Check Docker versions to ensure internal resolving works in test envi…

…ronment.

Due to a change in Docker's DNS resolver (moby/moby#47589) in version 25.0.5 (https://docs.docker.com/engine/release-notes/25.0/#2505), traffic to the mock resolver used in integration/batch tests is no longer forwarded. This is fixed in moby/moby#47822 in version 26.0.3 (https://docs.docker.com/engine/release-notes/26.0/#2603).

- Temporary add upgrade commands to CI because 26.0.3 is not yet in the default CI image
- Add checks to warn about incompatible versions
- Add documentation to help developers get the right versions

.github/workflows/docker.yml

@@ -259,6 +259,12 @@ jobs:
       PY_COLORS: "1"
 
     steps:
+      - if: ${{ matrix.os }} == ubuntu-24.04
+        name: Upgrade to at least Docker 26.1.3 to fix DNS issues
+        run: |
+          sudo apt update
+          sudo apt install --upgrade docker-ce
+
       - name: Enable ip6tables in Docker
         run: |
           sudo bash -c 'echo "{ \"ip6tables\": true, \"experimental\":true}" > /etc/docker/daemon.json'
@@ -527,6 +533,12 @@ jobs:
       PY_COLORS: "1"
 
     steps:
+      - if: ${{ matrix.os }} == ubuntu-24.04
+        name: Upgrade to at least Docker 26.1.3 to fix DNS issues
+        run: |
+          sudo apt update
+          sudo apt install --upgrade docker-ce
+
       - name: Enable ip6tables in Docker
         run: |
           sudo bash -c 'echo "{ \"ip6tables\": true, \"experimental\":true}" > /etc/docker/daemon.json'

documentation/Docker-getting-started.md

@@ -9,6 +9,7 @@ An OCI compatible container runtime with [Compose V2](https://docs.docker.com/co
 - [Docker](https://docs.docker.com/get-docker/) for Linux, (supported, tested version 24.0.2)
 - [Docker](https://docs.docker.com/get-docker/) for Mac (supported, tested version 4.21.0)
 - [Colima](https://github.com/abiosoft/colima) for Mac (recommended, tested version 0.5.5)
+- [OrbStack](https://orbstack.dev/download) for Mac (non open source, free, tested version 1.6.1)
 - [Docker](https://docs.docker.com/get-docker/) for Windows (untested)
 
 **notice**: newer versions of Docker (25+) might experience issues with internal DNS resolver. This is possibly a bug in Docker Compose:

integration_tests/conftest.py

@@ -2,6 +2,7 @@
 import time
 import subprocess
 import os
+from packaging.version import Version
 
 # primary URL for internet.nl test website
 APP_DOMAIN = "internet.test"
@@ -199,7 +200,7 @@ def pytest_report_header(config):
 
     try:
         docker_compose_version = subprocess.check_output(
-            "    docker compose version --short", shell=True, universal_newlines=True
+            "docker compose version --short", shell=True, universal_newlines=True
         ).strip()
     except Exception:
         docker_compose_version = "n/a"
@@ -215,3 +216,21 @@ def print_red(*args):
     print("\033[91m", end=None)
     print(*args)
     print("\033[0m", end=None)
+
+
+@pytest.fixture(autouse=True)
+def check_docker_version():
+    """Some versions of Docker/Compose are incompatible because of the way their networking/DNS
+    works. Check this and instruct the user how to resolve the issues."""
+
+    docker_server_version = subprocess.check_output(
+        "docker version --format '{{.Server.Version}}'",
+        shell=True,
+        universal_newlines=True,
+    ).strip()
+
+    if Version("25.0.5") <= Version(docker_server_version) < Version("26.0.3"):
+        pytest.fail(
+            f"Docker Server version {docker_server_version} not compatible, refer to "
+            "`documentation/Docker-getting-started.md#Prerequisites` for more info."
+        )