ci: add hello-debian example (#101)

Adds an example that runs in a `debian:bookworm` container.

Author: cwaldren-ld

.github/workflows/ci.yml

@@ -42,7 +42,7 @@ jobs:
           rockspec: ${{ matrix.package }}
 
 
-  examples:
+  web-server-examples:
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
@@ -65,3 +65,23 @@ jobs:
       - name: Stop ${{ matrix.name }} container
         run: |
           docker stop ${{ matrix.name }}
+
+  plain-lua-examples:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        name: [ "hello-debian"]
+    env:
+      LD_SDK_KEY: foo
+    steps:
+      - uses: actions/checkout@v4
+      - name: Build ${{ matrix.name }} image
+        run: |
+          docker build -t launchdarkly:${{ matrix.name }} -f ./examples/${{ matrix.name }}/Dockerfile .
+      - name: Run ${{ matrix.name }} container in foreground
+        run: |
+          docker run --env LD_SDK_KEY="$LD_SDK_KEY" launchdarkly:${{ matrix.name }} > logs.txt
+      - name: Verify output
+        run: |
+          grep -F "is false for this user" logs.txt || (echo "Expected false evaluation!" && exit 1)

examples/hello-debian/Dockerfile

@@ -0,0 +1,49 @@
+FROM debian:bookworm
+
+# {{ x-release-please-start-version }}
+ARG VERSION=2.1.0
+# {{ x-release-please-end }}
+
+# For unknown reasons, it appears that boost.json and boost.url aren't included in the
+# libboost-all package.
+
+RUN apt-get update && apt-get install -y \
+    git netbase curl libssl-dev libssl3 apt-transport-https ca-certificates \
+    software-properties-common \
+    cmake ninja-build build-essential \
+    libboost1.81-all-dev libboost-json1.81-dev libboost-url1.81-dev \
+    luarocks
+
+
+RUN mkdir cpp-sdk-libs
+RUN git clone --branch launchdarkly-cpp-server-v3.3.3 https://github.com/launchdarkly/cpp-sdks.git && \
+    cd cpp-sdks && \
+    mkdir build-dynamic && \
+    cd build-dynamic && \
+    cmake -GNinja \
+        -DLD_BUILD_EXAMPLES=OFF \
+        -DBUILD_TESTING=OFF \
+        -DLD_BUILD_SHARED_LIBS=ON \
+        -DLD_DYNAMIC_LINK_OPENSSL=ON .. && \
+    cmake --build . --target launchdarkly-cpp-server && \
+    cmake --install . --prefix=../../cpp-sdk-libs
+
+
+
+RUN mkdir hello-debian
+
+# The source .c file and the rockspec are needed to compile the LuaRock.
+COPY launchdarkly-server-sdk-${VERSION}-0.rockspec .
+COPY launchdarkly-server-sdk.c .
+
+# The example expects to find the env-helper script up one directory, so preserve that structure
+# when copying. The purpose of env-helper is to allow the flag key & SDK keys to be injected via
+# environment variable (LD_SDK_KEY and LD_FLAG_KEY).
+COPY ./examples/hello-debian/hello.lua hello-debian/
+COPY ./examples/env-helper env-helper
+
+
+RUN luarocks make launchdarkly-server-sdk-${VERSION}-0.rockspec LD_DIR=./cpp-sdk-libs
+
+ENV LD_LIBRARY_PATH=../cpp-sdk-libs/lib
+ENTRYPOINT ["lua", "hello-debian/hello.lua"]

examples/hello-debian/README.md

@@ -0,0 +1,17 @@
+# LaunchDarkly Lua server-side SDK Debian Bookworm example
+
+We've built a minimal dockerized example of using the Lua SDK within a Debian Bookworm Docker container. 
+
+## Build instructions
+
+1. On the command line from the **root** of the repo, build the Docker image:
+`docker build -t hello-debian -f ./examples/hello-debian/Dockerfile .`.
+2. Run the demo with
+    ```bash
+    docker run --rm --name hello-debian --env LD_SDK_KEY="my-sdk-key" --env LD_FLAG_KEY="my-boolean-flag" hello-debian
+    ```
+3. **Note:** the SDK key and flag key are passed with environment variables into the container. The `LD_FLAG_KEY` should be a boolean-type flag in your environment. If you don't pass 
+`LD_FLAG_KEY`, then the default flag key `my-boolean-flag` will be used.
+
+You should receive the message:
+> Feature flag is <true/false> for this user context

examples/hello-debian/hello.lua

@@ -0,0 +1,25 @@
+local ld = require("launchdarkly_server_sdk")
+local get_from_env_or_default = dofile("../env-helper/get_from_env_or_default.lua")
+
+-- Set MY_SDK_KEY to your LaunchDarkly SDK key.
+local MY_SDK_KEY = ""
+
+-- Set MY_FLAG_KEY to the boolean-type feature flag key you want to evaluate.
+local MY_FLAG_KEY = "my-boolean-flag"
+
+
+local config = {}
+
+local sdk_key = get_from_env_or_default("LD_SDK_KEY", MY_SDK_KEY)
+local client = ld.clientInit(sdk_key, 1000, config)
+
+local user = ld.makeContext({
+    user = {
+        key = "example-user-key",
+        name = "Sandy"
+    }
+})
+
+local flag_key = get_from_env_or_default("LD_FLAG_KEY", MY_FLAG_KEY)
+local value = client:boolVariation(user, flag_key, false)
+print("Feature flag ".. flag_key .." is "..tostring(value).." for this user context")

scripts/get-cpp-sdk-locally.sh

@@ -6,7 +6,7 @@
 # Locally, it's more convenient to built the C++ SDK from source - to be able to switch branches,
 # change built options, etc.
 
-# Usage: ./scripts/build-cpp-server.sh <tag>
+# Usage: ./scripts/get-cpp-sdk-locally.sh <tag>
 # If no tag is supplied, it uses 'main'.
 #
 # The SDK headers/libs are installed in ./cpp-sdks/build/INSTALL.