extensions": [ "pranayagarwal.vscode-hack" ],
+  "forwardPorts": [ 80 ],
+  "postCreateCommand": ".deploy/init.sh"
+}

src/build/UpdateTagsCLI.hack

@@ -167,7 +167,7 @@ final class UpdateTagsCLI extends CLIBase {
 
     await $stdout->writeAllAsync(" - updating Dockerfiles\n");
     $dockerfiles = \glob(LocalConfig::ROOT.'/.deploy/*.Dockerfile');
-    $dockerfiles[] = LocalConfig::ROOT.'/.devcontainer.json';
+    $dockerfiles[] = LocalConfig::ROOT.'/.devcontainer/Dockerfile';
 
     foreach ($dockerfiles as $path) {
       \file_get_contents($path)