Slack

Since Camel 2.16

Both producer and consumer are supported

The Slack component allows you to connect to an instance of Slack and to send and receive the messages.

To send a message contained in the message body a pre established Slack incoming webhook must be configured in Slack.

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

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

URI format

To send a message to a channel.

slack:#channel[?options]

To send a direct message to a slack user.

slack:@userID[?options]

Configuring Options

Camel components are configured on two separate levels:

  • component level

  • endpoint level

Configuring Component Options

The component level is the highest level which holds general and common configurations that are inherited by the endpoints. 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.

Configuring components can be done with the Component DSL, in a configuration file (application.properties|yaml), or directly with Java code.

Configuring Endpoint Options

Where you find yourself configuring the most is on endpoints, as endpoints often have many options, which allows you to configure what you need the endpoint to do. The options are also categorized into whether the endpoint is used as consumer (from) or as a producer (to), or used for 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, which allows to not hardcode urls, port numbers, sensitive information, and other settings. In other words placeholders allows to externalize the configuration from your code, and gives more flexibility and reuse.

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

Component Options

The Slack component supports 7 options, which are listed below.

Name Description Default Type

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions (if possible) occurred while the Camel consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. Important: This is only possible if the 3rd party component allows Camel to be alerted if an exception was thrown. Some components handle this internally only, and therefore bridgeErrorHandler is not possible. In other situations we may improve the Camel component to hook into the 3rd party component and make this possible for future releases. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

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

healthCheckConsumerEnabled (health)

Used for enabling or disabling all consumer based health checks from this component.

true

boolean

healthCheckProducerEnabled (health)

Used for enabling or disabling all producer based health checks from this component. Notice: Camel has by default disabled all producer based health-checks. You can turn on producer checks globally by setting camel.health.producersEnabled=true.

true

boolean

token (token)

The token to access Slack. This app needs to have channels:history, groups:history, im:history, mpim:history, channels:read, groups:read, im:read and mpim:read permissions. The User OAuth Token is the kind of token needed.

String

webhookUrl (webhook)

The incoming webhook URL.

String

Endpoint Options

The Slack endpoint is configured using URI syntax:

slack:channel

with the following path and query parameters:

Path Parameters (1 parameters)

Name Description Default Type

channel (common)

Required The channel name (syntax #name) or slack user (syntax userName) to send a message directly to an user.

String

Query Parameters (29 parameters)

Name Description Default Type

token (common)

The token to access Slack. This app needs to have channels:history, groups:history, im:history, mpim:history, channels:read, groups:read, im:read and mpim:read permissions. The User OAuth Token is the kind of token needed.

String

conversationType (consumer)

Type of conversation.

Enum values:

  • PUBLIC_CHANNEL

  • PRIVATE_CHANNEL

  • MPIM

  • IM

PUBLIC_CHANNEL

ConversationType

maxResults (consumer)

The Max Result for the poll.

10

String

naturalOrder (consumer)

Create exchanges in natural order (oldest to newest) or not.

false

boolean

sendEmptyMessageWhenIdle (consumer)

If the polling consumer did not poll any files, you can enable this option to send an empty message (no body) instead.

false

boolean

serverUrl (consumer)

The Server URL of the Slack instance.

https://slack.com

String

bridgeErrorHandler (consumer (advanced))

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions (if possible) occurred while the Camel consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. Important: This is only possible if the 3rd party component allows Camel to be alerted if an exception was thrown. Some components handle this internally only, and therefore bridgeErrorHandler is not possible. In other situations we may improve the Camel component to hook into the 3rd party component and make this possible for future releases. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

exceptionHandler (consumer (advanced))

To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this option is not in use. By default the consumer will deal with exceptions, that will be logged at WARN or ERROR level and ignored.

ExceptionHandler

exchangePattern (consumer (advanced))

Sets the exchange pattern when the consumer creates an exchange.

Enum values:

  • InOnly

  • InOut

ExchangePattern

pollStrategy (consumer (advanced))

A pluggable org.apache.camel.PollingConsumerPollingStrategy allowing you to provide your custom implementation to control error handling usually occurred during the poll operation before an Exchange have been created and being routed in Camel.

PollingConsumerPollStrategy

iconEmoji (producer)

Deprecated Use a Slack emoji as an avatar.

String

iconUrl (producer)

Deprecated The avatar that the component will use when sending message to a channel or user.

String

username (producer)

Deprecated This is the username that the bot will have when sending messages to a channel or user.

String

webhookUrl (producer)

The incoming webhook URL.

String

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

backoffErrorThreshold (scheduler)

The number of subsequent error polls (failed due some error) that should happen before the backoffMultipler should kick-in.

int

backoffIdleThreshold (scheduler)

The number of subsequent idle polls that should happen before the backoffMultipler should kick-in.

int

backoffMultiplier (scheduler)

To let the scheduled polling consumer backoff if there has been a number of subsequent idles/errors in a row. The multiplier is then the number of polls that will be skipped before the next actual attempt is happening again. When this option is in use then backoffIdleThreshold and/or backoffErrorThreshold must also be configured.

int

delay (scheduler)

Milliseconds before the next poll.

10000

long

greedy (scheduler)

If greedy is enabled, then the ScheduledPollConsumer will run immediately again, if the previous run polled 1 or more messages.

false

boolean

initialDelay (scheduler)

Milliseconds before the first poll starts.

1000

long

repeatCount (scheduler)

Specifies a maximum limit of number of fires. So if you set it to 1, the scheduler will only fire once. If you set it to 5, it will only fire five times. A value of zero or negative means fire forever.

0

long

runLoggingLevel (scheduler)

The consumer logs a start/complete log line when it polls. This option allows you to configure the logging level for that.

Enum values:

  • TRACE

  • DEBUG

  • INFO

  • WARN

  • ERROR

  • OFF

TRACE

LoggingLevel

scheduledExecutorService (scheduler)

Allows for configuring a custom/shared thread pool to use for the consumer. By default each consumer has its own single threaded thread pool.

ScheduledExecutorService

scheduler (scheduler)

To use a cron scheduler from either camel-spring or camel-quartz component. Use value spring or quartz for built in scheduler.

none

Object

schedulerProperties (scheduler)

To configure additional properties when using a custom scheduler or any of the Quartz, Spring based scheduler.

Map

startScheduler (scheduler)

Whether the scheduler should be auto started.

true

boolean

timeUnit (scheduler)

Time unit for initialDelay and delay options.

Enum values:

  • NANOSECONDS

  • MICROSECONDS

  • MILLISECONDS

  • SECONDS

  • MINUTES

  • HOURS

  • DAYS

MILLISECONDS

TimeUnit

useFixedDelay (scheduler)

Controls if fixed delay or fixed rate is used. See ScheduledExecutorService in JDK for details.

true

boolean

Configuring in Spring XML

The SlackComponent with XML must be configured as a Spring or Blueprint bean that contains the incoming webhook url or the app token for the integration as a parameter.

<bean id="slack" class="org.apache.camel.component.slack.SlackComponent">
    <property name="webhookUrl" value="https://hooks.slack.com/services/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"/>
    <property name="token" value="xoxb-12345678901-1234567890123-xxxxxxxxxxxxxxxxxxxxxxxx"/>
</bean>

For Java you can configure this using Java code.

Example

A CamelContext with Blueprint could be as:

<?xml version="1.0" encoding="UTF-8"?>
<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0" default-activation="lazy">

    <bean id="slack" class="org.apache.camel.component.slack.SlackComponent">
        <property name="webhookUrl" value="https://hooks.slack.com/services/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"/>
    </bean>

    <camelContext xmlns="http://camel.apache.org/schema/blueprint">
        <route>
            <from uri="direct:test"/>
            <to uri="slack:#channel?iconEmoji=:camel:&amp;username=CamelTest"/>
        </route>
    </camelContext>

</blueprint>

Producer

You can now use a token to send a message instead of WebhookUrl

from("direct:test")
    .to("slack:#random?token=RAW(<YOUR_TOKEN>)");

You can now use the Slack API model to create blocks. You can read more about it here https://api.slack.com/block-kit

    public void testSlackAPIModelMessage() {
        Message message = new Message();
        message.setBlocks(Collections.singletonList(SectionBlock
                .builder()
                .text(MarkdownTextObject
                        .builder()
                        .text("*Hello from Camel!*")
                        .build())
                .build()));

        template.sendBody(test, message);
    }

You’ll need to create a Slack app and use it on your workspace.

For token usage, set the 'OAuth Token'.

Add the corresponding (channels:history, chat:write) user token scopes to your app to grant it permission to write messages in the corresponding channel. You’ll also need to invite the Bot or User to the corresponding channel.

For Bot tokens you’ll need the following permissions:

  • channels:history

  • chat:write

For User tokens you’ll need the following permissions:

  • channels:history

  • chat:write

Consumer

You can also use a consumer for messages in a channel

from("slack://general?token=RAW(<YOUR_TOKEN>)&maxResults=1")
    .to("mock:result");

This way you’ll get the last message from general channel. The consumer will track the timestamp of the last message consumed and in the next poll it will consume only newer messages in the channel.

You’ll need to create a Slack app and use it in your workspace.

Use the 'User OAuth Token' as token for the consumer endpoint.

Add the corresponding history (channels:history, groups:history, mpim:history and im:history) and read (channels:read, groups:read, mpim:read and im:read) user token scope to your app to grant it permission to view messages in the corresponding channel.

For Bot tokens you’ll need the following permissions:

  • channels:history

  • groups:history

  • im:history

  • mpim:history

  • channels:read

  • groups:read

  • im:read

  • mpim:read

For User tokens you’ll need the following permissions:

  • channels:history

  • groups:history

  • im:history

  • mpim:history

  • channels:read

  • groups:read

  • im:read

  • mpim:read

The naturalOrder option allows consuming messages from the oldest to the newest. Originally you would get the newest first and consume backward (message 3 ⇒ message 2 ⇒ message 1)

The channel / conversation doesn’t need to be public to read the history and messages. Use the conversationType option to specify the type of the conversation (PUBLIC_CHANNEL,PRIVATE_CHANNEL, MPIM, IM).