schema_registry_encode

Automatically encodes and validates messages with schemas from a Confluent Schema Registry service.

Introduced in version 3.58.0.

Common
Advanced

# Common config fields, showing default values
label: ""
schema_registry_encode:
  url: "" # No default (required)
  subject: foo # No default (required)
  refresh_period: 10m

# Advanced config fields, showing default values
label: ""
schema_registry_encode:
  url: "" # No default (required)
  subject: foo # No default (required)
  refresh_period: 10m
  avro_raw_json: false
  oauth:
    enabled: false
    consumer_key: ""
    consumer_secret: ""
    access_token: ""
    access_token_secret: ""
  basic_auth:
    enabled: false
    username: ""
    password: ""
  jwt:
    enabled: false
    private_key_file: ""
    signing_method: ""
    claims: {}
    headers: {}
  tls:
    skip_cert_verify: false
    enable_renegotiation: false
    root_cas: ""
    root_cas_file: ""
    client_certs: []

Encodes messages automatically from schemas obtains from a Confluent Schema Registry service by polling the service for the latest schema version for target subjects.

If a message fails to encode under the schema then it will remain unchanged and the error can be caught using error handling methods.

Avro, Protobuf and Json schemas are supported, all are capable of expanding from schema references as of v4.22.0.

Avro JSON format

By default this processor expects documents formatted as Avro JSON when encoding with Avro schemas. In this format the value of a union is encoded in JSON as follows:

if its type is null, then it is encoded as a JSON null;
otherwise it is encoded as a JSON object with one name/value pair whose name is the type’s name and whose value is the recursively encoded value. For Avro’s named types (record, fixed or enum) the user-specified name is used, for other types the type name is used.

For example, the union schema ["null","string","Foo"], where Foo is a record name, would encode:

null as null;
the string "a" as \{"string": "a"}; and
a Foo instance as \{"Foo": {...}}, where {...} indicates the JSON encoding of a Foo instance.

However, it is possible to instead consume documents in standard/raw JSON format by setting the field avro_raw_json to true.

Known issues

Important! There is an outstanding issue in the avro serializing library that Redpanda Connect uses which means it doesn’t encode logical types correctly. It’s still possible to encode logical types that are in-line with the spec if avro_raw_json is set to true, though now of course non-logical types will not be in-line with the spec.

Protobuf format

This processor encodes protobuf messages either from any format parsed within Redpanda Connect (encoded as JSON by default), or from raw JSON documents, you can read more about JSON mapping of protobuf messages here: [get in touch](https://developers.google.com/protocol-buffers/docs/proto3#json

Multiple message support

When a target subject presents a protobuf schema that contains multiple messages it becomes ambiguous which message definition a given input data should be encoded against. In such scenarios Redpanda Connect will attempt to encode the data against each of them and select the first to successfully match against the data, this process currently ignores all nested message definitions. In order to speed up this exhaustive search the last known successful message will be attempted first for each subsequent input.

We will be considering alternative approaches in future so please https://redpanda.com/slack) with thoughts and feedback.

Fields

`url`

The base URL of the schema registry service.

Type: string

`subject`

The schema subject to derive schemas from. This field supports interpolation functions.

Type: string

# Examples

subject: foo

subject: ${! meta("kafka_topic") }

`refresh_period`

The period after which a schema is refreshed for each subject, this is done by polling the schema registry service.

Type: string

Default: "10m"

# Examples

refresh_period: 60s

refresh_period: 1h

`avro_raw_json`

Whether messages encoded in Avro format should be parsed as normal JSON (“json that meets the expectations of regular internet json”) rather than Avro JSON. If true the schema returned from the subject should be parsed as standard json instead of as avro json. There is a comment in goavro, the underlining library used for avro serialization, that explains in more detail the difference between standard json and avro json.

Type: bool

Default: false Requires version 3.59.0 or newer

`oauth`

Allows you to specify open authentication via OAuth version 1.

Type: object

Requires version 4.7.0 or newer

`oauth.enabled`

Whether to use OAuth version 1 in requests.

Type: bool

Default: false

`oauth.consumer_key`

A value used to identify the client to the service provider.

Type: string

Default: ""

`oauth.consumer_secret`

A secret used to establish ownership of the consumer key.

Type: string

Default: ""

`oauth.access_token`

A value used to gain access to the protected resources on behalf of the user.

Type: string

Default: ""

`oauth.access_token_secret`

A secret provided in order to establish ownership of a given access token.

Add optional key/value headers to the JWT.

Type: object

Default: {}

`tls`

Custom TLS settings can be used to override system defaults.

Type: object

`tls.skip_cert_verify`

Whether to skip server side certificate verification.

Type: bool

Default: false

`tls.enable_renegotiation`

Whether to allow the remote server to repeatedly request renegotiation. Enable this option if you’re seeing the error message local error: tls: no renegotiation.

Type: bool

Default: false Requires version 3.45.0 or newer

`tls.root_cas`

An optional root certificate authority to use. This is a string, representing a certificate chain from the parent trusted root certificate, to possible intermediate signing certificates, to the host certificate.

Type: string

Default: ""

# Examples

root_cas: |-
  -----BEGIN CERTIFICATE-----
  ...
  -----END CERTIFICATE-----

`tls.root_cas_file`

An optional path of a root certificate authority file to use. This is a file, often with a .pem extension, containing a certificate chain from the parent trusted root certificate, to possible intermediate signing certificates, to the host certificate.

Type: string

Default: ""

# Examples

root_cas_file: ./root_cas.pem

`tls.client_certs`

A list of client certificates to use. For each certificate either the fields cert and key, or cert_file and key_file should be specified, but not both.

Type: array

Default: []

# Examples

client_certs:
  - cert: foo
    key: bar

client_certs:
  - cert_file: ./example.pem
    key_file: ./example.key

`tls.client_certs[].cert`

A plain text certificate to use.

Type: string

Default: ""

`tls.client_certs[].key`

A plain text certificate key to use.

Type: string

Default: ""

`tls.client_certs[].cert_file`

The path of a certificate to use.

Type: string

Default: ""

`tls.client_certs[].key_file`

The path of a certificate key to use.

Type: string

Default: ""

`tls.client_certs[].password`

A plain text password for when the private key is password encrypted in PKCS#1 or PKCS#8 format. The obsolete pbeWithMD5AndDES-CBC algorithm is not supported for the PKCS#8 format.

Because the obsolete pbeWithMD5AndDES-CBC algorithm does not authenticate the ciphertext, it is vulnerable to padding oracle attacks that can let an attacker recover the plaintext.

Type: string

Default: ""

# Examples

password: foo

password: ${KEY_PASSWORD}