Validation¶

Validation is how SimDB and a server decide whether a simulation is complete, intact, and acceptable. There are three independent layers. For the commands, see Validate a simulation; for the server settings, see Configure validation.

1. Integrity (checksums)¶

When a simulation is ingested, SimDB records a checksum for every input and output: a SHA-1 hash for ordinary files, and a content hash derived from the IMAS data for IMAS entries. During push and validation these checksums are recomputed and compared. A mismatch means the data changed since it was catalogued (or a file is missing), and the simulation will not validate.

This is the most common cause of validation failure: one of the data sources is absent, or something changed after ingestion.

2. Metadata schema¶

A server can require specific metadata through a validation-schema.yaml file, expressed as Cerberus rules. For example, a server might require a string description field. Different servers can have different rules, so a simulation that is valid for one server may not be valid for another.

Inspect a server’s schema with:

simdb remote SERVER schema

and check a local simulation against it before pushing with:

simdb simulation validate SERVER SIM_ID

Failing to provide a server’s mandatory metadata is the second common cause of validation failure.

3. File-content validation¶

Optionally, a server can inspect the contents of data files with a file validator. The validator currently available is the IDS validator (the imas-validator package), which applies rulesets to IMAS data, for example checking that mandatory IDS quantities are populated and values fall within expected ranges.

File validation is configured server-side under [file_validation] (see Server configuration) and runs when the server is set to validate uploads automatically.

When validation runs¶

• On the client, on demand, with simdb simulation validate. This runs integrity and metadata checks against the target server’s rules before you push, so you can fix problems early.

• On the server, when auto_validate is enabled, uploaded simulations are validated automatically (including any configured file validation). With error_on_fail enabled, simulations that fail are rejected.

The outcome is reflected in the simulation’s status.