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From GitBox <...@apache.org>
Subject [GitHub] [pulsar] Jennifer88huang commented on a change in pull request #7904: Add docs of package Pulsar Functions
Date Thu, 27 Aug 2020 07:44:58 GMT

Jennifer88huang commented on a change in pull request #7904:
URL: https://github.com/apache/pulsar/pull/7904#discussion_r478218036



##########
File path: site2/docs/functions-package.md
##########
@@ -0,0 +1,524 @@
+---
+id: functions-package
+title: Package Pulsar Functions
+sidebar_label: "How-to: Package"
+---
+
+This section provides step-by-step instructions to package Pulsar functions in Java, Python,
and Go. 
+
+> **Tip**
+>
+> - Packaging a window function in Java is the same as [packaging a function in Java](#java)
as below. 
+>
+> - Currently, the window function is not available in Python and Go.
+
+# Prerequisite
+
+Before running a Pulsar function, you need to start up Pulsar.
+
+## Run Pulsar cluster in Docker
+
+This example uses Docker to run a standalone Pulsar.
+
+```bash
+docker run -it \
+    -p 6650:6650 \
+    -p 8080:8080 \
+    -v $PWD/data:/pulsar/data \
+    apachepulsar/pulsar:latest \
+    bin/pulsar standalone
+```
+
+> **Tip**
+>
+> - `$PWD/data` is the local directory. `-v` maps the `/pulsar/data` directory in the
Docker image to the local `$PWD/data` directory.
+>
+> - To check whether the image starts up or not, use the command `docker ps`.
+
+## Run Pulsar cluster in k8s
+
+For how to deploy Pulsar cluster in the k8s environment, please refer to [here](https://pulsar.apache.org/docs/en/helm-overview/).
+
+
+# Java 
+
+This example demonstrates how to package a function in Java.
+
+> **Note**
+>
+> This example assumes that you have [run a standalone Pulsar in Docker](#Run Pulsar cluster
in Docker) successfully.

Review comment:
       1. run a standalone Pulsar in Docker or run Pulsar cluster in Docker?
   2. How about run Pulsar in K8s? Do the following steps work for K8s?

##########
File path: site2/docs/functions-package.md
##########
@@ -0,0 +1,524 @@
+---
+id: functions-package
+title: Package Pulsar Functions
+sidebar_label: "How-to: Package"
+---
+
+This section provides step-by-step instructions to package Pulsar functions in Java, Python,
and Go. 
+
+> **Tip**
+>
+> - Packaging a window function in Java is the same as [packaging a function in Java](#java)
as below. 
+>
+> - Currently, the window function is not available in Python and Go.
+
+# Prerequisite

Review comment:
       Pulsar docs start with heading 2.

##########
File path: site2/docs/functions-package.md
##########
@@ -0,0 +1,524 @@
+---
+id: functions-package
+title: Package Pulsar Functions
+sidebar_label: "How-to: Package"
+---
+
+This section provides step-by-step instructions to package Pulsar functions in Java, Python,
and Go. 
+
+> **Tip**
+>
+> - Packaging a window function in Java is the same as [packaging a function in Java](#java)
as below. 
+>
+> - Currently, the window function is not available in Python and Go.
+
+# Prerequisite
+
+Before running a Pulsar function, you need to start up Pulsar.
+
+## Run Pulsar cluster in Docker
+
+This example uses Docker to run a standalone Pulsar.
+
+```bash
+docker run -it \
+    -p 6650:6650 \
+    -p 8080:8080 \
+    -v $PWD/data:/pulsar/data \
+    apachepulsar/pulsar:latest \
+    bin/pulsar standalone
+```
+
+> **Tip**
+>
+> - `$PWD/data` is the local directory. `-v` maps the `/pulsar/data` directory in the
Docker image to the local `$PWD/data` directory.
+>
+> - To check whether the image starts up or not, use the command `docker ps`.
+
+## Run Pulsar cluster in k8s
+
+For how to deploy Pulsar cluster in the k8s environment, please refer to [here](https://pulsar.apache.org/docs/en/helm-overview/).
+
+
+# Java 
+
+This example demonstrates how to package a function in Java.
+
+> **Note**
+>
+> This example assumes that you have [run a standalone Pulsar in Docker](#Run Pulsar cluster
in Docker) successfully.

Review comment:
       the link is not correct.

##########
File path: site2/docs/functions-package.md
##########
@@ -0,0 +1,524 @@
+---
+id: functions-package
+title: Package Pulsar Functions
+sidebar_label: "How-to: Package"
+---
+
+This section provides step-by-step instructions to package Pulsar functions in Java, Python,
and Go. 
+
+> **Tip**
+>
+> - Packaging a window function in Java is the same as [packaging a function in Java](#java)
as below. 
+>
+> - Currently, the window function is not available in Python and Go.
+
+# Prerequisite
+
+Before running a Pulsar function, you need to start up Pulsar.
+
+## Run Pulsar cluster in Docker
+
+This example uses Docker to run a standalone Pulsar.
+
+```bash
+docker run -it \
+    -p 6650:6650 \
+    -p 8080:8080 \
+    -v $PWD/data:/pulsar/data \
+    apachepulsar/pulsar:latest \
+    bin/pulsar standalone
+```
+
+> **Tip**
+>
+> - `$PWD/data` is the local directory. `-v` maps the `/pulsar/data` directory in the
Docker image to the local `$PWD/data` directory.
+>
+> - To check whether the image starts up or not, use the command `docker ps`.
+
+## Run Pulsar cluster in k8s
+
+For how to deploy Pulsar cluster in the k8s environment, please refer to [here](https://pulsar.apache.org/docs/en/helm-overview/).
+
+
+# Java 
+
+This example demonstrates how to package a function in Java.
+
+> **Note**
+>
+> This example assumes that you have [run a standalone Pulsar in Docker](#Run Pulsar cluster
in Docker) successfully.
+
+
+1. Create a new maven project with a pom file.
+
+    > **Tip**
+    >
+    > `mainClass` is your package name.
+
+    ```text
+    <?xml version="1.0" encoding="UTF-8"?>
+    <project xmlns="http://maven.apache.org/POM/4.0.0"
+            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+            xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+        <modelVersion>4.0.0</modelVersion>
+
+        <groupId>java-function</groupId>
+        <artifactId>java-function</artifactId>
+        <version>1.0-SNAPSHOT</version>
+
+        <dependencies>
+            <dependency>
+                <groupId>org.apache.pulsar</groupId>
+                <artifactId>pulsar-functions-api</artifactId>
+                <version>2.6.0</version>
+            </dependency>
+        </dependencies>
+
+        <build>
+            <plugins>
+                <plugin>
+                    <artifactId>maven-assembly-plugin</artifactId>
+                    <configuration>
+                        <appendAssemblyId>false</appendAssemblyId>
+                        <descriptorRefs>
+                            <descriptorRef>jar-with-dependencies</descriptorRef>
+                        </descriptorRefs>
+                        <archive>
+                        <manifest>
+                            <mainClass>org.example.test.ExclamationFunction</mainClass>
+                        </manifest>
+                    </archive>
+                    </configuration>
+                    <executions>
+                        <execution>
+                            <id>make-assembly</id>
+                            <phase>package</phase>
+                            <goals>
+                                <goal>assembly</goal>
+                            </goals>
+                        </execution>
+                    </executions>
+                </plugin>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <configuration>
+                        <source>8</source>
+                        <target>8</target>
+                    </configuration>
+                </plugin>
+            </plugins>
+        </build>
+
+    </project>
+    ```
+
+2. Write a Java function.
+
+    ```
+    package org.example.test;
+
+    import java.util.function.Function;
+
+    public class ExclamationFunction implements Function<String, String> {
+        @Override
+        public String apply(String s) {
+            return "This is my function!";
+        }
+    }
+    ```
+
+    > **Tip**
+    >
+    > For the package imported, you can use one of the following interfaces:
+    >
+    > - Function interface provided by Java 8: `java.util.function.Function`
+    >
+    > - Pulsar Function interface: `org.apache.pulsar.functions.api.Function`
+    >
+    > The main difference between the two interfaces is that the `org.apache.pulsar.functions.api.Function`
interface provides the context interface. When you write a function and want to interact with
it, you can use context to obtain a wide variety of information and functionality for Pulsar
Functions.
+    > 
+    > **Example** 
+    >
+    > This example uses `org.apache.pulsar.functions.api.Function` interface with context.
+    >
+    > ```
+    > package org.example.functions;
+    >
+    > import org.apache.pulsar.functions.api.Context;
+    > import org.apache.pulsar.functions.api.Function;
+    > 
+    > import java.util.Arrays;
+    >
+    > public class WordCountFunction implements Function<String, Void> {
+    >    // This function is invoked every time a message is published to the input topic
+    >    @Override
+    >    public Void process(String input, Context context) throws Exception {
+    >       Arrays.asList(input.split(" ")).forEach(word -> {
+    >           String counterKey = word.toLowerCase();
+    >           context.incrCounter(counterKey, 1);
+    >        });
+    >       return null;
+    >   }
+    > }
+    > ```
+
+3. Package the Java function.
+
+    ```bash
+    mvn package
+    ```
+
+    After the Java function is packaged, a `target` directory is automatically created. Open
the `target` directory to see if there is a jar package similar to `java-function-1.0-SNAPSHOT.jar`.
+
+
+4.  Run the Java function.
+
+     (1) Copy the packaged jar file to the Pulsar image.
+
+    ```bash
+    docker exec -it [CONTAINER ID] /bin/bash
+    docker cp <path of java-function-1.0-SNAPSHOT.jar>  CONTAINER ID:/pulsar
+    ```
+
+    (2) Run the Java function using the following command.
+
+    ```bash
+    ./bin/pulsar-admin functions localrun \
+    --classname org.example.test.ExclamationFunction \
+    --jar java-function-1.0-SNAPSHOT.jar \
+    --inputs persistent://public/default/my-topic-1 \
+    --output persistent://public/default/test-1 \
+    --tenant public \
+    --namespace default \
+    --name JavaFunction
+    ```
+
+    The following log indicates that the Java function starts up successfully.
+
+    ```text
+    ...
+    07:55:03.724 [main] INFO  org.apache.pulsar.functions.runtime.ProcessRuntime - Started
process successfully
+    ...
+    ```
+
+    > **Tip**
+    >
+    >  - For the descriptions about the parameters (for example, `--classname`, `--jar`,
`--inputs`, and so on), run the command `./bin/pulsar-admin functions` to get more information
or see [here](http://pulsar.apache.org/docs/en/pulsar-admin/#functions).
+    > 
+    > - If you want to start a function in cluster mode, replace `localrun` with `create`
in the command above. The following log indicates that the Java function starts up successfully.
+    >
+    >   ```text
+    >   "Created successfully"
+    >   ```
+
+# Python 
+
+Python Function supports the following three forms:
+
+- One python file
+- ZIP file
+- PIP
+
+## One python file
+
+This example demonstrates how to package a function by **one python file** in Python.
+
+> **Note**
+>
+> This example assumes that you have [run a standalone Pulsar in Docker](#Run Pulsar cluster
in Docker) successfully.

Review comment:
       same questions with the above note.

##########
File path: site2/docs/functions-package.md
##########
@@ -0,0 +1,524 @@
+---
+id: functions-package
+title: Package Pulsar Functions
+sidebar_label: "How-to: Package"
+---
+
+This section provides step-by-step instructions to package Pulsar functions in Java, Python,
and Go. 
+
+> **Tip**
+>
+> - Packaging a window function in Java is the same as [packaging a function in Java](#java)
as below. 
+>
+> - Currently, the window function is not available in Python and Go.
+
+# Prerequisite
+
+Before running a Pulsar function, you need to start up Pulsar.
+
+## Run Pulsar cluster in Docker
+
+This example uses Docker to run a standalone Pulsar.
+
+```bash
+docker run -it \
+    -p 6650:6650 \
+    -p 8080:8080 \
+    -v $PWD/data:/pulsar/data \
+    apachepulsar/pulsar:latest \
+    bin/pulsar standalone
+```
+
+> **Tip**
+>
+> - `$PWD/data` is the local directory. `-v` maps the `/pulsar/data` directory in the
Docker image to the local `$PWD/data` directory.
+>
+> - To check whether the image starts up or not, use the command `docker ps`.
+
+## Run Pulsar cluster in k8s
+
+For how to deploy Pulsar cluster in the k8s environment, please refer to [here](https://pulsar.apache.org/docs/en/helm-overview/).

Review comment:
       remove "please".
   For details, refer to https://developers.google.com/style/tone#politeness-and-use-of-please

##########
File path: site2/docs/functions-package.md
##########
@@ -0,0 +1,524 @@
+---
+id: functions-package
+title: Package Pulsar Functions
+sidebar_label: "How-to: Package"
+---
+
+This section provides step-by-step instructions to package Pulsar functions in Java, Python,
and Go. 
+
+> **Tip**
+>
+> - Packaging a window function in Java is the same as [packaging a function in Java](#java)
as below. 
+>
+> - Currently, the window function is not available in Python and Go.
+
+# Prerequisite
+
+Before running a Pulsar function, you need to start up Pulsar.

Review comment:
       start  up --> start
   Check all similar cases in this md file.

##########
File path: site2/docs/functions-package.md
##########
@@ -0,0 +1,524 @@
+---
+id: functions-package
+title: Package Pulsar Functions
+sidebar_label: "How-to: Package"
+---
+
+This section provides step-by-step instructions to package Pulsar functions in Java, Python,
and Go. 
+
+> **Tip**
+>
+> - Packaging a window function in Java is the same as [packaging a function in Java](#java)
as below. 
+>
+> - Currently, the window function is not available in Python and Go.
+
+# Prerequisite
+
+Before running a Pulsar function, you need to start up Pulsar.
+
+## Run Pulsar cluster in Docker
+
+This example uses Docker to run a standalone Pulsar.
+
+```bash
+docker run -it \
+    -p 6650:6650 \
+    -p 8080:8080 \
+    -v $PWD/data:/pulsar/data \
+    apachepulsar/pulsar:latest \
+    bin/pulsar standalone
+```
+
+> **Tip**
+>
+> - `$PWD/data` is the local directory. `-v` maps the `/pulsar/data` directory in the
Docker image to the local `$PWD/data` directory.
+>
+> - To check whether the image starts up or not, use the command `docker ps`.
+
+## Run Pulsar cluster in k8s
+
+For how to deploy Pulsar cluster in the k8s environment, please refer to [here](https://pulsar.apache.org/docs/en/helm-overview/).
+
+
+# Java 
+
+This example demonstrates how to package a function in Java.
+
+> **Note**
+>
+> This example assumes that you have [run a standalone Pulsar in Docker](#Run Pulsar cluster
in Docker) successfully.
+
+
+1. Create a new maven project with a pom file.
+
+    > **Tip**
+    >
+    > `mainClass` is your package name.
+
+    ```text
+    <?xml version="1.0" encoding="UTF-8"?>
+    <project xmlns="http://maven.apache.org/POM/4.0.0"
+            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+            xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+        <modelVersion>4.0.0</modelVersion>
+
+        <groupId>java-function</groupId>
+        <artifactId>java-function</artifactId>
+        <version>1.0-SNAPSHOT</version>
+
+        <dependencies>
+            <dependency>
+                <groupId>org.apache.pulsar</groupId>
+                <artifactId>pulsar-functions-api</artifactId>
+                <version>2.6.0</version>
+            </dependency>
+        </dependencies>
+
+        <build>
+            <plugins>
+                <plugin>
+                    <artifactId>maven-assembly-plugin</artifactId>
+                    <configuration>
+                        <appendAssemblyId>false</appendAssemblyId>
+                        <descriptorRefs>
+                            <descriptorRef>jar-with-dependencies</descriptorRef>
+                        </descriptorRefs>
+                        <archive>
+                        <manifest>
+                            <mainClass>org.example.test.ExclamationFunction</mainClass>
+                        </manifest>
+                    </archive>
+                    </configuration>
+                    <executions>
+                        <execution>
+                            <id>make-assembly</id>
+                            <phase>package</phase>
+                            <goals>
+                                <goal>assembly</goal>
+                            </goals>
+                        </execution>
+                    </executions>
+                </plugin>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <configuration>
+                        <source>8</source>
+                        <target>8</target>
+                    </configuration>
+                </plugin>
+            </plugins>
+        </build>
+
+    </project>
+    ```
+
+2. Write a Java function.
+
+    ```
+    package org.example.test;
+
+    import java.util.function.Function;
+
+    public class ExclamationFunction implements Function<String, String> {
+        @Override
+        public String apply(String s) {
+            return "This is my function!";
+        }
+    }
+    ```
+
+    > **Tip**
+    >
+    > For the package imported, you can use one of the following interfaces:
+    >
+    > - Function interface provided by Java 8: `java.util.function.Function`
+    >
+    > - Pulsar Function interface: `org.apache.pulsar.functions.api.Function`
+    >
+    > The main difference between the two interfaces is that the `org.apache.pulsar.functions.api.Function`
interface provides the context interface. When you write a function and want to interact with
it, you can use context to obtain a wide variety of information and functionality for Pulsar
Functions.
+    > 
+    > **Example** 
+    >
+    > This example uses `org.apache.pulsar.functions.api.Function` interface with context.
+    >
+    > ```
+    > package org.example.functions;
+    >
+    > import org.apache.pulsar.functions.api.Context;
+    > import org.apache.pulsar.functions.api.Function;
+    > 
+    > import java.util.Arrays;
+    >
+    > public class WordCountFunction implements Function<String, Void> {
+    >    // This function is invoked every time a message is published to the input topic
+    >    @Override
+    >    public Void process(String input, Context context) throws Exception {
+    >       Arrays.asList(input.split(" ")).forEach(word -> {
+    >           String counterKey = word.toLowerCase();
+    >           context.incrCounter(counterKey, 1);
+    >        });
+    >       return null;
+    >   }
+    > }
+    > ```
+
+3. Package the Java function.
+
+    ```bash
+    mvn package
+    ```
+
+    After the Java function is packaged, a `target` directory is automatically created. Open
the `target` directory to see if there is a jar package similar to `java-function-1.0-SNAPSHOT.jar`.
+
+
+4.  Run the Java function.
+
+     (1) Copy the packaged jar file to the Pulsar image.
+
+    ```bash
+    docker exec -it [CONTAINER ID] /bin/bash
+    docker cp <path of java-function-1.0-SNAPSHOT.jar>  CONTAINER ID:/pulsar
+    ```
+
+    (2) Run the Java function using the following command.
+
+    ```bash
+    ./bin/pulsar-admin functions localrun \
+    --classname org.example.test.ExclamationFunction \
+    --jar java-function-1.0-SNAPSHOT.jar \
+    --inputs persistent://public/default/my-topic-1 \
+    --output persistent://public/default/test-1 \
+    --tenant public \
+    --namespace default \
+    --name JavaFunction
+    ```
+
+    The following log indicates that the Java function starts up successfully.
+
+    ```text
+    ...
+    07:55:03.724 [main] INFO  org.apache.pulsar.functions.runtime.ProcessRuntime - Started
process successfully
+    ...
+    ```
+
+    > **Tip**
+    >
+    >  - For the descriptions about the parameters (for example, `--classname`, `--jar`,
`--inputs`, and so on), run the command `./bin/pulsar-admin functions` to get more information
or see [here](http://pulsar.apache.org/docs/en/pulsar-admin/#functions).

Review comment:
       descriptions --> description

##########
File path: site2/docs/functions-package.md
##########
@@ -0,0 +1,524 @@
+---
+id: functions-package
+title: Package Pulsar Functions
+sidebar_label: "How-to: Package"
+---
+
+This section provides step-by-step instructions to package Pulsar functions in Java, Python,
and Go. 
+
+> **Tip**
+>
+> - Packaging a window function in Java is the same as [packaging a function in Java](#java)
as below. 
+>
+> - Currently, the window function is not available in Python and Go.
+
+# Prerequisite
+
+Before running a Pulsar function, you need to start up Pulsar.
+
+## Run Pulsar cluster in Docker
+
+This example uses Docker to run a standalone Pulsar.
+
+```bash
+docker run -it \
+    -p 6650:6650 \
+    -p 8080:8080 \
+    -v $PWD/data:/pulsar/data \
+    apachepulsar/pulsar:latest \
+    bin/pulsar standalone
+```
+
+> **Tip**
+>
+> - `$PWD/data` is the local directory. `-v` maps the `/pulsar/data` directory in the
Docker image to the local `$PWD/data` directory.
+>
+> - To check whether the image starts up or not, use the command `docker ps`.
+
+## Run Pulsar cluster in k8s
+
+For how to deploy Pulsar cluster in the k8s environment, please refer to [here](https://pulsar.apache.org/docs/en/helm-overview/).
+
+
+# Java 
+
+This example demonstrates how to package a function in Java.
+
+> **Note**
+>
+> This example assumes that you have [run a standalone Pulsar in Docker](#Run Pulsar cluster
in Docker) successfully.
+
+
+1. Create a new maven project with a pom file.
+
+    > **Tip**
+    >
+    > `mainClass` is your package name.
+
+    ```text
+    <?xml version="1.0" encoding="UTF-8"?>
+    <project xmlns="http://maven.apache.org/POM/4.0.0"
+            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+            xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+        <modelVersion>4.0.0</modelVersion>
+
+        <groupId>java-function</groupId>
+        <artifactId>java-function</artifactId>
+        <version>1.0-SNAPSHOT</version>
+
+        <dependencies>
+            <dependency>
+                <groupId>org.apache.pulsar</groupId>
+                <artifactId>pulsar-functions-api</artifactId>
+                <version>2.6.0</version>
+            </dependency>
+        </dependencies>
+
+        <build>
+            <plugins>
+                <plugin>
+                    <artifactId>maven-assembly-plugin</artifactId>
+                    <configuration>
+                        <appendAssemblyId>false</appendAssemblyId>
+                        <descriptorRefs>
+                            <descriptorRef>jar-with-dependencies</descriptorRef>
+                        </descriptorRefs>
+                        <archive>
+                        <manifest>
+                            <mainClass>org.example.test.ExclamationFunction</mainClass>
+                        </manifest>
+                    </archive>
+                    </configuration>
+                    <executions>
+                        <execution>
+                            <id>make-assembly</id>
+                            <phase>package</phase>
+                            <goals>
+                                <goal>assembly</goal>
+                            </goals>
+                        </execution>
+                    </executions>
+                </plugin>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <configuration>
+                        <source>8</source>
+                        <target>8</target>
+                    </configuration>
+                </plugin>
+            </plugins>
+        </build>
+
+    </project>
+    ```
+
+2. Write a Java function.
+
+    ```
+    package org.example.test;
+
+    import java.util.function.Function;
+
+    public class ExclamationFunction implements Function<String, String> {
+        @Override
+        public String apply(String s) {
+            return "This is my function!";
+        }
+    }
+    ```
+
+    > **Tip**
+    >
+    > For the package imported, you can use one of the following interfaces:
+    >
+    > - Function interface provided by Java 8: `java.util.function.Function`
+    >
+    > - Pulsar Function interface: `org.apache.pulsar.functions.api.Function`
+    >
+    > The main difference between the two interfaces is that the `org.apache.pulsar.functions.api.Function`
interface provides the context interface. When you write a function and want to interact with
it, you can use context to obtain a wide variety of information and functionality for Pulsar
Functions.
+    > 
+    > **Example** 
+    >
+    > This example uses `org.apache.pulsar.functions.api.Function` interface with context.
+    >
+    > ```
+    > package org.example.functions;
+    >
+    > import org.apache.pulsar.functions.api.Context;
+    > import org.apache.pulsar.functions.api.Function;
+    > 
+    > import java.util.Arrays;
+    >
+    > public class WordCountFunction implements Function<String, Void> {
+    >    // This function is invoked every time a message is published to the input topic
+    >    @Override
+    >    public Void process(String input, Context context) throws Exception {
+    >       Arrays.asList(input.split(" ")).forEach(word -> {
+    >           String counterKey = word.toLowerCase();
+    >           context.incrCounter(counterKey, 1);
+    >        });
+    >       return null;
+    >   }
+    > }
+    > ```
+
+3. Package the Java function.
+
+    ```bash
+    mvn package
+    ```
+
+    After the Java function is packaged, a `target` directory is automatically created. Open
the `target` directory to see if there is a jar package similar to `java-function-1.0-SNAPSHOT.jar`.
+
+
+4.  Run the Java function.
+
+     (1) Copy the packaged jar file to the Pulsar image.
+
+    ```bash
+    docker exec -it [CONTAINER ID] /bin/bash
+    docker cp <path of java-function-1.0-SNAPSHOT.jar>  CONTAINER ID:/pulsar
+    ```
+
+    (2) Run the Java function using the following command.
+
+    ```bash
+    ./bin/pulsar-admin functions localrun \
+    --classname org.example.test.ExclamationFunction \
+    --jar java-function-1.0-SNAPSHOT.jar \
+    --inputs persistent://public/default/my-topic-1 \
+    --output persistent://public/default/test-1 \
+    --tenant public \
+    --namespace default \
+    --name JavaFunction
+    ```
+
+    The following log indicates that the Java function starts up successfully.
+
+    ```text
+    ...
+    07:55:03.724 [main] INFO  org.apache.pulsar.functions.runtime.ProcessRuntime - Started
process successfully
+    ...
+    ```
+
+    > **Tip**
+    >
+    >  - For the descriptions about the parameters (for example, `--classname`, `--jar`,
`--inputs`, and so on), run the command `./bin/pulsar-admin functions` to get more information
or see [here](http://pulsar.apache.org/docs/en/pulsar-admin/#functions).
+    > 
+    > - If you want to start a function in cluster mode, replace `localrun` with `create`
in the command above. The following log indicates that the Java function starts up successfully.
+    >
+    >   ```text
+    >   "Created successfully"
+    >   ```
+
+# Python 
+
+Python Function supports the following three forms:
+
+- One python file
+- ZIP file
+- PIP
+
+## One python file
+
+This example demonstrates how to package a function by **one python file** in Python.
+
+> **Note**
+>
+> This example assumes that you have [run a standalone Pulsar in Docker](#Run Pulsar cluster
in Docker) successfully.
+
+1. Write a Python function.
+
+    ```
+    from pulsar import Function //  import the Function module from Pulsar
+
+    # The classic ExclamationFunction that appends an exclamation at the end
+    # of the input
+    class ExclamationFunction(Function):
+      def __init__(self):
+        pass
+
+      def process(self, input, context):
+        return input + '!'
+    ```
+
+    In this example, when you write a Python function, you need to inherit the Function class
and implement the `process()` method.
+
+    `process()` mainly has two parameters: 
+
+    - `input` represents your input.
+  
+    - `context` represents an interface exposed by the Pulsar Function. You can get the attributes
in the Python function based on the provided context object.
+
+2. Install a Python client.
+
+    The implementation of a Python function depends on the Python client, so before deploying
a Python function, you need to install the corresponding version of the Python client. 
+
+    ```bash
+    pip install python-client==2.6.0
+    ```
+
+3. Run the Python Function.
+
+    (1) Copy the Python function file to the Pulsar image.
+
+    ```bash
+    docker exec -it [CONTAINER ID] /bin/bash
+    docker cp <path of Python function file>  CONTAINER ID:/pulsar
+    ```
+
+    (2) Run the Python function using the following command.
+
+    ```bash
+    ./bin/pulsar-admin functions localrun \
+    --classname org.example.test.ExclamationFunction \
+    --py <path of Python Function file> \
+    --inputs persistent://public/default/my-topic-1 \
+    --output persistent://public/default/test-1 \
+    --tenant public \
+    --namespace default \
+    --name PythonFunction
+    ```
+
+    The following log indicates that the Python function starts up successfully.
+
+    ```text
+    ...
+    07:55:03.724 [main] INFO  org.apache.pulsar.functions.runtime.ProcessRuntime - Started
process successfully
+    ...
+    ```
+
+    > **Tip**
+    >
+    >  - For the descriptions about the parameters (for example, `--classname`, `--py`,
`--inputs`, and so on), run the command `./bin/pulsar-admin functions` to get more information
or see [here](http://pulsar.apache.org/docs/en/pulsar-admin/#functions).
+    > 
+    > - If you want to start a function in cluster mode, replace `localrun` with `create`
in the command above. The following log indicates that the Python function starts up successfully.
+    >
+    >   ```text
+    >   "Created successfully"
+    >   ```
+
+## ZIP file
+
+This example demonstrates how to package a function by **ZIP file** in Python.
+
+> **Note**
+>
+> This example assumes that you have [run a standalone Pulsar in Docker](#Run Pulsar cluster
in Docker) successfully.

Review comment:
       the link is not correct, check all similar cases.




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