Add a development container for VS Code (#3343)

* Add a development container config for VS Code

This creates a development environment with a FoundationDB server
and a CouchDB layer in two containers, sharing a network through
Docker Compose.

It uses the FDB image published to Docker Hub for the FDB container,
and downloads the FDB client packages from foundationdb.org to provide
the development headers and libraries. www.foundationdb.org is actually
not trusted in Debian Buster by default, so we have to download the
GeoTrust_Global_CA.pem. The following link has more details:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=962596

Once the Docker Compose setup is running, VS Code executes the
create_cluster_file.bash script to write down a cluster file containing
the IP address in the compose network where the FDB service can be
found. This cluster file is used both for a user-driven invocation of
`./dev/run`, as well as for unit tests that require a running CouchDB.

Additionally, I've got a small fix to the way we run explicitly specified
eunit tests:

* Run eunit tests for each app separately

The `eunit` target executes a for loop that appears intended to use a
separate invocation of rebar for each Erlang application's unit tests.
When running `make eunit` without any arguments this works correctly,
as the for loop processes the output of `ls src`. But if you specify a
comma-delimited list of applications the for loop will treat that as a
single argument and pass it down to rebar. This asymmetry is
surprising, but also seems to cause some issues with environment
variables not being inherited by the environment used to execute the
tests for the 2..N applications in the list. I didn't bother digging
into the rebar source code to figure out what was happening there.

This patch just parses the incoming comma-delimited list with `sed` to
create a whitespace-delimited list for the loop, so we get the same
behavior regardless of whether we are specifying applications
explicitly or not.

7 files changed, 136 insertions, 2 deletions

diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
new file mode 100644
index 000000000..d479bc5a6
--- /dev/null
+++ b/.devcontainer/Dockerfile
@@ -0,0 +1,47 @@
+ARG FDB_VERSION
+ARG ELIXIR_VERSION
+
+# Grab fdbcli and client library from same image as server
+FROM foundationdb/foundationdb:${FDB_VERSION} as fdb
+
+# Debian image with Erlang + Elixir installed (we need elixir for test suite)
+FROM elixir:${ELIXIR_VERSION}
+
+# The FROM directive above sweeps out the ARGs so we need to re-declare here
+# in order to use it again to download the FDB client package
+ARG FDB_VERSION
+
+# Install SpiderMonkey 60 and tell CouchDB to use it in configure
+ARG SM_VSN
+ENV SM_VSN=${SM_VSN:-60}
+
+# Workaround for Debian's temporary lack of trust in FDB Root CA
+RUN set -ex; \
+    wget https://www.geotrust.com/resources/root_certificates/certificates/GeoTrust_Global_CA.pem; \
+    wget --ca-certificate=GeoTrust_Global_CA.pem https://www.foundationdb.org/downloads/${FDB_VERSION}/ubuntu/installers/foundationdb-clients_${FDB_VERSION}-1_amd64.deb; \
+    mkdir /var/lib/foundationdb; \
+    dpkg -i foundationdb-clients_${FDB_VERSION}-1_amd64.deb
+
+# Use NodeSource binaries for Node.js (Fauxton dependency)
+RUN set -ex; \
+    curl -s https://deb.nodesource.com/gpgkey/nodesource.gpg.key | apt-key add -; \
+    echo "deb https://deb.nodesource.com/node_10.x buster main" | tee /etc/apt/sources.list.d/nodesource.list; \
+    echo "deb-src https://deb.nodesource.com/node_10.x buster main" | tee -a /etc/apt/sources.list.d/nodesource.list
+
+RUN set -ex; \
+    apt-get update; \
+    apt-get install -y --no-install-recommends \
+        dnsutils \
+        libmozjs-${SM_VSN}-dev \
+        libicu-dev \
+        python3-venv \
+        python3-pip \
+        python3-sphinx \
+        nodejs
+
+# Documentation theme
+RUN pip3 install sphinx_rtd_theme
+
+COPY --from=fdb /var/fdb/scripts/create_cluster_file.bash /usr/local/bin/
+
+CMD sleep infinity
diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
new file mode 100644
index 000000000..8f7a26d9b
--- /dev/null
+++ b/.devcontainer/devcontainer.json
@@ -0,0 +1,12 @@
+{
+    "dockerComposeFile": "docker-compose.yaml",
+    "service": "couch",
+    "workspaceFolder": "/usr/src/couchdb",
+
+    // Needs to run at start to translate service name into coordinator IP
+    "postStartCommand": ["bash", "/usr/local/bin/create_cluster_file.bash"],
+
+    "extensions": [
+        "erlang-ls.erlang-ls"
+    ]
+}
diff --git a/.devcontainer/docker-compose.yaml b/.devcontainer/docker-compose.yaml
new file mode 100644
index 000000000..79f1da775
--- /dev/null
+++ b/.devcontainer/docker-compose.yaml
@@ -0,0 +1,52 @@
+services:
+  couch:
+    build:
+      context: .
+      dockerfile: Dockerfile
+      args:
+        # Base image for Erlang and Elixir. Useful choices include:
+        # 1.11 -> Erlang 23, Debian Buster
+        # 1.10 -> Erlang 22, Debian Buster
+        # 1.9  -> Erlang 22, Debian Buster
+        #
+        # Older versions based on Debian Stretch will not include
+        # SpiderMonkey 60, which the Dockerfile expects to be able
+        # to install via apt-get.
+        ELIXIR_VERSION: "1.10"
+
+        # SpiderMonkey version to install with apt-get
+        SM_VSN: "60"
+
+        # This should always match the value in fdb.image
+        FDB_VERSION: "6.2.28"
+
+    environment:
+      # This needs to match the name of the FoundationDB service below
+      FDB_COORDINATOR: fdb
+
+      # The location where the Dockerfile installs the FDB cluster file
+      # retrieved from the `fdb` image. CouchDB looks for the cluster file in
+      # this location by default. If you want to install it somewhere else you
+      # you need to change "[erlfdb] cluster_file" and ERL_ZFLAGS to match.
+      FDB_CLUSTER_FILE: /usr/local/etc/foundationdb/fdb.cluster
+
+      # The test suite will default to trying to start its own fdbserver
+      # process. This environment variable tells it to use the fdbserver
+      # running in the `fdb` image instead. Quite a hacky solution. An
+      # alternative might be to parameterize the Makefile so we can swap
+      # `eunit.config` for a `devcontainer.config` via an environment variable
+      # and maintain both config files in the repo.
+      ERL_ZFLAGS: "-erlfdb test_cluster_file <<\\\"/usr/local/etc/foundationdb/fdb.cluster\\\">>"
+
+    volumes:
+      # Mounts the project folder to '/usr/src/couchdb'. The target path inside
+      # the container should match what your application expects. In this case,
+      # the compose file is in a sub-folder, so you will mount '..'. You would
+      # then reference this path as the 'workspaceFolder' in
+      # '.devcontainer/devcontainer.json' so VS Code starts here.
+      - ..:/usr/src/couchdb:cached
+
+    network_mode: service:fdb
+
+  fdb:
+    image: foundationdb/foundationdb:6.2.28
diff --git a/Makefile b/Makefile
index b02f18035..95d5bf60d 100644
--- a/Makefile
+++ b/Makefile
@@ -152,7 +152,7 @@ check-all-tests: all python-black
 	@$(MAKE) elixir
 
 ifdef apps
-subdirs = $(apps)
+subdirs=$(shell echo $(apps) | sed 's/,/ /g')
 else
 subdirs=$(shell ls src)
 endif
diff --git a/configure b/configure
index 0793d6837..0cfb469b0 100755
--- a/configure
+++ b/configure
@@ -29,7 +29,7 @@ ERLANG_MD5="false"
 SKIP_DEPS=0
 
 COUCHDB_USER="$(whoami 2>/dev/null || echo couchdb)"
-SM_VSN="1.8.5"
+SM_VSN=${SM_VSN:-"1.8.5"}
 ARCH="$(uname -m)"
 
 . ${rootdir}/version.mk
diff --git a/erlang_ls.config b/erlang_ls.config
new file mode 100644
index 000000000..ffc769e1b
--- /dev/null
+++ b/erlang_ls.config
@@ -0,0 +1,10 @@
+include_dirs:
+    - "src/"
+    - "src/*/include/"
+macros:
+    - name: COUCHDB_VERSION
+      value: erlangls
+    - name: COUCHDB_GIT_SHA
+      value: deadbeef
+    - name: AEGIS_KEY_MANAGER
+      value: aegis_noop_key_manager
diff --git a/rel/files/eunit.config b/rel/files/eunit.config
index 5e96fae9e..4e49c6d17 100644
--- a/rel/files/eunit.config
+++ b/rel/files/eunit.config
@@ -13,5 +13,18 @@
 [
     {kernel, [{error_logger, silent}]},
     {sasl, [{sasl_error_logger, false}]},
+
+    % When fabric is configured with eunit_run=true it will ask erlfdb for a
+    % test database. The default behavior for erlfdb in this case is start a
+    % new fdbserver process for the test. If you would rather have erlfdb
+    % connect to an existing FoundationDB cluster, you can supply the path
+    % to the cluster file as a binary string here.
+    %
+    % NOTE: the unit tests will erase all the data in the cluster!
+    %
+    % The docker-compose configuration in the .devcontainer activates this
+    % application setting using ERL_ZFLAGS in the container environment, so
+    % any tests will use the fdbserver running in the fdb container.
+    % {erlfdb, [{test_cluster_file, <<"/usr/local/etc/foundationdb/fdb.cluster">>}]},
     {fabric, [{eunit_run, true}]}
 ].