schema_registry_decode

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

Common

# Common config fields, showing default values
label: ""
schema_registry_decode:
  avro:
    raw_unions: false # No default (optional)
    preserve_logical_types: false
    translate_kafka_connect_types: false
  protobuf:
    use_proto_names: false
    use_enum_numbers: false
    emit_unpopulated: false
    emit_default_values: false
  cache_duration: 10m
  url: "" # No default (required)

Advanced

# Advanced config fields, showing default values
label: ""
schema_registry_decode:
  avro:
    raw_unions: false # No default (optional)
    preserve_logical_types: false
    translate_kafka_connect_types: false
    mapping: | # No default (optional)
      map isDebeziumTimestampType {
        root = this.type == "long" && this."connect.name" == "io.debezium.time.Timestamp" && !this.exists("logicalType")
      }
      map debeziumTimestampToAvroTimestamp {
        let mapped_fields = this.fields.or([]).map_each(item -> item.apply("debeziumTimestampToAvroTimestamp"))
        root = match {
          this.type == "record" => this.assign({"fields": $mapped_fields})
          this.type.type() == "array" => this.assign({"type": this.type.map_each(item -> item.apply("debeziumTimestampToAvroTimestamp"))})
          # Add a logical type so that it's decoded as a timestamp instead of a long.
          this.type.type() == "object" && this.type.apply("isDebeziumTimestampType") => this.merge({"type":{"logicalType": "timestamp-millis"}})
          _ => this
        }
      }
      root = this.apply("debeziumTimestampToAvroTimestamp")
  protobuf:
    use_proto_names: false
    use_enum_numbers: false
    emit_unpopulated: false
    emit_default_values: false
  cache_duration: 10m
  url: "" # No default (required)
  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: []

Decodes messages automatically from a schema stored within a Confluent Schema Registry service by extracting a schema ID from the message and obtaining the associated schema from the registry. If a message fails to match against 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

This processor creates documents formatted as Avro JSON when decoding 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 create documents in standard/raw JSON format by setting the field avro_raw_json to true.

Protobuf format

This processor decodes protobuf messages to JSON documents, you can read more about JSON mapping of protobuf messages here: https://developers.google.com/protocol-buffers/docs/proto3#json

Metadata

This processor also adds the following metadata to each outgoing message:

schema_id: the ID of the schema in the schema registry that was associated with the message.

Fields

avro

Configuration for how to decode schemas that are of type AVRO.

Type: object

avro.raw_unions

Whether avro messages should be decoded into normal JSON (“json that meets the expectations of regular internet json”) rather than JSON as specified in the Avro Spec.

For example, if there is a union schema ["null", "string", "Foo"] where Foo is a record name, with raw_unions as false (the default) you get:

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

When raw_unions is set to true then the above union schema is decoded as the following:

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

Type: bool

avro.preserve_logical_types

Whether logical types should be preserved or transformed back into their primitive type. By default, decimals are decoded as raw bytes and timestamps are decoded as plain integers. Setting this field to true keeps decimal types as numbers in bloblang and timestamps as time values.

Type: bool

Default: false

avro.translate_kafka_connect_types

Only valid if preserve_logical_types is true. This decodes various Kafka Connect types into their bloblang equivalents when not representable by standard logical types according to the Avro standard.

Types that are currently translated:

.Debezium Custom Temporal Types

Type: bool

Default: false

avro.mapping

A custom mapping to apply to Avro schemas JSON representation. This is useful to transform custom types emitted by other tools into standard avro.

Type: string

# Examples

mapping: |2
  map isDebeziumTimestampType {
    root = this.type == "long" && this."connect.name" == "io.debezium.time.Timestamp" && !this.exists("logicalType")
  }
  map debeziumTimestampToAvroTimestamp {
    let mapped_fields = this.fields.or([]).map_each(item -> item.apply("debeziumTimestampToAvroTimestamp"))
    root = match {
      this.type == "record" => this.assign({"fields": $mapped_fields})
      this.type.type() == "array" => this.assign({"type": this.type.map_each(item -> item.apply("debeziumTimestampToAvroTimestamp"))})
      # Add a logical type so that it's decoded as a timestamp instead of a long.
      this.type.type() == "object" && this.type.apply("isDebeziumTimestampType") => this.merge({"type":{"logicalType": "timestamp-millis"}})
      _ => this
    }
  }
  root = this.apply("debeziumTimestampToAvroTimestamp")

protobuf

Configuration for how to decode schemas that are of type PROTOBUF.

Type: object

protobuf.use_proto_names

Use proto field name instead of lowerCamelCase name.

Type: bool

Default: false

protobuf.use_enum_numbers

Emits enum values as numbers.

Type: bool

Default: false

protobuf.emit_unpopulated

Whether to emit unpopulated fields. It does not emit unpopulated oneof fields or unpopulated extension fields.

Type: bool

Default: false

protobuf.emit_default_values

Whether to emit default-valued primitive fields, empty lists, and empty maps. emit_unpopulated takes precedence over emit_default_values

Type: bool

Default: false

cache_duration

The duration after which a schema is considered stale and will be removed from the cache.

Type: string

Default: "10m"

# Examples

cache_duration: 1h

cache_duration: 5m

url

The base URL of the schema registry service.

Type: string

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.

Sensitive Information

This field contains sensitive information that usually shouldn’t be added to a config directly, read our secrets page for more info.

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.

Sensitive Information

This field contains sensitive information that usually shouldn’t be added to a config directly, read our secrets page for more info.

Type: string

Default: ""

basic_auth

Allows you to specify basic authentication.

Type: object

Requires version 4.7.0 or newer

basic_auth.enabled

Whether to use basic authentication in requests.

Type: bool

Default: false

basic_auth.username

A username to authenticate as.

Type: string

Default: ""

basic_auth.password

A password to authenticate with.

Sensitive Information

This field contains sensitive information that usually shouldn’t be added to a config directly, read our secrets page for more info.

Type: string

Default: ""

jwt

BETA: Allows you to specify JWT authentication.

Type: object

Requires version 4.7.0 or newer

jwt.enabled

Whether to use JWT authentication in requests.

Type: bool

Default: false

jwt.private_key_file

A file with the PEM encoded via PKCS1 or PKCS8 as private key.

Type: string

Default: ""

jwt.signing_method

A method used to sign the token such as RS256, RS384, RS512 or EdDSA.

Type: string

Default: ""

jwt.claims

A value used to identify the claims that issued the JWT.

Type: object

Default: {}

jwt.headers

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.

Sensitive Information

This field contains sensitive information that usually shouldn’t be added to a config directly, read our secrets page for more info.

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.

Sensitive Information

This field contains sensitive information that usually shouldn’t be added to a config directly, read our secrets page for more info.

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.

Sensitive Information

This field contains sensitive information that usually shouldn’t be added to a config directly, read our secrets page for more info.

Type: string

Default: ""

# Examples

password: foo

password: ${KEY_PASSWORD}