A tool for transpiling JSON Schema into schemas for Avro and BigQuery.
JSON Schema is primarily used to validate incoming data, but contains enough information to describe the structure of the data. The transpiler encodes the schema for use with data serialization and processing frameworks. The main use-case is to enable ingestion of JSON documents into BigQuery through an Avro intermediary.
This tool can handle many of the composite types seen in modern data processing tools that support a SQL interface such as lists, structures, key-value maps, and type-variants.
This tool is designed for generating new schemas from
mozilla-pipeline-schemas,
the canonical source of truth for JSON schemas in the Firefox Data Platform.
bash
cargo install jsonschema-transpiler
```bash A tool to transpile JSON Schema into schemas for data processing
USAGE: jsonschema-transpiler [FLAGS] [OPTIONS] [file]
FLAGS: -w, --allow-maps-without-value Produces maps without a value field for incompatible or under-specified value schema -n, --force-nullable Treats all columns as NULLABLE, ignoring the required section in the JSON Schema object -h, --help Prints help information -c, --normalize-case snake_case column-names for consistent behavior between SQL engines --tuple-struct Treats tuple validation as an anonymous struct -V, --version Prints version information
OPTIONS:
-r, --resolve
ARGS:
JSON Schemas can be read from stdin or from a file.
```bash
$ schema='{"type": "object", "properties": {"foo": {"type": "boolean"}}}'
$ echo $schema | jq { "type": "object", "properties": { "foo": { "type": "boolean" } } }
$ echo $schema | jsonschema-transpiler --type avro { "fields": [ { "name": "foo", "type": [ { "type": "null" }, { "type": "boolean" } ] } ], "name": "root", "type": "record" }
$ echo $schema | jsonschema-transpiler --type bigquery { "fields": [ { "mode": "NULLABLE", "name": "foo", "type": "BOOL" } ], "mode": "REQUIRED", "type": "RECORD" } ```
Contributions are welcome. The API may change significantly, but the
transformation between various source formats should remain consistent. To aid
in the development of the transpiler, tests cases are generated from a language
agnostic format under tests/resources.
json
{
"name": "test-suite",
"tests": [
{
"name": "test-case",
"description": [
"A short description of the test case."
],
"tests": {
"avro": {...},
"bigquery": {...},
"json": {...}
}
},
...
]
}
Schemas provide a type system for data-structures. Most schema languages support a similar set of primitives. There are atomic data types like booleans, integers, and floats. These atomic data types can form compound units of structure, such as objects, arrays, and maps. The absence of a value is usually denoted by a null type. There are type modifiers, like the union of two types.
The following schemas are currently supported:
In the future, it may be possible to support schemas from similar systems like Parquet and Spark, or into various interactive data languages (IDL) like Avro IDL.
The jsonschema-transpiler is distributed as a crate via Cargo. Follow this checklist for deploying to crates.io.
Cargo.toml, as per Semantic Versioning.cargo test and CI succeeds.cargo publish. It must be run with the --no-verify flag due to issue #59.