plumb through exec instead of assuming /bin/sh (#290)

instead of assuming `CMD` is a shell script, just use `exec`.

this means we can support any valid `CMD`, with the downside that shell
scripts will now need to set their own setopts. we trade some
transparency for more compatibility and control.

this also cleans up the scripts logging a bit, and adds a `socat`
registry proxy to support local registries for the dind driver. the
`socat` works almost identically to how containerd mirroring is done
with the k3sindocker driver.

cmd/entrypoint/kodata/entrypoint-wrapper.sh

@@ -1,42 +1,63 @@
 #!/bin/sh
 set -eu
 
+info() {
+  printf '%s [INFO] %s\n' "$(date "+%Y-%m-%dT%H:%M:%S")" "$1" >&2
+}
+
+warn() {
+  printf '%s [WARN] %s\n' "$(date "+%Y-%m-%dT%H:%M:%S")" "$1" >&2
+}
+
+error() {
+  printf '%s [ERROR] %s\n' "$(date "+%Y-%m-%dT%H:%M:%S")" "$1" >&2
+}
+
 # Print usage and exit with error
 usage() {
-  echo "Usage: $0 <test-script-path>"
-  echo "Environment variables:"
-  echo "  IMAGETEST_DRIVER: Type of test environment (docker_in_docker, k3s_in_docker)"
+  error "Usage: $0 <test-script-path>"
+  error "Environment variables:"
+  error "  IMAGETEST_DRIVER: Type of test environment (docker_in_docker, k3s_in_docker)"
   exit 1
 }
 
 # Validate that a test script exists and is executable.
 # This function is used by all drivers to ensure consistent validation.
 # Arguments:
 #   $1: Path to the test script
-validate_test_script() {
-  script_path="$1"
+validate_cmd() {
+  cmdarg="$1"
 
-  if [ ! -f "$script_path" ]; then
-    echo "Error: Test script '$script_path' does not exist"
-    exit 1
+  # Only try to do validations if cmdarg is a file (presumably a script of sorts)
+  if [ -f "$cmdarg" ]; then
+    if [ ! -x "$cmdarg" ]; then
+      chmod +x "$cmdarg" || warn "Failed to make script executable"
+    fi
   fi
+}
+
+init_registry_proxy() {
+  case "${IMAGETEST_REGISTRY}" in
+  "localhost:"*)
+    info "Attempting to start registry proxy"
 
-  if [ ! -x "$script_path" ]; then
-    echo "Warning: Test script '$script_path' is not executable, attempting to set execute permission"
-    if ! chmod +x "$script_path"; then
-      echo "Error: Failed to make test script executable"
-      exit 1
+    port=$(echo "$IMAGETEST_REGISTRY" | sed -n 's/^localhost:\([0-9]\+\).*/\1/p')
+    if [ -n "${port}" ]; then
+      info "Detected localhost and port ${port}, starting registry proxy"
+
+      # Start a non-forked socat process to proxy localhost to dockers magic dns
+      setsid socat -d -lf /tmp/local-registry-proxy.log TCP-LISTEN:"${port}",fork,reuseaddr TCP:host.docker.internal:"${port}" </dev/null >/dev/null 2>&1 &
     fi
-    echo "Successfully made test script executable"
-  fi
+    ;;
+  esac
 }
 
 # Initialize and manage a Docker-in-Docker environment.
 # This function handles the Docker daemon startup and monitoring.
 # Arguments:
 #   $1: Path to the test script (already validated)
 init_docker_in_docker() {
-  test_script="$1"
+  cmd="$1"
   timeout=30
   log_dir="/var/log/docker"
 
@@ -47,74 +68,75 @@ init_docker_in_docker() {
   /usr/bin/dockerd-entrypoint.sh dockerd >"$log_dir/dockerd.log" 2>&1 &
 
   # Wait for Docker to be ready
-  echo "Waiting for Docker daemon to be ready..."
+  info "Waiting for Docker daemon to be ready..."
   while [ "$timeout" -gt 0 ]; do
     if docker version >/dev/null 2>&1; then
-      echo "Docker daemon is ready"
+      info "Docker daemon is ready"
       break
     fi
     timeout=$((timeout - 1))
-    echo "Waiting... ($timeout seconds remaining)"
+    info "Waiting... ($timeout seconds remaining)"
     sleep 1
   done
 
   if [ "$timeout" -le 0 ]; then
-    echo "Error: Docker daemon failed to start"
+    error "Docker daemon failed to start"
     exit 1
   fi
 
-  # Execute test script with strict shell options
-  exec /bin/sh -euxc ". $test_script"
+  # Maybe start a registry proxy
+  init_registry_proxy
+
+  exec "$cmd"
 }
 
 # Initialize and manage a K3s-in-Docker environment.
 # Arguments:
 #   $1: Path to the test script (already validated)
 init_k3s_in_docker() {
-  test_script="$1"
+  cmd="$1"
 
   # Ensure required environment variables are set
   if [ -z "${POD_NAME-}" ] || [ -z "${POD_NAMESPACE-}" ]; then
-    echo "Error: POD_NAME and POD_NAMESPACE environment variables must be set"
+    error "POD_NAME and POD_NAMESPACE environment variables must be set"
     exit 1
   fi
 
-  echo "Waiting for pod ${POD_NAME} to be ready..."
-  if ! kubectl wait --for=condition=Ready=true pod/${POD_NAME} -n "${POD_NAMESPACE}" --timeout=60s; then
-    echo "Error: Pod ${POD_NAME} failed to become ready"
+  info "Waiting for pod ${POD_NAME} to be ready..."
+  if ! kubectl wait --for=condition=Ready=true pod/"${POD_NAME}" -n "${POD_NAMESPACE}" --timeout=60s; then
+    error "Pod ${POD_NAME} failed to become ready"
     exit 1
   fi
 
-  # Execute test script with strict shell options
-  exec /bin/sh -euxc ". $test_script"
+  exec "$cmd"
 }
 
 # Validate command-line arguments
 if [ $# -ne 1 ]; then
   usage
 fi
 
-test_script="$1"
+cmd="$1"
 
 # Make sure IMAGETEST_DRIVER is set
 if [ -z "${IMAGETEST_DRIVER-}" ]; then
-  echo "Error: IMAGETEST_DRIVER environment variable not set"
+  error "IMAGETEST_DRIVER environment variable not set"
   usage
 fi
 
 # Validate the test script first, regardless of driver
-validate_test_script "$test_script"
+validate_cmd "$cmd"
 
 # Initialize the appropriate driver
 case "$IMAGETEST_DRIVER" in
 docker_in_docker)
-  init_docker_in_docker "$test_script"
+  init_docker_in_docker "$cmd"
   ;;
 k3s_in_docker)
-  init_k3s_in_docker "$test_script"
+  init_k3s_in_docker "$cmd"
   ;;
 *)
-  echo "Error: Unknown driver '$IMAGETEST_DRIVER'"
+  error "Unknown driver '$IMAGETEST_DRIVER'"
   usage
   ;;
 esac

internal/provider/tests_resource.go

@@ -337,6 +337,8 @@ func (t *TestsResource) do(ctx context.Context, data *TestsResourceModel) (ds di
 					}
 					envs["IMAGES"] = string(imgsResolvedData)
 					envs["IMAGETEST_DRIVER"] = string(data.Driver)
+					envs["IMAGETEST_REGISTRY"] = t.repo.RegistryStr()
+					envs["IMAGETEST_REPO"] = t.repo.String()
 
 					if os.Getenv("IMAGETEST_SKIP_TEARDOWN_ON_FAILURE") != "" || os.Getenv("IMAGETEST_SKIP_TEARDOWN") != "" {
 						envs["IMAGETEST_PAUSE_ON_ERROR"] = "true"