Apache Druid can ingest denormalized data in JSON, CSV, or a delimited form such as TSV, or any custom format. While most examples in the documentation use data in JSON format, it is not difficult to configure Druid to ingest any other delimited data.
Druid supports custom data formats and can use the `Regex` parser or the `JavaScript` parsers to parse these formats. Please note that using any of these parsers for
All forms of Druid ingestion require some form of schema object. The format of the data to be ingested is specified using the `inputFormat` entry in your [`ioConfig`](ingestion-spec.md#ioconfig).
| flattenSpec | JSON Object | Specifies flattening configuration for nested JSON data. See [`flattenSpec`](#flattenspec) for more info. | no |
| featureSpec | JSON Object | [JSON parser features](https://github.com/FasterXML/jackson-core/wiki/JsonParser-Features) supported by Jackson library. Those features will be applied when parsing the input JSON data. | no |
| columns | JSON array | Specifies the columns of the data. The columns should be in the same order with the columns of your data. | yes if `findColumnsFromHeader` is false or missing |
| findColumnsFromHeader | Boolean | If this is set, the task will find the column names from the header row. Note that `skipHeaderRows` will be applied before finding column names from the header. For example, if you set `skipHeaderRows` to 2 and `findColumnsFromHeader` to true, the task will skip the first two lines and then extract column information from the third line. `columns` will be ignored if this is set to true. | no (default = false if `columns` is set; otherwise null) |
| skipHeaderRows | Integer | If this is set, the task will skip the first `skipHeaderRows` rows. | no (default = 0) |
| columns | JSON array | Specifies the columns of the data. The columns should be in the same order with the columns of your data. | yes if `findColumnsFromHeader` is false or missing |
| findColumnsFromHeader | Boolean | If this is set, the task will find the column names from the header row. Note that `skipHeaderRows` will be applied before finding column names from the header. For example, if you set `skipHeaderRows` to 2 and `findColumnsFromHeader` to true, the task will skip the first two lines and then extract column information from the third line. `columns` will be ignored if this is set to true. | no (default = false if `columns` is set; otherwise null) |
| skipHeaderRows | Integer | If this is set, the task will skip the first `skipHeaderRows` rows. | no (default = 0) |
Be sure to change the `delimiter` to the appropriate delimiter for your data. Like CSV, you must specify the columns and which subset of the columns you want indexed.
To use the ORC input format, load the Druid Orc extension ( [`druid-orc-extensions`](../development/extensions-core/orc.md)).
> To upgrade from versions earlier than 0.15.0 to 0.15.0 or new, read [Migration from 'contrib' extension](../development/extensions-core/orc.md#migration-from-contrib-extension).
| flattenSpec | JSON Object | Specifies flattening configuration for nested ORC data. See [`flattenSpec`](#flattenspec) for more info. | no |
| binaryAsString | Boolean | Specifies if the binary orc column which is not logically marked as a string should be treated as a UTF-8 encoded string. | no (default = false) |
|type| String| This should be set to `parquet` to read Parquet file| yes |
|flattenSpec| JSON Object |Define a [`flattenSpec`](#flattenspec) to extract nested values from a Parquet file. Note that only 'path' expression are supported ('jq' is unavailable).| no (default will auto-discover 'root' level properties) |
| binaryAsString | Boolean | Specifies if the bytes parquet column which is not logically marked as a string or enum type should be treated as a UTF-8 encoded string. | no (default = false) |
|type| String| This should be set to `avro_stream` to read Avro serialized data| yes |
|flattenSpec| JSON Object |Define a [`flattenSpec`](#flattenspec) to extract nested values from a Avro record. Note that only 'path' expression are supported ('jq' is unavailable).| no (default will auto-discover 'root' level properties) |
|`avroBytesDecoder`| JSON Object |Specifies how to decode bytes to Avro record. | yes |
| binaryAsString | Boolean | Specifies if the bytes Avro column which is not logically marked as a string or enum type should be treated as a UTF-8 encoded string. | no (default = false) |
If `type` is not included, the avroBytesDecoder defaults to `schema_repo`.
###### Inline Schema Based Avro Bytes Decoder
> The "schema_inline" decoder reads Avro records using a fixed schema and does not support schema migration. If you
> may need to migrate schemas in the future, consider one of the other decoders, all of which use a message header that
> allows the parser to identify the proper Avro schema for reading records.
This decoder can be used if all the input events can be read using the same schema. In this case, specify the schema in the input task JSON itself, as described below.
```
...
"avroBytesDecoder": {
"type": "schema_inline",
"schema": {
//your schema goes here, for example
"namespace": "org.apache.druid.data",
"name": "User",
"type": "record",
"fields": [
{ "name": "FullName", "type": "string" },
{ "name": "Country", "type": "string" }
]
}
}
...
```
###### Multiple Inline Schemas Based Avro Bytes Decoder
Use this decoder if different input events can have different read schemas. In this case, specify the schema in the input task JSON itself, as described below.
```
...
"avroBytesDecoder": {
"type": "multiple_schemas_inline",
"schemas": {
//your id -> schema map goes here, for example
"1": {
"namespace": "org.apache.druid.data",
"name": "User",
"type": "record",
"fields": [
{ "name": "FullName", "type": "string" },
{ "name": "Country", "type": "string" }
]
},
"2": {
"namespace": "org.apache.druid.otherdata",
"name": "UserIdentity",
"type": "record",
"fields": [
{ "name": "Name", "type": "string" },
{ "name": "Location", "type": "string" }
]
},
...
...
}
}
...
```
Note that it is essentially a map of integer schema ID to avro schema object. This parser assumes that record has following format.
first 1 byte is version and must always be 1.
next 4 bytes are integer schema ID serialized using big-endian byte order.
remaining bytes contain serialized avro message.
##### SchemaRepo Based Avro Bytes Decoder
This Avro bytes decoder first extracts `subject` and `id` from the input message bytes, and then uses them to look up the Avro schema used to decode the Avro record from bytes. For details, see the [schema repo](https://github.com/schema-repo/schema-repo) and [AVRO-1124](https://issues.apache.org/jira/browse/AVRO-1124). You will need an http service like schema repo to hold the avro schema. For information on registering a schema on the message producer side, see `org.apache.druid.data.input.AvroStreamInputRowParserTest#testParse()`.
| Field | Type | Description | Required |
|-------|------|-------------|----------|
| type | String | This should say `schema_repo`. | no |
| subjectAndIdConverter | JSON Object | Specifies how to extract the subject and id from message bytes. | yes |
| schemaRepository | JSON Object | Specifies how to look up the Avro schema from subject and id. | yes |
###### Avro-1124 Subject And Id Converter
This section describes the format of the `subjectAndIdConverter` object for the `schema_repo` Avro bytes decoder.
| Field | Type | Description | Required |
|-------|------|-------------|----------|
| type | String | This should say `avro_1124`. | no |
| topic | String | Specifies the topic of your Kafka stream. | yes |
###### Avro-1124 Schema Repository
This section describes the format of the `schemaRepository` object for the `schema_repo` Avro bytes decoder.
| Field | Type | Description | Required |
|-------|------|-------------|----------|
| type | String | This should say `avro_1124_rest_client`. | no |
| url | String | Specifies the endpoint url of your Avro-1124 schema repository. | yes |
This Avro bytes decoder first extracts a unique `id` from input message bytes, and then uses it to look up the schema in the Schema Registry used to decode the Avro record from bytes.
For details, see the Schema Registry [documentation](http://docs.confluent.io/current/schema-registry/docs/) and [repository](https://github.com/confluentinc/schema-registry).
| Field | Type | Description | Required |
|-------|------|-------------|----------|
| type | String | This should say `schema_registry`. | no |
| url | String | Specifies the url endpoint of the Schema Registry. | yes |
| capacity | Integer | Specifies the max size of the cache (default = Integer.MAX_VALUE). | no |
| urls | Array<String> | Specifies the url endpoints of the multiple Schema Registry instances. | yes(if `url` is not provided) |
| config | Json | To send additional configurations, configured for Schema Registry. This can be supplied via a [DynamicConfigProvider](../operations/dynamic-config-provider.md) | no |
| headers | Json | To send headers to the Schema Registry. This can be supplied via a [DynamicConfigProvider](../operations/dynamic-config-provider.md) | no |
See the [Avro Types](../development/extensions-core/avro.md#avro-types) section for how Avro types are handled in Druid
Configure the Avro OCF `inputFormat` to load Avro OCF data as follows:
| Field | Type | Description | Required |
|-------|------|-------------|----------|
|type| String| This should be set to `avro_ocf` to read Avro OCF file| yes |
|flattenSpec| JSON Object |Define a [`flattenSpec`](#flattenspec) to extract nested values from a Avro records. Note that only 'path' expression are supported ('jq' is unavailable).| no (default will auto-discover 'root' level properties) |
|schema| JSON Object |Define a reader schema to be used when parsing Avro records, this is useful when parsing multiple versions of Avro OCF file data | no (default will decode using the writer schema contained in the OCF file) |
| binaryAsString | Boolean | Specifies if the bytes parquet column which is not logically marked as a string or enum type should be treated as a UTF-8 encoded string. | no (default = false) |
Configure the Protobuf `inputFormat` to load Protobuf data as follows:
| Field | Type | Description | Required |
|-------|------|-------------|----------|
|type| String| This should be set to `protobuf` to read Protobuf serialized data| yes |
|flattenSpec| JSON Object |Define a [`flattenSpec`](#flattenspec) to extract nested values from a Protobuf record. Note that only 'path' expression are supported ('jq' is unavailable).| no (default will auto-discover 'root' level properties) |
|`protoBytesDecoder`| JSON Object |Specifies how to decode bytes to Protobuf record. | yes |
The `flattenSpec` bridges the gap between potentially nested input data (such as JSON, Avro, etc) and Druid's flat data model. It is an object within the `inputFormat` object.
| useFieldDiscovery | If true, interpret all root-level fields as available fields for usage by [`timestampSpec`](./ingestion-spec.md#timestampspec), [`transformSpec`](./ingestion-spec.md#transformspec), [`dimensionsSpec`](./ingestion-spec.md#dimensionsspec), and [`metricsSpec`](./ingestion-spec.md#metricsspec).<br><br>If false, only explicitly specified fields (see `fields`) will be available for use. | `true` |
| fields | Specifies the fields of interest and how they are accessed. See [Field flattening specifications](#field-flattening-specifications) for more detail. | `[]` |
After Druid reads the input data records, it applies the flattenSpec before applying any other specs such as [`timestampSpec`](./ingestion-spec.md#timestampspec), [`transformSpec`](./ingestion-spec.md#transformspec),
> [`dimensionsSpec`](./ingestion-spec.md#dimensionsspec), or [`metricsSpec`](./ingestion-spec.md#metricsspec). Keep this in mind when writing your ingestion spec.
Flattening is only supported for [data formats](data-formats.md) that support nesting, including `avro`, `json`, `orc`,
and `parquet`.
#### Field flattening specifications
Each entry in the `fields` list can have the following components:
| Field | Description | Default |
|-------|-------------|---------|
| type | Options are as follows:<br><br><ul><li>`root`, referring to a field at the root level of the record. Only really useful if `useFieldDiscovery` is false.</li><li>`path`, referring to a field using [JsonPath](https://github.com/jayway/JsonPath) notation. Supported by most data formats that offer nesting, including `avro`, `json`, `orc`, and `parquet`.</li><li>`jq`, referring to a field using [jackson-jq](https://github.com/eiiches/jackson-jq) notation. Only supported for the `json` format.</li></ul> | none (required) |
| name | Name of the field after flattening. This name can be referred to by the [`timestampSpec`](./ingestion-spec.md#timestampspec), [`transformSpec`](./ingestion-spec.md#transformspec), [`dimensionsSpec`](./ingestion-spec.md#dimensionsspec), and [`metricsSpec`](./ingestion-spec.md#metricsspec).| none (required) |
| expr | Expression for accessing the field while flattening. For type `path`, this should be [JsonPath](https://github.com/jayway/JsonPath). For type `jq`, this should be [jackson-jq](https://github.com/eiiches/jackson-jq) notation. For other types, this parameter is ignored. | none (required for types `path` and `jq`) |
#### Notes on flattening
* For convenience, when defining a root-level field, it is possible to define only the field name, as a string, instead of a JSON object. For example, `{"name": "baz", "type": "root"}` is equivalent to `"baz"`.
* Enabling `useFieldDiscovery` will only automatically detect "simple" fields at the root level that correspond to data types that Druid supports. This includes strings, numbers, and lists of strings or numbers. Other types will not be automatically detected, and must be specified explicitly in the `fields` list.
* Duplicate field `name`s are not allowed. An exception will be thrown.
* If `useFieldDiscovery` is enabled, any discovered field with the same name as one already defined in the `fields` list will be skipped, rather than added twice.
* [http://jsonpath.herokuapp.com/](http://jsonpath.herokuapp.com/) is useful for testing `path`-type expressions.
* jackson-jq supports a subset of the full [jq](https://stedolan.github.io/jq/) syntax. Please refer to the [jackson-jq documentation](https://github.com/eiiches/jackson-jq) for details.
## Parser
> The Parser is deprecated for [native batch tasks](./native-batch.md), [Kafka indexing service](../development/extensions-core/kafka-ingestion.md),
and [Kinesis indexing service](../development/extensions-core/kinesis-ingestion.md).
Consider using the [input format](#input-format) instead for these types of ingestion.
This section lists all default and core extension parsers.
|parseSpec | JSON Object | Specifies the timestamp and dimensions of the data (`timeAndDims` and `orc` format) and a `flattenSpec` (`orc` format) | yes|
The parser supports two `parseSpec` formats: `orc` and `timeAndDims`.
`orc` supports auto field discovery and flattening, if specified with a [`flattenSpec`](#flattenspec).
If no `flattenSpec` is specified, `useFieldDiscovery` will be enabled by default. Specifying a `dimensionSpec` is
optional if `useFieldDiscovery` is enabled: if a `dimensionSpec` is supplied, the list of `dimensions` it defines will be
the set of ingested dimensions, if missing the discovered fields will make up the list.
`timeAndDims` parse spec must specify which fields will be extracted as dimensions through the `dimensionSpec`.
| type | String | This should say `parquet`.| yes |
| parseSpec | JSON Object | Specifies the timestamp and dimensions of the data, and optionally, a flatten spec. Valid parseSpec formats are `timeAndDims` and `parquet` | yes |
| binaryAsString | Boolean | Specifies if the bytes parquet column which is not logically marked as a string or enum type should be treated as a UTF-8 encoded string. | no(default = false) |
| binaryAsString | Boolean | Specifies if the bytes parquet column which is not logically marked as a string or enum type should be treated as a UTF-8 encoded string. | no(default = false) |
| parseSpec | JSON Object | Specifies the timestamp and dimensions of the data. The format must be JSON. See [JSON ParseSpec](#json-parsespec) for more configuration options. Note that timeAndDims parseSpec is no longer supported. | yes |
If `type` is not included, the `protoBytesDecoder` defaults to `schema_registry`.
##### File-based Protobuf Bytes Decoder
This Protobuf bytes decoder first read a descriptor file, and then parse it to get schema used to decode the Protobuf record from bytes.
| Field | Type | Description | Required |
|-------|------|-------------|----------|
| type | String | This should say `file`. | yes |
| descriptor | String | Protobuf descriptor file name in the classpath or URL. | yes |
| protoMessageType | String | Protobuf message type in the descriptor. Both short name and fully qualified name are accepted. The parser uses the first message type found in the descriptor if not specified. | no |
This Protobuf bytes decoder first extracts a unique `id` from input message bytes, and then uses it to look up the schema in the Schema Registry used to decode the Avro record from bytes.
For details, see the Schema Registry [documentation](http://docs.confluent.io/current/schema-registry/docs/) and [repository](https://github.com/confluentinc/schema-registry).
| Field | Type | Description | Required |
|-------|------|-------------|----------|
| type | String | This should say `schema_registry`. | yes |
| url | String | Specifies the url endpoint of the Schema Registry. | yes |
| capacity | Integer | Specifies the max size of the cache (default = Integer.MAX_VALUE). | no |
| urls | Array<String> | Specifies the url endpoints of the multiple Schema Registry instances. | yes(if `url` is not provided) |
| config | Json | To send additional configurations, configured for Schema Registry. This can be supplied via a [DynamicConfigProvider](../operations/dynamic-config-provider.md). | no |
| headers | Json | To send headers to the Schema Registry. This can be supplied via a [DynamicConfigProvider](../operations/dynamic-config-provider.md) | no |
> The _jsonLowercase_ parser is deprecated and may be removed in a future version of Druid.
This is a special variation of the JSON ParseSpec that lower cases all the column names in the incoming JSON data. This parseSpec is required if you are updating to Druid 0.7.x from Druid 0.6.x, are directly ingesting JSON with mixed case column names, do not have any ETL in place to lower case those column names, and would like to make queries that include the data you created using 0.6.x and 0.7.x.
| Field | Type | Description | Required |
|-------|------|-------------|----------|
| format | String | This should say `jsonLowercase`. | yes |
| timestampSpec | JSON Object | Specifies the column and format of the timestamp. | yes |
| dimensionsSpec | JSON Object | Specifies the dimensions of the data. | yes |
Be sure to change the `delimiter` to the appropriate delimiter for your data. Like CSV, you must specify the columns and which subset of the columns you want indexed.
"function" : "function(str) { var parts = str.split(\"-\"); return { one: parts[0], two: parts[1] } }"
}
```
Note with the JavaScript parser that data must be fully parsed and returned as a `{key:value}` format in the JS logic.
This means any flattening or parsing multi-dimensional values must be done here.
> JavaScript-based functionality is disabled by default. Please refer to the Druid [JavaScript programming guide](../development/javascript.md) for guidelines about using Druid's JavaScript functionality, including instructions on how to enable it.
