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Variables & Secrets

Environment variables and secrets used to configure Sync-in.

🌱 Server environment variables​

During initialization​

  • SKIP_INIT: Skips the initialization step (database migration, administrator account creation, permission updates, etc.)
  • INIT_ADMIN: If set (to true or any other non-empty value), forces the creation of the administrator account during initialization.
  • INIT_ADMIN_LOGIN: Username of the administrator account to be created during initialization.
  • INIT_ADMIN_PASSWORD: Password of the administrator account to be created during initialization.
  • PUID: Defines the user identifier (UID) used by the container (useful for file permissions).
  • PGID: Defines the group identifier (GID) used by the container (useful for access to shared volumes).

During execution​

All Sync-in server configuration parameters can be defined via environment variables prefixed with SYNCIN_, see the corresponding section.

🔐 Secrets management​

Docker Secrets (especially in a Swarm or Compose environment) allow sensitive data (such as passwords, API keys…) to be securely stored by mounting them into containers as files, typically in the /run/secrets/<secret_name> directory.

By design, Docker never directly converts these secrets into environment variables, in order to limit the risk of leakage (for example via docker inspect or environment variables accessible within the process). The Sync-in Docker image, as well as many official images (MySQL, PostgreSQL ...), adopts and supports this *_FILE convention.

For example, instead of directly defining the SYNCIN_MYSQL_URL environment variable, it is recommended to use SYNCIN_MYSQL_URL_FILE=/run/secrets/mysql_password. The Sync-in server will then read the contents of the specified file to initialize the variable internally.

This approach ensures secure secrets management while maintaining compatibility with existing configuration mechanisms.

For more information, see the official Docker documentation regarding secrets management.