Support for Docker environment files

core/src/main/java/org/lflang/generator/docker/DockerComposeGenerator.java

@@ -3,9 +3,11 @@
 import java.io.BufferedWriter;
 import java.io.FileWriter;
 import java.io.IOException;
+import java.nio.file.Path;
 import java.util.List;
 import java.util.Objects;
 import java.util.stream.Collectors;
+import org.apache.commons.text.StringEscapeUtils;
 import org.lflang.generator.LFGeneratorContext;
 import org.lflang.target.property.DockerProperty;
 import org.lflang.util.FileUtil;
@@ -65,9 +67,22 @@ protected String getServiceDescription(DockerData data) {
                    extra_hosts:
                      - "host.docker.internal:host-gateway"
                    environment:
-                     LF_TELEGRAF_HOST_NAME: ${LF_TELEGRAF_HOST_NAME:-host.docker.internal}
+                     - "LF_TELEGRAF_HOST_NAME=${LF_TELEGRAF_HOST_NAME:-host.docker.internal}"
+                   %s
            """
-        .formatted(getServiceName(data), getBuildContext(data), getContainerName(data));
+        .formatted(
+            getServiceName(data),
+            getBuildContext(data),
+            getContainerName(data),
+            getEnvironmentFile());
+  }
+
+  private String getEnvironmentFile() {
+    var file = context.getTargetConfig().get(DockerProperty.INSTANCE).envFile();
+    if (!file.isEmpty()) {
+      return "env_file: \"%s\"".formatted(StringEscapeUtils.escapeXSI(file));
+    }
+    return "";
   }
 
   /** Return the name of the service represented by the given data. */
@@ -102,11 +117,23 @@ public void writeDockerComposeFile(List<DockerData> services) throws IOException
    */
   public void writeDockerComposeFile(List<DockerData> services, String networkName)
       throws IOException {
+    var dockerComposeDir = context.getFileConfig().getSrcGenPath();
     var contents =
         String.join(
             "\n", this.generateDockerServices(services), this.generateDockerNetwork(networkName));
-    FileUtil.writeToFile(
-        contents, context.getFileConfig().getSrcGenPath().resolve("docker-compose.yml"));
+    FileUtil.writeToFile(contents, dockerComposeDir.resolve("docker-compose.yml"));
+    var envFile = context.getTargetConfig().get(DockerProperty.INSTANCE).envFile();
+    if (!envFile.isEmpty()) {
+      var found = FileUtil.findInPackage(Path.of(envFile), context.getFileConfig());
+      if (found != null) {
+        var destination = dockerComposeDir.resolve(found.getFileName());
+        FileUtil.copyFile(found, destination);
+        this.context
+            .getErrorReporter()
+            .nowhere()
+            .info("Environment file written to " + destination);
+      }
+    }
   }
 
   /**

core/src/main/java/org/lflang/target/property/DockerProperty.java

@@ -42,6 +42,7 @@ public DockerOptions fromAst(Element node, MessageReporter reporter) {
     var preBuildScript = "";
     var postBuildScript = "";
     var runScript = "";
+    var envFile = "";
 
     if (node.getLiteral() != null) {
       if (ASTUtils.toBoolean(node)) {
@@ -61,6 +62,7 @@ public DockerOptions fromAst(Element node, MessageReporter reporter) {
           case POST_BUILD_SCRIPT ->
               postBuildScript = ASTUtils.elementToSingleString(entry.getValue());
           case RTI_IMAGE -> rti = ASTUtils.elementToSingleString(entry.getValue());
+          case ENV_FILE -> envFile = ASTUtils.elementToSingleString(entry.getValue());
         }
       }
     }
@@ -73,7 +75,8 @@ public DockerOptions fromAst(Element node, MessageReporter reporter) {
         shell,
         preBuildScript,
         postBuildScript,
-        runScript);
+        runScript,
+        envFile);
   }
 
   @Override
@@ -109,6 +112,7 @@ public Element toAstElement(DockerOptions value) {
           case PRE_RUN_SCRIPT -> pair.setValue(ASTUtils.toElement(value.preRunScript));
           case POST_BUILD_SCRIPT -> pair.setValue(ASTUtils.toElement(value.postBuildScript));
           case RTI_IMAGE -> pair.setValue(ASTUtils.toElement(value.rti));
+          case ENV_FILE -> pair.setValue(ASTUtils.toElement(value.envFile));
         }
         kvp.getPairs().add(pair);
       }
@@ -135,7 +139,8 @@ public record DockerOptions(
       String shell,
       String preBuildScript,
       String postBuildScript,
-      String preRunScript) {
+      String preRunScript,
+      String envFile) {
 
     /** Default location to pull the rti from. */
     public static final String DOCKERHUB_RTI_IMAGE = "lflang/rti:rti";
@@ -146,7 +151,7 @@ public record DockerOptions(
     public static final String LOCAL_RTI_IMAGE = "rti:local";
 
     public DockerOptions(boolean enabled) {
-      this(enabled, false, "", "", DOCKERHUB_RTI_IMAGE, DEFAULT_SHELL, "", "", "");
+      this(enabled, false, "", "", DOCKERHUB_RTI_IMAGE, DEFAULT_SHELL, "", "", "", "");
     }
   }
 
@@ -158,6 +163,7 @@ public DockerOptions(boolean enabled) {
   public enum DockerOption implements DictionaryElement {
     NO_BUILD("no-build", PrimitiveType.BOOLEAN),
     BUILDER_BASE("builder-base", PrimitiveType.STRING),
+    ENV_FILE("env-file", PrimitiveType.STRING),
     RUNNER_BASE("runner-base", PrimitiveType.STRING),
     RTI_IMAGE("rti-image", PrimitiveType.STRING),
     PRE_BUILD_SCRIPT("pre-build-script", PrimitiveType.STRING),

test/C/src/docker/federated/.env

@@ -0,0 +1,2 @@
+# define COMPOSE_DEBUG based on DEV_MODE, defaults to false
+COMPOSE_DEBUG=${DEV_MODE:-false}

test/C/src/docker/federated/DockerOptions.lf

@@ -7,7 +7,8 @@ target C {
     pre-build-script: "foo.sh",
     pre-run-script: "bar.sh",
     post-build-script: "baz.sh",
-    no-build: false
+    no-build: false,
+    env-file: ".env"
   },
   cmake-include: "cmake-check-environment-variable.cmake"
 }