use per user docker socket if system docker socket doesn't exist (#361)

* use per user docker socket if system docker socket doesn't exist

* add retry

arch/tools/cli/core.py

@@ -4,7 +4,8 @@ import time
 import sys
 import glob
 import docker
-from cli.utils import getLogger
+from docker.errors import DockerException
+from cli.utils import getLogger, update_docker_host_env
 from cli.consts import (
     ARCHGW_DOCKER_IMAGE,
     ARCHGW_DOCKER_NAME,
@@ -110,7 +111,12 @@ def start_arch(arch_config_file, env, log_timeout=120, foreground=False):
     log.info("Starting arch gateway")
 
     try:
-        client = docker.from_env()
+        try:
+            client = docker.from_env()
+        except DockerException as e:
+            # try setting up the docker host environment variable and retry
+            update_docker_host_env()
+            client = docker.from_env()
 
         try:
             container = client.containers.get("archgw")

arch/tools/cli/utils.py

@@ -1,6 +1,8 @@
+import os
 import yaml
 import logging
 import docker
+from docker.errors import DockerException
 
 from cli.consts import ARCHGW_DOCKER_IMAGE, ARCHGW_DOCKER_NAME
 
@@ -19,10 +21,32 @@ def getLogger(name="cli"):
 log = getLogger(__name__)
 
 
+def update_docker_host_env():
+    """
+    Update DOCKER_HOST environment variable to use the local Docker socket
+    """
+    if os.getenv("DOCKER_HOST"):
+        return
+
+    default_docker_socket = os.getenv("DEFAULT_DOCKER_SOCKET", "/var/run/docker.sock")
+    if not os.path.exists(default_docker_socket):
+        home_dir = os.getenv("HOME")
+        docker_host = f"unix://{home_dir}/.docker/run/docker.sock"
+        log.info(
+            f"Default docker socket {default_docker_socket} not found, using {docker_host}"
+        )
+        os.environ["DOCKER_HOST"] = docker_host
+
+
 def validate_schema(arch_config_file: str) -> None:
     try:
-        client = docker.from_env()
+        try:
-        # Run the container with detach=True to avoid blocking main process
+            client = docker.from_env()
+        except DockerException as e:
+            # try setting up the docker host environment variable and retry
+            update_docker_host_env()
+            client = docker.from_env()
+
         container = client.containers.run(
             image=ARCHGW_DOCKER_IMAGE,
             volumes={