Schema CLI

Saiku ships a small schema tool inside the launcher jar. It converts a Mondrian schema between XML and YAML, and lints one before you upload it. Three subcommands, no server needed, fast enough to put in a git hook.

Run it straight from the jar you already have:

java -cp saiku-<version>.jar mondrian.schema.yaml.SchemaCli <command>

That’s a mouthful to type more than once, so the examples below assume a shell alias:

alias mondrian-schema='java -cp /path/to/saiku-<version>.jar mondrian.schema.yaml.SchemaCli'

Tip

Running it with no arguments prints the usage summary — handy when you’ve forgotten whether it’s to-yaml or to_yaml.

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Commands

to-yaml — convert XML to YAML

mondrian-schema to-yaml <input.xml> [-o output.yaml]

Reads a Mondrian-4 XML schema and writes the equivalent YAML representation. If -o is omitted, the YAML is written to stdout.

Example — convert FoodMart:

mondrian-schema to-yaml demo/FoodMart.mondrian.xml -o demo/FoodMart.yaml

Example — preview without saving:

mondrian-schema to-yaml demo/FoodMart.mondrian.xml | head -40

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to-xml — convert YAML to XML

mondrian-schema to-xml <input.yaml> [-o output.xml]

Reads a Mondrian-4 YAML schema and writes the equivalent XML. If -o is omitted, the XML is written to stdout. This is the same conversion the Saiku engine runs automatically at runtime — running it manually is useful for inspecting the output before deploying or for migrating back to an XML-native toolchain.

Example — convert back to XML:

mondrian-schema to-xml demo/FoodMart.yaml -o FoodMart-generated.xml

Example — pipe to a diff to verify round-trip fidelity:

mondrian-schema to-xml demo/FoodMart.yaml | diff demo/FoodMart.mondrian.xml -

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lint — validate a schema file

mondrian-schema lint <input.{yaml,xml}>

Parses and validates a schema file — YAML or XML, it works out which from the content. A clean file prints ok: <filename> and exits 0; a broken one prints the parse error to stderr, with the line and column, and exits 2:

error: XML parse failed: Document parse failed: [Fatal Error] :1:29:
Open quote is expected for attribute "name" associated with an
element type "Cube".

Lint is a structural check — it confirms the file parses and the schema is well-formed. It can’t tell you whether a column exists in your warehouse; that’s found at first query. A schema that passes lint will load into Mondrian, which is the useful guarantee for a pre-commit hook.

Example — lint a YAML schema:

mondrian-schema lint demo/FoodMart.yaml

Example — lint an XML schema:

mondrian-schema lint demo/FoodMart.mondrian.xml

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Exit codes

Code	Meaning
0	Success — no errors
1	Bad arguments or missing input file
2	Parse or validation failure — diagnostic written to stderr

These codes are suitable for use in CI pipelines and pre-save hooks.

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Typical workflows

Migrate XML to YAML

1. Convert your existing XML schema to YAML:

   mondrian-schema to-yaml my-schema.xml -o my-schema.yaml

2. Lint the YAML to confirm it is valid:

   mondrian-schema lint my-schema.yaml

3. Review and annotate my-schema.yaml with comments, then upload it to Saiku via the Schemas page.

Validate before saving

1. Author or edit your YAML schema locally.

2. Run lint to catch errors before uploading:

   mondrian-schema lint my-schema.yaml

   A 0 exit code means the schema parsed cleanly. Any errors appear on stderr with a line reference.

3. If you need to supply XML to an external tool (e.g. a legacy reporting client), convert on demand:

   mondrian-schema to-xml my-schema.yaml -o my-schema.xml

CI pipeline

Add a lint step to your CI pipeline to catch schema errors before they reach production:

# In .github/workflows/ci.yml or equivalent
- name: Lint Mondrian schemas
  run: |
    for f in schemas/*.yaml; do
      java -cp saiku.jar mondrian.schema.yaml.SchemaCli lint "$f"
    done

The script exits with code 2 on any parse or validation failure, which will fail the CI job automatically.

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Prerequisites

Just Java on your $PATH, and the launcher jar. Both come with any Saiku install; there’s no repository to clone and nothing to build.

If you’re a Saiku Cloud customer without a local jar, you don’t need this tool at all — the Schemas page will hand you the same schema as XML, YAML or canvas JSON from the row menu, and validates on save.

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Related

• YAML schemas — the full YAML element reference.
• Schemas — upload and manage schemas in the Saiku dashboard.
• Schema designer — generate a schema from a natural-language description.