slack/slack-source/README.adoc

# Camel-Kafka-connector Slack Source

This is an example for Camel-Kafka-connector Slack Source 

## Standalone

### What is needed

- A Slack app
- A Slack channel

### Setting up Slack

You'll need a workspace and a channel.

In your Slack settings, create an app.

Add the following permissions to your Bot Token scopes:
* channels:history
* channels:read

Install the app on your workspace and select the channel you want to consume from. 

Use the Bot User OAuth Access Token as token for this example.

### Running Kafka

```
$KAFKA_HOME/bin/zookeeper-server-start.sh config/zookeeper.properties
$KAFKA_HOME/bin/kafka-server-start.sh config/server.properties
$KAFKA_HOME/bin/kafka-topics.sh --create --bootstrap-server localhost:9092 --replication-factor 1 --partitions 1 --topic mytopic
```

### Setting up the needed bits and running the example

You'll need to setup the plugin.path property in your kafka

Open the `$KAFKA_HOME/config/connect-standalone.properties`

and set the `plugin.path` property to your choosen location

You'll need to build your connector starting from an archetype:

```
> mvn archetype:generate  -DarchetypeGroupId=org.apache.camel.kafkaconnector.archetypes  -DarchetypeArtifactId=camel-kafka-connector-extensible-archetype  -DarchetypeVersion=0.5.0
[INFO] Scanning for projects...
[INFO] 
[INFO] ------------------< org.apache.maven:standalone-pom >-------------------
[INFO] Building Maven Stub Project (No POM) 1
[INFO] --------------------------------[ pom ]---------------------------------
[INFO] 
[INFO] >>> maven-archetype-plugin:3.1.2:generate (default-cli) > generate-sources @ standalone-pom >>>
[INFO] 
[INFO] <<< maven-archetype-plugin:3.1.2:generate (default-cli) < generate-sources @ standalone-pom <<<
[INFO] 
[INFO] 
[INFO] --- maven-archetype-plugin:3.1.2:generate (default-cli) @ standalone-pom ---
[INFO] Generating project in Interactive mode
[INFO] Archetype repository not defined. Using the one from [org.apache.camel.kafkaconnector.archetypes:camel-kafka-connector-extensible-archetype:0.4.0] found in catalog remote
Define value for property 'groupId': org.apache.camel.kafkaconnector
Define value for property 'artifactId': slack-extended
Define value for property 'version' 1.0-SNAPSHOT: : 0.5.0
Define value for property 'package' org.apache.camel.kafkaconnector: : 
Define value for property 'camel-kafka-connector-name': camel-slack-kafka-connector
[INFO] Using property: camel-kafka-connector-version = 0.5.0
Confirm properties configuration:
groupId: org.apache.camel.kafkaconnector
artifactId: slack-extended
version: 0.5.0
package: org.apache.camel.kafkaconnector
camel-kafka-connector-name: camel-slack-kafka-connector
camel-kafka-connector-version: 0.5.0
 Y: : y
[INFO] ----------------------------------------------------------------------------
[INFO] Using following parameters for creating project from Archetype: camel-kafka-connector-extensible-archetype:0.5.0
[INFO] ----------------------------------------------------------------------------
[INFO] Parameter: groupId, Value: org.apache.camel.kafkaconnector
[INFO] Parameter: artifactId, Value: slack-extended
[INFO] Parameter: version, Value: 0.5.0
[INFO] Parameter: package, Value: org.apache.camel.kafkaconnector
[INFO] Parameter: packageInPathFormat, Value: org/apache/camel/kafkaconnector
[INFO] Parameter: package, Value: org.apache.camel.kafkaconnector
[INFO] Parameter: version, Value: 0.5.0
[INFO] Parameter: groupId, Value: org.apache.camel.kafkaconnector
[INFO] Parameter: camel-kafka-connector-name, Value: camel-slack-kafka-connector
[INFO] Parameter: camel-kafka-connector-version, Value: 0.5.0
[INFO] Parameter: artifactId, Value: slack-extended
[INFO] Project created from Archetype in dir: /home/oscerd/playground/slack-extended
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  39.295 s
[INFO] Finished at: 2020-10-13T09:16:51+02:00
[INFO] ------------------------------------------------------------------------
> cd /home/workspace/miscellanea/slack-extended
```

and add the following class in the main package

```
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.camel.kafkaconnector.slack.source;

import java.util.Map;

import org.apache.camel.component.slack.helper.SlackMessage;
import org.apache.camel.kafkaconnector.utils.SchemaHelper;
import org.apache.kafka.common.config.ConfigDef;
import org.apache.kafka.connect.connector.ConnectRecord;
import org.apache.kafka.connect.transforms.Transformation;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class SlackTransformer <R extends ConnectRecord<R>> implements Transformation<R> {
    public static final String FIELD_KEY_CONFIG = "key";
    public static final ConfigDef CONFIG_DEF = new ConfigDef()
            .define(FIELD_KEY_CONFIG, ConfigDef.Type.STRING, null, ConfigDef.Importance.MEDIUM,
                    "Transforms String-based content from Kafka into a map");

    private static final Logger LOG = LoggerFactory.getLogger(SlackTransformer.class);

    @Override
    public R apply(R r) {
        Object value = r.value();

        if (r.value() instanceof SlackMessage) {
            LOG.debug("Converting record from SlackMessage to text");
            SlackMessage message = (SlackMessage) r.value();

            LOG.debug("Received text: {}", message.getText());

            return r.newRecord(r.topic(), r.kafkaPartition(), null, r.key(),
                    SchemaHelper.buildSchemaBuilderForType(message.getText()), message.getText(), r.timestamp());

        } else {
            LOG.debug("Unexpected message type: {}", r.value().getClass());

            return r;
        }
    }

    @Override
    public ConfigDef config() {
        return CONFIG_DEF;
    }

    @Override
    public void close() {

    }

    @Override
    public void configure(Map<String, ?> map) {

    }
}
```

Now we need to build the connector:

```
> mvn clean package
```

In this example we'll use `/home/oscerd/connectors/` as plugin.path, but we'll need the generated zip from the previois build

```
> cd /home/oscerd/connectors/
> cp /home/workspace/miscellanea/slack-extended/target/slack-extended-0.5.0-package.zip .
> unzip slack-extended-0.5.0-package.zip
```

Now it's time to setup the connectors

Open the Slack source configuration file

```
name=CamelSlackSourceConnector
connector.class=org.apache.camel.kafkaconnector.slack.CamelSlackSourceConnector
key.converter=org.apache.kafka.connect.storage.StringConverter
transforms=SlackTransformer
transforms.SlackTransformer.type=org.apache.camel.kafkaconnector.SlackTransformer

topics=mytopic

camel.source.path.channel=general
camel.source.endpoint.token=<the token created for your Bot>
```

Now you can run the example

```
$KAFKA_HOME/bin/connect-standalone.sh $KAFKA_HOME/config/connect-standalone.properties config/CamelSlackSourceConnector.properties
```

Add messages to your channel for example "Hello"

In another terminal, using kafkacat, you should be able to see the headers.

```
>  kafkacat -b localhost:9092 -t mytopic -f 'Topic %t[%p], offset: %o, key: %k, payload: %s \n'
Topic test301[0], offset: 22, key: , payload: {"schema":{"type":"string","optional":false},"payload":"Hello"} 
```

## Openshift

### What is needed

- A Slack App
- A Slack channel
- An Openshift instance

### Running Kafka using Strimzi Operator

First we install the Strimzi operator and use it to deploy the Kafka broker and Kafka Connect into our OpenShift project.
We need to create security objects as part of installation so it is necessary to switch to admin user.
If you use Minishift, you can do it with the following command:

[source,bash,options="nowrap"]
----
oc login -u system:admin
----

We will use OpenShift project `myproject`.
If it doesn't exist yet, you can create it using following command:

[source,bash,options="nowrap"]
----
oc new-project myproject
----

If the project already exists, you can switch to it with:

[source,bash,options="nowrap"]
----
oc project myproject
----

We can now install the Strimzi operator into this project:

[source,bash,options="nowrap",subs="attributes"]
----
oc apply -f https://github.com/strimzi/strimzi-kafka-operator/releases/download/0.19.0/strimzi-cluster-operator-0.19.0.yaml
----

Next we will deploy a Kafka broker cluster and a Kafka Connect cluster and then create a Kafka Connect image with the Debezium connectors installed:

[source,bash,options="nowrap",subs="attributes"]
----
# Deploy a single node Kafka broker
oc apply -f https://github.com/strimzi/strimzi-kafka-operator/raw/0.19.0/examples/kafka/kafka-persistent-single.yaml

# Deploy a single instance of Kafka Connect with no plug-in installed
oc apply -f https://github.com/strimzi/strimzi-kafka-operator/raw/0.19.0/examples/connect/kafka-connect-s2i-single-node-kafka.yaml
----

Optionally enable the possibility to instantiate Kafka Connectors through specific custom resource:
[source,bash,options="nowrap"]
----
oc annotate kafkaconnects2is my-connect-cluster strimzi.io/use-connector-resources=true
----

### Add Camel Kafka connector binaries

Strimzi uses `Source2Image` builds to allow users to add their own connectors to the existing Strimzi Docker images.
We now need to build the connectors and add them to the image,
if you have built the whole project (`mvn clean package`) decompress the connectors you need in a folder (i.e. like `my-connectors/`)
so that each one is in its own subfolder
(alternatively you can download the latest officially released and packaged connectors from maven):

In this case we need to extend an existing connector and add a Transform, so we need to leverage the archetype

```
> mvn archetype:generate  -DarchetypeGroupId=org.apache.camel.kafkaconnector.archetypes  -DarchetypeArtifactId=camel-kafka-connector-extensible-archetype  -DarchetypeVersion=0.5.0
[INFO] Scanning for projects...
[INFO] 
[INFO] ------------------< org.apache.maven:standalone-pom >-------------------
[INFO] Building Maven Stub Project (No POM) 1
[INFO] --------------------------------[ pom ]---------------------------------
[INFO] 
[INFO] >>> maven-archetype-plugin:3.1.2:generate (default-cli) > generate-sources @ standalone-pom >>>
[INFO] 
[INFO] <<< maven-archetype-plugin:3.1.2:generate (default-cli) < generate-sources @ standalone-pom <<<
[INFO] 
[INFO] 
[INFO] --- maven-archetype-plugin:3.1.2:generate (default-cli) @ standalone-pom ---
[INFO] Generating project in Interactive mode
[INFO] Archetype repository not defined. Using the one from [org.apache.camel.kafkaconnector.archetypes:camel-kafka-connector-extensible-archetype:0.4.0] found in catalog remote
Define value for property 'groupId': org.apache.camel.kafkaconnector
Define value for property 'artifactId': slack-extended
Define value for property 'version' 1.0-SNAPSHOT: : 0.5.0
Define value for property 'package' org.apache.camel.kafkaconnector: : 
Define value for property 'camel-kafka-connector-name': camel-slack-kafka-connector
[INFO] Using property: camel-kafka-connector-version = 0.5.0
Confirm properties configuration:
groupId: org.apache.camel.kafkaconnector
artifactId: slack-extended
version: 0.5.0
package: org.apache.camel.kafkaconnector
camel-kafka-connector-name: camel-slack-kafka-connector
camel-kafka-connector-version: 0.5.0
 Y: : y
[INFO] ----------------------------------------------------------------------------
[INFO] Using following parameters for creating project from Archetype: camel-kafka-connector-extensible-archetype:0.5.0
[INFO] ----------------------------------------------------------------------------
[INFO] Parameter: groupId, Value: org.apache.camel.kafkaconnector
[INFO] Parameter: artifactId, Value: slack-extended
[INFO] Parameter: version, Value: 0.5.0
[INFO] Parameter: package, Value: org.apache.camel.kafkaconnector
[INFO] Parameter: packageInPathFormat, Value: org/apache/camel/kafkaconnector
[INFO] Parameter: package, Value: org.apache.camel.kafkaconnector
[INFO] Parameter: version, Value: 0.5.0
[INFO] Parameter: groupId, Value: org.apache.camel.kafkaconnector
[INFO] Parameter: camel-kafka-connector-name, Value: camel-slack-kafka-connector
[INFO] Parameter: camel-kafka-connector-version, Value: 0.5.0
[INFO] Parameter: artifactId, Value: slack-extended
[INFO] Project created from Archetype in dir: /home/oscerd/playground/slack-extended
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  39.295 s
[INFO] Finished at: 2020-10-13T09:16:51+02:00
[INFO] ------------------------------------------------------------------------
> cd /home/workspace/miscellanea/slack-extended
```
and add the following class in the main package

```
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.camel.kafkaconnector.slack.source;

import java.util.Map;

import org.apache.camel.component.slack.helper.SlackMessage;
import org.apache.camel.kafkaconnector.utils.SchemaHelper;
import org.apache.kafka.common.config.ConfigDef;
import org.apache.kafka.connect.connector.ConnectRecord;
import org.apache.kafka.connect.transforms.Transformation;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class SlackTransformer <R extends ConnectRecord<R>> implements Transformation<R> {
    public static final String FIELD_KEY_CONFIG = "key";
    public static final ConfigDef CONFIG_DEF = new ConfigDef()
            .define(FIELD_KEY_CONFIG, ConfigDef.Type.STRING, null, ConfigDef.Importance.MEDIUM,
                    "Transforms String-based content from Kafka into a map");

    private static final Logger LOG = LoggerFactory.getLogger(SlackTransformer.class);

    @Override
    public R apply(R r) {
        Object value = r.value();

        if (r.value() instanceof SlackMessage) {
            LOG.debug("Converting record from SlackMessage to text");
            SlackMessage message = (SlackMessage) r.value();

            LOG.debug("Received text: {}", message.getText());

            return r.newRecord(r.topic(), r.kafkaPartition(), null, r.key(),
                    SchemaHelper.buildSchemaBuilderForType(message.getText()), message.getText(), r.timestamp());

        } else {
            LOG.debug("Unexpected message type: {}", r.value().getClass());

            return r;
        }
    }

    @Override
    public ConfigDef config() {
        return CONFIG_DEF;
    }

    @Override
    public void close() {

    }

    @Override
    public void configure(Map<String, ?> map) {

    }
}
```

Now we need to build the connector:

```
> mvn clean package
```
And move the zip package in targe to my-connectors folder and unzipped it.

Now we can start the build 

[source,bash,options="nowrap"]
----
oc start-build my-connect-cluster-connect --from-dir=./my-connectors/ --follow
----

We should now wait for the rollout of the new image to finish and the replica set with the new connector to become ready.
Once it is done, we can check that the connectors are available in our Kafka Connect cluster.
Strimzi is running Kafka Connect in a distributed mode.

To check the available connector plugins, you can run the following command:

[source,bash,options="nowrap"]
----
oc exec -i `oc get pods --field-selector status.phase=Running -l strimzi.io/name=my-connect-cluster-connect -o=jsonpath='{.items[0].metadata.name}'` -- curl -s http://my-connect-cluster-connect-api:8083/connector-plugins
----

You should see something like this:

[source,json,options="nowrap"]
----
[{"class":"org.apache.camel.kafkaconnector.CamelSinkConnector","type":"sink","version":"0.5.0"},{"class":"org.apache.camel.kafkaconnector.CamelSourceConnector","type":"source","version":"0.5.0"},{"class":"org.apache.camel.kafkaconnector.slack.CamelSlackSinkConnector","type":"sink","version":"0.5.0"},{"class":"org.apache.camel.kafkaconnector.slack.CamelSlackSourceConnector","type":"source","version":"0.5.0"},{"class":"org.apache.kafka.connect.file.FileStreamSinkConnector","type":"sink","version":"2.5.0"},{"class":"org.apache.kafka.connect.file.FileStreamSourceConnector","type":"source","version":"2.5.0"},{"class":"org.apache.kafka.connect.mirror.MirrorCheckpointConnector","type":"source","version":"1"},{"class":"org.apache.kafka.connect.mirror.MirrorHeartbeatConnector","type":"source","version":"1"},{"class":"org.apache.kafka.connect.mirror.MirrorSourceConnector","type":"source","version":"1"}]
----

### Set the Bot Token as secret (optional)

You can also set the aws creds option as secret, you'll need to edit the file config/aws2-s3-cred.properties with the correct credentials and then execute the following command

[source,bash,options="nowrap"]
----
oc create secret generic slack-token --from-file=config/openshift/slack-token.properties
----

Now we need to edit KafkaConnectS2I custom resource to reference the secret. For example:

[source,bash,options="nowrap"]
----
spec:
  # ...
  config:
    config.providers: file
    config.providers.file.class: org.apache.kafka.common.config.provider.FileConfigProvider
  #...
  externalConfiguration:
    volumes:
      - name: slack-token
        secret:
          secretName: slack-token
----

In this way the secret slack-token will be mounted as volume with path /opt/kafka/external-configuration/slack-token/

### Create connector instance

Now we can create some instance of the Slack source connector:

[source,bash,options="nowrap"]
----
oc exec -i `oc get pods --field-selector status.phase=Running -l strimzi.io/name=my-connect-cluster-connect -o=jsonpath='{.items[0].metadata.name}'` -- curl -X POST \
    -H "Accept:application/json" \
    -H "Content-Type:application/json" \
    http://my-connect-cluster-connect-api:8083/connectors -d @- <<'EOF'
{
  "name": "slack-source-connector",
  "config": {
    "connector.class": "org.apache.camel.kafkaconnector.slack.CamelSlackSourceConnector",
    "tasks.max": "1",
    "key.converter": "org.apache.kafka.connect.storage.StringConverter",
    "transforms": "SlackTransformer",
    "transforms.SlackTransformer.type": "org.apache.camel.kafkaconnector.SlackTransformer",
    "topics": "slack-topic",
    "camel.source.path.channel": "general",
    "camel.source.endpoint.token": "<token>"
  }
}
EOF
----

Altenatively, if have enabled `use-connector-resources`, you can create the connector instance by creating a specific custom resource:

[source,bash,options="nowrap"]
----
oc apply -f - << EOF
apiVersion: kafka.strimzi.io/v1alpha1
kind: KafkaConnector
metadata:
  name: slack-source-connector
  namespace: myproject
  labels:
    strimzi.io/cluster: my-connect-cluster
spec:
  class: org.apache.camel.kafkaconnector.slack.CamelSlackSourceConnector
  tasksMax: 1
  config:
    key.converter: org.apache.kafka.connect.storage.StringConverter
    transforms: SlackTransformer
    transforms.SlackTransformer.type: org.apache.camel.kafkaconnector.SlackTransformer
    topics: slack-topic
    camel.source.path.channel: general
    camel.source.endpoint.token: token
EOF
----

If you followed the optional step for secret webhook you can run the following command:

[source,bash,options="nowrap"]
----
oc apply -f config/openshift/slack-source.yaml
----

Add messages to your channel for example "Hello"

Using kafkacat, you should be able to see the headers.

```
>  kafkacat -b localhost:9092 -t mytopic -f 'Topic %t[%p], offset: %o, key: %k, payload: %s \n'
Topic test301[0], offset: 22, key: , payload: {"schema":{"type":"string","optional":false},"payload":"Hello"} 
```