testcontainers#7239 - reduce the pain by making it configurable

core/src/main/java/org/testcontainers/containers/ContainerisedDockerCompose.java

@@ -11,6 +11,7 @@
 import org.testcontainers.utility.DockerImageName;
 import org.testcontainers.utility.MountableFile;
 import org.testcontainers.utility.PathUtils;
+import org.testcontainers.utility.TestcontainersConfiguration;
 
 import java.io.File;
 import java.util.List;
@@ -43,7 +44,10 @@ public ContainerisedDockerCompose(DockerImageName dockerImageName, List<File> co
         final String composeFileEnvVariableValue = Joiner.on(UNIX_PATH_SEPARATOR).join(absoluteDockerComposeFiles); // we always need the UNIX path separator
         logger().debug("Set env COMPOSE_FILE={}", composeFileEnvVariableValue);
         addEnv(ENV_COMPOSE_FILE, composeFileEnvVariableValue);
-        withCopyFileToContainer(MountableFile.forHostPath(pwd), containerPwd);
+        if (TestcontainersConfiguration.getInstance().isComposeFsModeMount())
+            addFileSystemBind(pwd, containerPwd, BindMode.READ_WRITE);
+        else
+            withCopyFileToContainer(MountableFile.forHostPath(pwd), containerPwd);
 
         // Ensure that compose can access docker. Since the container is assumed to be running on the same machine
         //  as the docker daemon, just mapping the docker control socket is OK.

core/src/main/java/org/testcontainers/utility/TestcontainersConfiguration.java

@@ -23,6 +23,7 @@
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.Properties;
 import java.util.concurrent.atomic.AtomicReference;
@@ -221,6 +222,10 @@ public Integer getClientPingTimeout() {
         return Integer.parseInt(getEnvVarOrProperty("client.ping.timeout", "10"));
     }
 
+    public boolean isComposeFsModeMount() {
+        return "mount".equalsIgnoreCase(getEnvVarOrProperty("compose.container.fs.mode", "copy"));
+    }
+
     @Nullable
     @Contract("_, !null, _ -> !null")
     private String getConfigurable(

docs/features/advanced_options.md

@@ -83,3 +83,21 @@ The previous implementation should be registered in `META-INF/services/org.testc
 Usually, containers are started sequentially when more than one container is used.
 Using `Startables.deepStart(container1, container2, ...).join()` will start all containers in parallel. 
 This can be advantageous to reduce the impact of the container startup overhead.
+
+## Containerized Docker Compose
+
+If you are using `ComposeContainer` (for `compose`, v2) or `DockerComposeContainer`
+(`docker-compose`, v1), then you may be running the `compose` plugin/program
+inside a docker container itself.
+This works by running the `compose` commands inside a container,
+to communicate with a docker engine running somewhere else.
+
+If you need to access files on your local filesystem,
+such as with a `compose` file with a build context instead of an image,
+then you may find that it is beneficial to opt out of the default
+Testcontainers behavior of copying files to containers, and use a fs mount:
+
+```properties
+compose.container.fs.mode=bind
+#compose.container.fs.mode=copy
+```