Connect
Self-Managed Only

protobuf

Performs conversions to or from a protobuf message. This processor uses reflection, meaning conversions can be made directly from the target .proto files.

The main functionality of this processor is to map to and from JSON documents. For how protobuf messages map to JSON, see ProtoJSON Format and Examples.

Using reflection for processing protobuf messages in this way is less performant than generating and using native code. Therefore when performance is critical it is recommended that you use Redpanda Connect plugins instead for processing protobuf messages natively. For an example, see the Redpanda Connect plugin example.

The processor will ignore any files that begin with a dot ("."), a convention for hidden files, when loading protocol buffer definitions.

Operators

to_json

Converts protobuf messages into serialized proto3 JSON.

from_json

Attempts to create a target protobuf message from a serialized proto3 JSON.

decode

Converts protobuf messages into a generic structured message. This makes it easier to manipulate the contents of the document within Redpanda Connect. This differs from to_json in the following ways:

  • 64 bit numbers are not converted into strings

  • Bytes and google.protobuf.Timestamp types are preserved (not encoded as strings unless serialized)

This operator is also considerably faster in scenario where you manipulate the data as the data does not need to be serialized then deserialized like with the to_json operator.

  • Common

  • Advanced

processor:
  label: ""
  protobuf:
    operator: "" # No default (required)
    message: "" # No default (required)
    discard_unknown: false
    use_proto_names: false
    import_paths: []
    use_enum_numbers: false
    bsr: []
processor:
  label: ""
  protobuf:
    operator: "" # No default (required)
    message: "" # No default (required)
    discard_unknown: false
    use_proto_names: false
    import_paths: []
    use_enum_numbers: false
    bsr: []

Fields

bsr[]

Buf Schema Registry configuration. Either this field or import_paths must be populated. Note that this field is an array, and multiple BSR configurations can be provided.

Requires version 4.63.0 or later.

Type: array<object>

Default: []

bsr[].api_key

Buf Schema Registry server API key, can be left blank for a public registry.

This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Secrets.

Type: string

Default: ""

bsr[].module

Module to fetch from a Buf Schema Registry, for example, 'buf.build/exampleco/mymodule'.

Type: string

bsr[].url

Buf Schema Registry URL, leave blank to extract from module.

Type: string

Default: ""

bsr[].version

Version to retrieve from the Buf Schema Registry, leave blank for latest.

Type: string

Default: ""

discard_unknown

When set to true, the from_json operator discards fields that are unknown to the schema.

Requires version 4.24.0 or later.

Type: bool

Default: false

import_paths[]

A list of directories that contain .proto files, including all definitions required for parsing the target message. If left empty, the current directory is used. This processor walks each listed directory and imports all .proto files it finds. Either this field or bsr must be populated.

Type: array<string>

Default: []

message

The fully-qualified name of the protobuf message to convert from or to JSON.

Type: string

operator

The operator to execute.

Type: string

Options: to_json, from_json, decode

use_enum_numbers

When set to true, the to_json or decode operator deserializes enumeration fields as their numerical values instead of their string names. For example, an enum field with a value of ENUM_VALUE_ONE is represented as 1 in the JSON output.

Requires version 4.53.0 or later.

Type: bool

Default: false

use_proto_names

When set to true, the to_json or decode operator deserializes fields exactly as named in the schema file.

Requires version 4.24.0 or later.

Type: bool

Default: false

Examples

JSON to Protobuf using Schema from Disk

If we have the following protobuf definition within a directory called testing/schema:

syntax = "proto3";
package testing;

import "google/protobuf/timestamp.proto";

message Person {
  string first_name = 1;
  string last_name = 2;
  string full_name = 3;
  int32 age = 4;
  int32 id = 5; // Unique ID number for this person.
  string email = 6;

  google.protobuf.Timestamp last_updated = 7;
}

And a stream of JSON documents of the form:

{
	"firstName": "caleb",
	"lastName": "quaye",
	"email": "caleb@myspace.com"
}

We can convert the documents into protobuf messages with the following config:

pipeline:
  processors:
    - protobuf:
        operator: from_json
        message: testing.Person
        import_paths: [ testing/schema ]

Protobuf to JSON using Schema from Disk

If we have the following protobuf definition within a directory called testing/schema:

syntax = "proto3";
package testing;

import "google/protobuf/timestamp.proto";

message Person {
  string first_name = 1;
  string last_name = 2;
  string full_name = 3;
  int32 age = 4;
  int32 id = 5; // Unique ID number for this person.
  string email = 6;

  google.protobuf.Timestamp last_updated = 7;
}

And a stream of protobuf messages of the type Person, we could convert them into JSON documents of the format:

{
	"firstName": "caleb",
	"lastName": "quaye",
	"email": "caleb@myspace.com"
}

With the following config:

pipeline:
  processors:
    - protobuf:
        operator: to_json
        message: testing.Person
        import_paths: [ testing/schema ]

JSON to Protobuf using Buf Schema Registry

If we have the following protobuf definition within a BSR module hosted at buf.build/exampleco/mymodule:

syntax = "proto3";
package testing;

import "google/protobuf/timestamp.proto";

message Person {
  string first_name = 1;
  string last_name = 2;
  string full_name = 3;
  int32 age = 4;
  int32 id = 5; // Unique ID number for this person.
  string email = 6;

  google.protobuf.Timestamp last_updated = 7;
}

And a stream of JSON documents of the form:

{
	"firstName": "caleb",
	"lastName": "quaye",
	"email": "caleb@myspace.com"
}

We can convert the documents into protobuf messages with the following config:

pipeline:
  processors:
    - protobuf:
        operator: from_json
        message: testing.Person
        bsr:
          - module: buf.build/exampleco/mymodule
            api_key: xxx

Protobuf to JSON using Buf Schema Registry

If we have the following protobuf definition within a BSR module hosted at buf.build/exampleco/mymodule:

syntax = "proto3";
package testing;

import "google/protobuf/timestamp.proto";

message Person {
  string first_name = 1;
  string last_name = 2;
  string full_name = 3;
  int32 age = 4;
  int32 id = 5; // Unique ID number for this person.
  string email = 6;

  google.protobuf.Timestamp last_updated = 7;
}

And a stream of protobuf messages of the type Person, we could convert them into JSON documents of the format:

{
	"firstName": "caleb",
	"lastName": "quaye",
	"email": "caleb@myspace.com"
}

With the following config:

pipeline:
  processors:
    - protobuf:
        operator: to_json
        message: testing.Person
        bsr:
          - module: buf.build/exampleco/mymodule
            api_key: xxxx