Skip to content

Environment Variables#

The Virtual Parameter Service supports configuration via environment variables, which are particularly useful when deploying with Docker or Docker Compose.

Supported Variables#

Variable Default Description
CONFIG_FILE_PATH Configs/AppConfig.json Path to the AppConfig.json configuration file.
LOG_FILE_PATH %ProgramData%\Mclaren_Applied_Ltd\VirtualParameterService\Logs\vps-svc-log.txt Path to the log file. Must be a full file path ending in .txt.
METRIC_PORT 10010 The port on which the Prometheus metrics HTTP endpoint is exposed.

LOG_FILE_PATH must include a filename ending in .txt

If the path doesn't end in .txt, the service does not treat it as a target directory and append vps-svc-log.txt inside it. Instead:

  • A path with no .txt extension but with a parent directory (e.g. /logs/output or /logs) has its last segment dropped, and vps-svc-log.txt is written into what's left of the path (e.g. /logs/output → /logs/vps-svc-log.txt; /logs → the filesystem root).
  • A path with no .txt extension and no parent directory at all (a bare name like logs, relative to the working directory) is treated as a subfolder, with vps-svc-log.txt appended inside it.
  • A path with some other extension (e.g. .log) is rejected outright — the service logs a console warning and reverts to the default path.

Always set LOG_FILE_PATH to a full path that ends in a .txt filename, e.g. /logs/vps-svc-log.txt.

Precedence Order#

  • CONFIG_FILE_PATH / LOG_FILE_PATH: the -c / -l command-line arguments set these environment variables for the process before they're read, so a command-line argument always wins over a manually-set environment variable, which in turn wins over the built-in default. If a Serilog section is present in AppConfig.json, it takes over logging configuration entirely and LOG_FILE_PATH (env var or -l) is ignored — see Logging.
  • METRIC_PORT: unlike the two settings above, this also has an AppConfig.json equivalent — VirtualParameterServiceConfig.MetricPort (see AppConfig Reference). If METRIC_PORT is set, it overrides the MetricPort value from AppConfig.json.

Usage with Docker Compose#

virtual-parameter-service:
  image: atlasplatformdocker/virtual-parameter-service-host:latest
  ports:
    - "10010:10010"
  volumes:
    - ./virtual-parameter-service/AppConfig.json:/config/AppConfig.json
  environment:
    - CONFIG_FILE_PATH=/config/AppConfig.json
    - LOG_FILE_PATH=/logs/vps-svc-log.txt
    - METRIC_PORT=10010

Usage with Docker Run#

docker run -d \
  --name virtual-parameter-service \
  -p 10010:10010 \
  -e CONFIG_FILE_PATH=/config/AppConfig.json \
  -e LOG_FILE_PATH=/logs/vps-svc-log.txt \
  -e METRIC_PORT=10010 \
  -v C:\path\to\AppConfig.json:/config/AppConfig.json \
  atlasplatformdocker/virtual-parameter-service-host:latest

Environment variables vs command arguments

When using Docker Compose, environment variables are generally preferred over command arguments (-c, -l) because only one command directive can be specified in the compose file.