Camel Components

Google Cloud Speech To Text

Since Camel 4.19

Only producer is supported

The Google Cloud Speech To Text component provides access to Google Cloud Speech-to-Text API via the Google Cloud Speech Client for Java.

Maven users will need to add the following dependency to their pom.xml for this component:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-google-speech-to-text</artifactId>
    <!-- use the same version as your Camel core version -->
    <version>x.x.x</version>
</dependency>

Authentication Configuration

Google Cloud Speech To Text component authentication is targeted for use with the GCP Service Accounts. For more information, please refer to Google Cloud Authentication.

When you have the service account key, you can provide authentication credentials to your application code. Google security credentials can be set through the component endpoint:

Java-only: constructing the endpoint URI programmatically
String endpoint = "google-speech-to-text://recognize?serviceAccountKey=/home/user/Downloads/my-key.json";

Or by setting the environment variable GOOGLE_APPLICATION_CREDENTIALS :

export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/my-key.json"

URI Format

google-speech-to-text://operation[?options]

You can append query options to the URI in the following format, ?options=value&option2=value&…​

For example, in order to perform speech recognition on audio data, use the following snippet:

  • Java

  • XML

  • YAML

from("direct:start")
    .to("google-speech-to-text://recognize?serviceAccountKey=/home/user/Downloads/my-key.json");
<route>
  <from uri="direct:start"/>
  <to uri="google-speech-to-text://recognize?serviceAccountKey=/home/user/Downloads/my-key.json"/>
</route>
- route:
    from:
      uri: direct:start
      steps:
        - to:
            uri: google-speech-to-text://recognize
            parameters:
              serviceAccountKey: /home/user/Downloads/my-key.json

Configuring Options

Camel components are configured on two separate levels:

  • component level

  • endpoint level

Configuring Component Options

At the component level, you set general and shared configurations that are, then, inherited by the endpoints. It is the highest configuration level.

For example, a component may have security settings, credentials for authentication, urls for network connection and so forth.

Some components only have a few options, and others may have many. Because components typically have pre-configured defaults that are commonly used, then you may often only need to configure a few options on a component; or none at all.

You can configure components using:

  • the Component DSL.

  • in a configuration file (application.properties, *.yaml files, etc).

  • directly in the Java code.

Configuring Endpoint Options

You usually spend more time setting up endpoints because they have many options. These options help you customize what you want the endpoint to do. The options are also categorized into whether the endpoint is used as a consumer (from), as a producer (to), or both.

Configuring endpoints is most often done directly in the endpoint URI as path and query parameters. You can also use the Endpoint DSL and DataFormat DSL as a type safe way of configuring endpoints and data formats in Java.

A good practice when configuring options is to use Property Placeholders.

Property placeholders provide a few benefits:

  • They help prevent using hardcoded urls, port numbers, sensitive information, and other settings.

  • They allow externalizing the configuration from the code.

  • They help the code to become more flexible and reusable.

The following two sections list all the options, firstly for the component followed by the endpoint.

Component Options

The Google Cloud Speech To Text component supports the following options which are listed below.

Name Description Default Type

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

autowiredEnabled (advanced)

Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc.

true

boolean

Endpoint Options

The Google Cloud Speech To Text endpoint is configured using URI syntax:

google-speech-to-text:operation

With the following path and query parameters:

Path Parameters

Name Description Default Type

operation (common)

Required The operation name.

String

Query Parameters

Name Description Default Type

serviceAccountKey (common)

Service account key to authenticate an application as a service account.

String

encoding (producer)

The encoding of the audio data. Supported values: LINEAR16, FLAC, MULAW, AMR, AMR_WB, OGG_OPUS, SPEEX_WITH_HEADER_BYTE, WEBM_OPUS, MP3.

LINEAR16

String

languageCode (producer)

The language of the audio data as a BCP-47 language tag (e.g., en-US, fr-FR).

en-US

String

pojoRequest (producer)

Specifies if the request is a pojo request.

false

boolean

sampleRateHertz (producer)

The sample rate in Hertz of the audio data. Valid values range from 8000 to 48000.

Integer

lazyStartProducer (producer (advanced))

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

client (advanced)

Autowired The client to use during service invocation.

SpeechClient

Message Headers

The Google Cloud Speech To Text component supports the following message header(s), which is/are listed below:

Name Description Default Type

CamelGoogleCloudSpeechToTextOperation (producer)

Constant: OPERATION

The operation to perform.

Enum values:

  • recognize

GoogleCloudSpeechToTextOperations

CamelGoogleCloudSpeechToTextResponseObject (producer)

Constant: RESPONSE_OBJECT

The response object resulting from the Google Cloud Speech-to-Text API invocation.

RecognizeResponse

Message Body

The message body at each side of the Google Cloud Speech To Text component: Consumer is the body of the messages the consumer creates, Consumer reply the bodies a consumer that answers its caller can reply with, Producer input the bodies the producer can send or write, and Producer output the body after the producer.

Side Body Description

Producer input

bytes, stream or file

The audio to transcribe, sent inline in the encoding and sample rate of the encoding and sampleRateHertz options (LINEAR16 by default). A stream or a file is read into bytes and a String is sent as its bytes, a Map, a POJO or no body fails. With pojoRequest=true a RecognizeRequest of the Google Cloud SDK: another body fails.

  • With pojoRequest=true: pojo (com.google.cloud.speech.v1.RecognizeRequest)

Producer output

text (java.lang.String)

The transcript: the best alternative of each result, one line per result, or an empty String when nothing is recognized, also with pojoRequest=true. The RecognizeResponse is in the CamelGoogleCloudSpeechToTextResponseObject header.

The bodies are the ones with the default options. A side that is not listed is not known, and tooling does not guess it. The carriers are described in the Camel Catalog.

Usage

Message body

The message body should contain the audio data as a byte[].

When pojoRequest=true, the body should be a com.google.cloud.speech.v1.RecognizeRequest instance instead.

Google Cloud Speech To Text Producer operations

Google Cloud Speech To Text component provides the following operation on the producer side:

  • recognize

The operation is specified as part of the endpoint URI (e.g., google-speech-to-text://recognize). You can override the operation at runtime by setting the GoogleCloudSpeechToTextOperation message header.

Advanced component configuration

If you need to have more control over the SpeechClient instance configuration, you can create your own instance and refer to it in your Camel google-speech-to-text component configuration:

  • Java

  • XML

  • YAML

from("direct:start")
    .to("google-speech-to-text://recognize?client=#mySpeechClient");
<route>
  <from uri="direct:start"/>
  <to uri="google-speech-to-text://recognize?client=#mySpeechClient"/>
</route>
- route:
    from:
      uri: direct:start
      steps:
        - to:
            uri: google-speech-to-text://recognize
            parameters:
              client: "#mySpeechClient"

Google Cloud Speech To Text Producer Operation examples

  • recognize: this operation transcribes audio data to text. The message body should contain the audio data as a byte[].

  • Java

  • XML

  • YAML

from("direct:start")
    .to("google-speech-to-text://recognize?serviceAccountKey=/home/user/Downloads/my-key.json&encoding=LINEAR16&sampleRateHertz=16000&languageCode=en-US")
    .log("body:${body}")
    .to("mock:result");
<route>
  <from uri="direct:start"/>
  <to uri="google-speech-to-text://recognize?serviceAccountKey=/home/user/Downloads/my-key.json&amp;encoding=LINEAR16&amp;sampleRateHertz=16000&amp;languageCode=en-US"/>
  <log message="body:${body}"/>
  <to uri="mock:result"/>
</route>
- route:
    from:
      uri: direct:start
      steps:
        - to:
            uri: google-speech-to-text://recognize
            parameters:
              serviceAccountKey: /home/user/Downloads/my-key.json
              encoding: LINEAR16
              sampleRateHertz: 16000
              languageCode: en-US
        - log:
            message: "body:${body}"
        - to:
            uri: mock:result

This operation will return the transcribed text as a String. The full RecognizeResponse is available via the GoogleCloudSpeechToTextResponseObject message header.

  • Using different audio encodings:

  • Java

  • XML

  • YAML

from("direct:start")
    .to("google-speech-to-text://recognize?serviceAccountKey=/home/user/Downloads/my-key.json&encoding=FLAC&languageCode=fr-FR")
    .log("body:${body}")
    .to("mock:result");
<route>
  <from uri="direct:start"/>
  <to uri="google-speech-to-text://recognize?serviceAccountKey=/home/user/Downloads/my-key.json&amp;encoding=FLAC&amp;languageCode=fr-FR"/>
  <log message="body:${body}"/>
  <to uri="mock:result"/>
</route>
- route:
    from:
      uri: direct:start
      steps:
        - to:
            uri: google-speech-to-text://recognize
            parameters:
              serviceAccountKey: /home/user/Downloads/my-key.json
              encoding: FLAC
              languageCode: fr-FR
        - log:
            message: "body:${body}"
        - to:
            uri: mock:result

  • Using POJO request for full control:

Java-only: Google Cloud SDK RecognizeRequest builder
from("direct:start")
    .process(exchange -> {
        RecognitionConfig config = RecognitionConfig.newBuilder()
            .setEncoding(RecognitionConfig.AudioEncoding.LINEAR16)
            .setSampleRateHertz(16000)
            .setLanguageCode("en-US")
            .build();
        RecognitionAudio audio = RecognitionAudio.newBuilder()
            .setContent(ByteString.copyFrom(audioData))
            .build();
        RecognizeRequest request = RecognizeRequest.newBuilder()
            .setConfig(config)
            .setAudio(audio)
            .build();
        exchange.getIn().setBody(request);
    })
    .to("google-speech-to-text://recognize?serviceAccountKey=/home/user/Downloads/my-key.json&pojoRequest=true")
    .log("body:${body}")
    .to("mock:result");

When using pojoRequest=true, the body should be a RecognizeRequest and the transcribed text is returned as the body.

  • Overriding the operation at runtime via header:

  • Java

  • XML

  • YAML

from("direct:start")
    .setHeader("CamelGoogleCloudSpeechToTextOperation", constant("recognize"))
    .to("google-speech-to-text://recognize?serviceAccountKey=/home/user/Downloads/my-key.json")
    .log("body:${body}")
    .to("mock:result");
<route>
  <from uri="direct:start"/>
  <setHeader name="CamelGoogleCloudSpeechToTextOperation">
    <constant>recognize</constant>
  </setHeader>
  <to uri="google-speech-to-text://recognize?serviceAccountKey=/home/user/Downloads/my-key.json"/>
  <log message="body:${body}"/>
  <to uri="mock:result"/>
</route>
- route:
    from:
      uri: direct:start
      steps:
        - setHeader:
            name: CamelGoogleCloudSpeechToTextOperation
            constant: recognize
        - to:
            uri: google-speech-to-text://recognize
            parameters:
              serviceAccountKey: /home/user/Downloads/my-key.json
        - log:
            message: "body:${body}"
        - to:
            uri: mock:result