Hello! I see you are talking about JSONSchema, not just JSON itself.
We're trying to do a similar thing at Wikimedia and have developed some tooling around this. JsonSchemaFlinkConverter <https://gerrit.wikimedia.org/r/plugins/gitiles/wikimedia-event-utilities/+/refs/heads/master/eventutilities-flink/src/main/java/org/wikimedia/eventutilities/flink/formats/json/JsonSchemaFlinkConverter.java> has some logic to convert from JSONSchema Jackson ObjectNodes to Flink Table DataType or Table SchemaBuilder, or Flink DataStream TypeInformation[Row]. Some of the conversions from JSONSchema to Flink type are opinionated. You can see the mappings here <https://gerrit.wikimedia.org/r/plugins/gitiles/wikimedia-event-utilities/+/refs/heads/master/eventutilities-flink/src/main/java/org/wikimedia/eventutilities/flink/formats/json/DataTypeSchemaConversions.java> . On Wed, Nov 9, 2022 at 2:33 AM Theodor Wübker <theo.wueb...@inside-m2m.de> wrote: > Thanks for your reply Yaroslav! The way I do it with Avro seems similar to > what you pointed out: > > ResolvedSchema resultSchema = resultTable.getResolvedSchema(); > DataType type = resultSchema.toSinkRowDataType(); > org.apache.avro.Schema converted = > AvroSchemaConverter.convertToSchema(type.getLogicalType()); > > I mentioned the ResolvedSchema because it is my starting point after the > SQL operation. It seemed to me that I can not retrieve something that > contains more schema information from the table so I got myself this. About > your other answers: It seems the classes you mentioned can be used to > serialize actual Data? However this is not quite what I want to do. > Essentially I want to convert the schema of a Flink table to both Protobuf > *schema* and JSON *schema* (for Avro as you can see I have it already). > It seems odd that this is not easily possible, because converting from a > JSON schema to a Schema of Flink is possible using the > JsonRowSchemaConverter. However the other way is not implemented it seems. > This is how I got a Table Schema (that I can use in a table descriptor) > from a JSON schema: > > TypeInformation<Row> type = JsonRowSchemaConverter.convert(json); > DataType row = TableSchema.fromTypeInfo(type).toPhysicalRowDataType(); > Schema schema = Schema.newBuilder().fromRowDataType(row).build(); > > Sidenote: I use deprecated methods here, so if there is a better approach > please let me know! But it shows that in Flink its easily possible to > create a Schema for a TableDescriptor from a JSON Schema - the other way is > just not so trivial it seems. And for Protobuf so far I don’t have any > solutions, not even creating a Flink Schema from a Protobuf Schema - not to > mention the other way around. > > -Theo > > (resent because I accidentally only responded to you, not the Mailing list > - sorry) > >
