[docker] Containers may not always be present

java/server/src/org/openqa/selenium/docker/Docker.java

@@ -62,14 +62,18 @@ public Container create(ContainerConfig config) {
       .orElseThrow(() -> new DockerException("Unable to create container: " + config));
   }
 
-  public ContainerInfo inspect(ContainerId id) {
+  public Optional<ContainerInfo> inspect(ContainerId id) {
     Require.nonNull("Container id", id);
 
     LOG.info("Inspecting container with id: " + id);
 
-    return getDocker()
+    if (!getDocker().map(protocol -> protocol.isContainerPresent(id)).orElse(false)) {
+      return Optional.empty();
+    }
+
+    return Optional.of(getDocker()
       .map(protocol -> protocol.inspectContainer(id))
-      .orElseThrow(() -> new DockerException("Unable to inspect container: " + id));
+      .orElseThrow(() -> new DockerException("Unable to inspect container: " + id)));
   }
 
   private Optional<DockerProtocol> getDocker() {

java/server/src/org/openqa/selenium/docker/DockerProtocol.java

@@ -26,6 +26,7 @@ public interface DockerProtocol {
 
   Container create(ContainerConfig info);
   void startContainer(ContainerId id) throws DockerException;
+  boolean isContainerPresent(ContainerId id) throws DockerException;
   void stopContainer(ContainerId id, Duration timeout) throws DockerException;
   ContainerInfo inspectContainer(ContainerId id) throws DockerException;
   ContainerLogs getContainerLogs(ContainerId id) throws DockerException;

java/server/src/org/openqa/selenium/docker/v1_40/IsContainerPresent.java

@@ -0,0 +1,45 @@
+// Licensed to the Software Freedom Conservancy (SFC) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The SFC licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package org.openqa.selenium.docker.v1_40;
+
+import org.openqa.selenium.docker.ContainerId;
+import org.openqa.selenium.internal.Require;
+import org.openqa.selenium.remote.http.HttpHandler;
+import org.openqa.selenium.remote.http.HttpRequest;
+import org.openqa.selenium.remote.http.HttpResponse;
+
+import static org.openqa.selenium.remote.http.HttpMethod.GET;
+
+class IsContainerPresent {
+  private final HttpHandler client;
+
+  public IsContainerPresent(HttpHandler client) {
+    this.client = Require.nonNull("Http client", client);
+  }
+
+  public boolean apply(ContainerId id) {
+    Require.nonNull("Container id", id);
+
+    HttpResponse res = client.execute(
+      new HttpRequest(GET, String.format("/v1.40/containers/%s/json", id))
+        .addHeader("Content-Length", "0")
+        .addHeader("Content-Type", "text/plain"));
+
+    return res.isSuccessful();
+  }
+}

java/server/src/org/openqa/selenium/docker/v1_40/V140Docker.java

@@ -41,6 +41,7 @@ public class V140Docker implements DockerProtocol {
   private final CreateContainer createContainer;
   private final StartContainer startContainer;
   private final StopContainer stopContainer;
+  private final IsContainerPresent isContainerPresent;
   private final InspectContainer inspectContainer;
   private final GetContainerLogs containerLogs;
 
@@ -52,6 +53,7 @@ public V140Docker(HttpHandler client) {
     createContainer = new CreateContainer(this, client);
     startContainer = new StartContainer(client);
     stopContainer = new StopContainer(client);
+    isContainerPresent = new IsContainerPresent(client);
     inspectContainer = new InspectContainer(client);
     containerLogs = new GetContainerLogs(client);
   }
@@ -94,6 +96,15 @@ public Container create(ContainerConfig config) {
     return createContainer.apply(config);
   }
 
+  @Override
+  public boolean isContainerPresent(ContainerId id) throws DockerException {
+    Require.nonNull("Container id", id);
+
+    LOG.info("Checking if container is present: " + id);
+
+    return isContainerPresent.apply(id);
+  }
+
   @Override
   public void startContainer(ContainerId id) throws DockerException {
     Require.nonNull("Container id", id);

java/server/src/org/openqa/selenium/grid/docker/DockerOptions.java

@@ -32,6 +32,7 @@
 import org.openqa.selenium.grid.node.SessionFactory;
 import org.openqa.selenium.internal.Require;
 import org.openqa.selenium.json.Json;
+import org.openqa.selenium.net.HostIdentifier;
 import org.openqa.selenium.remote.http.ClientConfig;
 import org.openqa.selenium.remote.http.HttpClient;
 import org.openqa.selenium.remote.tracing.Tracer;
@@ -179,18 +180,25 @@ private DockerAssetsPath getAssetsPath(Docker docker) {
     // Selenium Server is running inside a Docker container, we will inspect that container
     // to get the mounted volume and use that. If no volume was mounted, no assets will be saved.
     // Since Docker 1.12, the env var HOSTNAME has the container id (unless the user overwrites it)
-    String hostname = System.getenv("HOSTNAME");
-    ContainerInfo info = docker.inspect(new ContainerId(hostname));
-    Optional<Map<String, Object>> mountedVolume = info.getMountedVolumes()
+    String hostname = HostIdentifier.getHostName();
+
+    Optional<ContainerInfo> info = docker.inspect(new ContainerId(hostname));
+    if (!info.isPresent()) {
+      return null;
+    }
+
+    Optional<Map<String, Object>> mountedVolume = info.get().getMountedVolumes()
       .stream()
       .filter(
         mounted ->
           CONTAINER_ASSETS_PATH.equalsIgnoreCase(String.valueOf(mounted.get("Destination"))))
       .findFirst();
+
     if (mountedVolume.isPresent()) {
       String hostPath = String.valueOf(mountedVolume.get().get("Source"));
       return new DockerAssetsPath(hostPath, CONTAINER_ASSETS_PATH);
     }
+
     return null;
   }