docker: tolerate read-only config during merge

README.md

@@ -349,23 +349,32 @@ You can now run pyMC Repeater from within a [Docker Container](https://www.docke
 
 Here is what you'll need to do in order to get the container running:
 
-1. Copy the `config.yaml.example` to `config.yaml`
+1. Create the bind mount directories and copy the example config into the
+   Docker config directory.
 
 ```bash
-cp ./config.yaml.example ./config.yaml
+mkdir -p ./config ./data
+cp ./config.yaml.example ./config/config.yaml
 ```
 
 2. Run the configuration script and follow the prompts.
 
 ```bash
-sudo bash ./setup-radio-config.sh
+sudo bash ./setup-radio-config.sh ./config
 ```
 
-3. Modify the `config.yaml` file with a unique web UI password. This allows you to bypass the `/setup` page when logging for the first time. You can find the value under `repeater.security.admin_password`. Change to _anything_ besides the default of `admin123`.
+3. Modify `./config/config.yaml` with a unique web UI password. This allows you to bypass the `/setup` page when logging for the first time. You can find the value under `repeater.security.admin_password`. Change to _anything_ besides the default of `admin123`.
 
 4. Configure the [docker compose](./docker-compose.yml) to your specific hardware and file paths. Be sure to comment-out or delete lines that aren't required for your hardware. Please note that your hardware devices might be at a different path than those listed in the docker compose file.
 
-5. If you are using SPI/GPIO hardware, make sure the `GPIO_GID` and `SPI_GID`
+5. Make the bind mount directories writable by the container user. The image
+   runs as UID/GID `15888` by default unless you override `PUID` and `PGID`.
+
+```bash
+sudo chown -R 15888:15888 ./config ./data
+```
+
+6. If you are using SPI/GPIO hardware, make sure the `GPIO_GID` and `SPI_GID`
    values match the numeric group IDs on your host. The compose file defaults
    to `GPIO_GID=986` and `SPI_GID=989`.
 
@@ -374,7 +383,7 @@ getent group gpio
 getent group spi
 ```
 
-6. Build and start the container.
+7. Build and start the container.
 
 ```bash
 docker compose up -d --force-recreate --build

docker-compose.yml

@@ -4,8 +4,8 @@ services:
       context: .
       dockerfile: dockerfile
       args:
-        PUID: ${PUID:-1000}
-        PGID: ${PGID:-1000}
+        PUID: ${PUID:-15888}
+        PGID: ${PGID:-15888}
         GPIO_GID: ${GPIO_GID:-986}
         SPI_GID: ${SPI_GID:-989}
     container_name: pymc-repeater

docker-entrypoint.sh

@@ -13,16 +13,38 @@ YQ_CMD="${YQ_CMD:-/usr/local/bin/yq}"
 
 mkdir -p "${CONFIG_DIR}"
 
+print_permission_help() {
+    echo "If you are bind-mounting ./config or ./data, ensure the host paths are writable by ${RUNTIME_USER} (${RUNTIME_UID}:${RUNTIME_GID})." >&2
+    echo "For the default image user, run: sudo chown -R ${RUNTIME_UID}:${RUNTIME_GID} ./config ./data" >&2
+}
+
 copy_or_die() {
     src="$1"
     dest="$2"
     if ! cp "${src}" "${dest}"; then
         echo "Failed to initialize ${dest} from ${src}." >&2
-        echo "If you are bind-mounting ./config.yaml, ensure the host path is writable by ${RUNTIME_USER} (${RUNTIME_UID}:${RUNTIME_GID})." >&2
+        print_permission_help
         exit 1
     fi
 }
 
+use_runtime_merged_config() {
+    src="$1"
+    runtime_dir="$(mktemp -d /tmp/pymc-repeater-config.XXXXXX)"
+    runtime_config="${runtime_dir}/config.yaml"
+
+    if ! cp "${src}" "${runtime_config}"; then
+        echo "Failed to prepare temporary merged config at ${runtime_config}; keeping the existing config." >&2
+        return 1
+    fi
+
+    CONFIG_PATH="${runtime_config}"
+    echo "Using merged config from ${CONFIG_PATH} for this container start only." >&2
+    echo "Fix the bind-mounted config ownership so future upgrades can persist merged config changes." >&2
+    print_permission_help
+    return 0
+}
+
 merge_config_from_example() {
     config_path="$1"
 
@@ -62,7 +84,10 @@ merge_config_from_example() {
     fi
 
     if ! cmp -s "${config_path}" "${merged_config}"; then
-        copy_or_die "${merged_config}" "${config_path}"
+        if ! cp "${merged_config}" "${config_path}"; then
+            echo "Failed to update ${config_path} from merged config; the bind-mounted config is not writable." >&2
+            use_runtime_merged_config "${merged_config}" || true
+        fi
     fi
 
     cleanup_merge
@@ -70,7 +95,11 @@ merge_config_from_example() {
 }
 
 if [ ! -f "${EXAMPLE_PATH}" ] && [ -f "${BUNDLED_EXAMPLE_PATH}" ]; then
-    copy_or_die "${BUNDLED_EXAMPLE_PATH}" "${EXAMPLE_PATH}"
+    if ! cp "${BUNDLED_EXAMPLE_PATH}" "${EXAMPLE_PATH}"; then
+        echo "Could not copy bundled example config to ${EXAMPLE_PATH}; using bundled example for config merge only." >&2
+        print_permission_help
+        EXAMPLE_PATH="${BUNDLED_EXAMPLE_PATH}"
+    fi
 fi
 
 if [ -d "${CONFIG_PATH}" ]; then