diff --git a/multi/multi__standalone_streaming_applications.html b/multi/multi__standalone_streaming_applications.html index cfc31249b..7936a9247 100644 --- a/multi/multi__standalone_streaming_applications.html +++ b/multi/multi__standalone_streaming_applications.html @@ -1,3 +1,4 @@ - 6. Standalone Streaming Applications
6. Standalone Streaming Applications
Prev   Next

6. Standalone Streaming Applications

To send or receive messages from a broker (such as RabbitMQ or Kafka) you can use the spring-cloud-function-stream adapter. Add the adapter to your classpath along with the appropriate binder from Spring Cloud Stream. The adapter will bind to the message broker as a Processor (input and output streams) unless the user explicitly disables one or the other using spring.cloud.function.stream.{source,sink}.enabled=false.

An incoming message is routed to a function (or consumer). If there is only one, then the choice is obvious. If there are multiple functions that can accept an incoming message, the message is inspected to see if there is a stream_routekey header containing the name of a function. Routing headers or function names can be composed using a comma- or pipe-separated name. The header is also added to outgoing messages from a supplier. Messages with no route key can be routed exclusively to a function or consumer by specifying spring.cloud.function.stream.{processor,sink}.name. If a single function cannot be identified to process an incoming message there will be an error, unless you set spring.cloud.function.stream.shared=true, in which case such messages will be sent to all compatible functions. A single supplier can be chosen for output messages from a supplier (if more than one is available) using the spring.cloud.function.stream.source.name.

[Note]Note

some binders will fail on startup if the message broker is not available and the function catalog contains suppliers that immediately produce messages when accessed. You can switch off the automatic publishing from suppliers on startup using the spring.cloud.function.strean.supplier.enabled=false flag.

Prev   Next
5. Standalone Web Applications Home 7. Deploying a Packaged Function
\ No newline at end of file + 6. Standalone Streaming Applications
6. Standalone Streaming Applications
Prev   Next

6. Standalone Streaming Applications

To send or receive messages from a broker (such as RabbitMQ or Kafka) you can leverage spring-cloud-stream project and it’s integration with Spring Cloud Function. +Please refer to Spring Cloud Function section of the Spring Cloud Stream reference manual for more details and examples.

Prev   Next
5. Standalone Web Applications Home 7. Deploying a Packaged Function
\ No newline at end of file diff --git a/multi/multi_pr01.html b/multi/multi_pr01.html index bb3193e1f..8500d459b 100644 --- a/multi/multi_pr01.html +++ b/multi/multi_pr01.html @@ -1,3 +1,3 @@ -
Prev   Next

Mark Fisher, Dave Syer

Prev   Next
Spring Cloud Function Home 1. Introduction
\ No newline at end of file +
Prev   Next

Mark Fisher, Dave Syer, Oleg Zhurakousky

Prev   Next
Spring Cloud Function Home 1. Introduction
\ No newline at end of file diff --git a/single/spring-cloud-function.html b/single/spring-cloud-function.html index f9755359f..e9dc133a9 100644 --- a/single/spring-cloud-function.html +++ b/single/spring-cloud-function.html @@ -1,6 +1,6 @@ - Spring Cloud Function

Spring Cloud Function

Table of Contents

1. Introduction
2. Getting Started
3. Building and Running a Function
4. Function Catalog and Flexible Function Signatures
5. Standalone Web Applications
6. Standalone Streaming Applications
7. Deploying a Packaged Function
8. Dynamic Compilation
9. Serverless Platform Adapters
9.1. AWS Lambda
9.1.1. Introduction
9.1.2. Notes on JAR Layout
9.1.3. Upload
9.1.4. Platfom Specific Features
HTTP and API Gateway
9.2. Azure Functions
9.2.1. Notes on JAR Layout
9.2.2. JSON Configuration
9.2.3. Build
9.2.4. Running the sample
9.3. Apache Openwhisk
9.3.1. Quick Start

Mark Fisher, Dave Syer

1. Introduction

Spring Cloud Function is a project with the following high-level goals:

  • Promote the implementation of business logic via functions.
  • Decouple the development lifecycle of business logic from any specific runtime target so that the same code can run as a web endpoint, a stream processor, or a task.
  • Support a uniform programming model across serverless providers, as well as the ability to run standalone (locally or in a PaaS).
  • Enable Spring Boot features (auto-configuration, dependency injection, metrics) on serverless providers.

It abstracts away all of the transport details and + Spring Cloud Function

Spring Cloud Function

Table of Contents

1. Introduction
2. Getting Started
3. Building and Running a Function
4. Function Catalog and Flexible Function Signatures
5. Standalone Web Applications
6. Standalone Streaming Applications
7. Deploying a Packaged Function
8. Dynamic Compilation
9. Serverless Platform Adapters
9.1. AWS Lambda
9.1.1. Introduction
9.1.2. Notes on JAR Layout
9.1.3. Upload
9.1.4. Platfom Specific Features
HTTP and API Gateway
9.2. Azure Functions
9.2.1. Notes on JAR Layout
9.2.2. JSON Configuration
9.2.3. Build
9.2.4. Running the sample
9.3. Apache Openwhisk
9.3.1. Quick Start

Mark Fisher, Dave Syer, Oleg Zhurakousky

1. Introduction

Spring Cloud Function is a project with the following high-level goals:

  • Promote the implementation of business logic via functions.
  • Decouple the development lifecycle of business logic from any specific runtime target so that the same code can run as a web endpoint, a stream processor, or a task.
  • Support a uniform programming model across serverless providers, as well as the ability to run standalone (locally or in a PaaS).
  • Enable Spring Boot features (auto-configuration, dependency injection, metrics) on serverless providers.

It abstracts away all of the transport details and infrastructure, allowing the developer to keep all the familiar tools and processes, and focus firmly on business logic.

Here’s a complete, executable, testable Spring Boot application (implementing a simple string manipulation):

@SpringBootApplication
@@ -77,7 +77,8 @@ getting started experience.
With the web configurations activated your app
 endpoint (on "/" by default, but configurable with
 spring.cloud.function.web.path) that can be used to access the
 functions in the application context. The supported content types are
-plain text and JSON.
MethodPathRequestResponseStatus
GET
/{supplier}
-
Items from the named supplier
200 OK
POST
/{consumer}
JSON object or text
Mirrors input and pushes request body into consumer
202 Accepted
POST
/{consumer}
JSON array or text with new lines
Mirrors input and pushes body into consumer one by one
202 Accepted
POST
/{function}
JSON object or text
The result of applying the named function
200 OK
POST
/{function}
JSON array or text with new lines
The result of applying the named function
200 OK
GET
/{function}/{item}
-
Convert the item into an object and return the result of applying the function
200 OK
As the table above shows the behaviour of the endpoint depends on the method and also the type of incoming request data. When the incoming data is single valued, and the target function is declared as obviously single valued (i.e. not returning a collection or Flux), then the response will also contain a single value. For multi-valued responses the client can ask for a server-sent event stream by sending `Accept: text/event-stream". If there is only one function (consumer etc.) then the name in the path is optional. Composite functions can be addressed using pipes or commas to separate function names (pipes are legal in URL paths, but a bit awkward to type on the command line).
Functions and consumers that are declared with input and output in Message<?> will see the request headers on the input messages, and the output message headers will be converted to HTTP headers.
When POSTing text the response format might be different with Spring Boot 2.0 and older versions, depending on the content negotiation (provide content type and accpt headers for the best results).

6. Standalone Streaming Applications

To send or receive messages from a broker (such as RabbitMQ or Kafka) you can use the spring-cloud-function-stream adapter. Add the adapter to your classpath along with the appropriate binder from Spring Cloud Stream. The adapter will bind to the message broker as a Processor (input and output streams) unless the user explicitly disables one or the other using spring.cloud.function.stream.{source,sink}.enabled=false.

An incoming message is routed to a function (or consumer). If there is only one, then the choice is obvious. If there are multiple functions that can accept an incoming message, the message is inspected to see if there is a stream_routekey header containing the name of a function. Routing headers or function names can be composed using a comma- or pipe-separated name. The header is also added to outgoing messages from a supplier. Messages with no route key can be routed exclusively to a function or consumer by specifying spring.cloud.function.stream.{processor,sink}.name. If a single function cannot be identified to process an incoming message there will be an error, unless you set spring.cloud.function.stream.shared=true, in which case such messages will be sent to all compatible functions. A single supplier can be chosen for output messages from a supplier (if more than one is available) using the spring.cloud.function.stream.source.name.

[Note]Note

some binders will fail on startup if the message broker is not available and the function catalog contains suppliers that immediately produce messages when accessed. You can switch off the automatic publishing from suppliers on startup using the spring.cloud.function.strean.supplier.enabled=false flag.

7. Deploying a Packaged Function

Spring Cloud Function provides a "deployer" library that allows you to launch a jar file (or exploded archive, or set of jar files) with an isolated class loader and expose the functions defined in it. This is quite a powerful tool that would allow you to, for instance, adapt a function to a range of different input-output adapters without changing the target jar file. Serverless platforms often have this kind of feature built in, so you could see it as a building block for a function invoker in such a platform (indeed the Riff Java function invoker uses this library).

The standard entry point of the API is the Spring configuration annotation @EnableFunctionDeployer. If that is used in a Spring Boot application the deployer kicks in and looks for some configuration to tell it where to find the function jar. At a minimum the user has to provide a function.location which is a URL or resource location for the archive containing the functions. It can optionally use a maven: prefix to locate the artifact via a dependency lookup (see FunctionProperties for complete details). A Spring Boot application is bootstrapped from the jar file, using the MANIFEST.MF to locate a start class, so that a standard Spring Boot fat jar works well, for example. If the target jar can be launched successfully then the result is a function registered in the main application’s FunctionCatalog. The registered function can be applied by code in the main application, even though it was created in an isolated class loader (by deault).

8. Dynamic Compilation

There is a sample app that uses the function compiler to create a +plain text and JSON.

MethodPathRequestResponseStatus

GET

/{supplier}

-

Items from the named supplier

200 OK

POST

/{consumer}

JSON object or text

Mirrors input and pushes request body into consumer

202 Accepted

POST

/{consumer}

JSON array or text with new lines

Mirrors input and pushes body into consumer one by one

202 Accepted

POST

/{function}

JSON object or text

The result of applying the named function

200 OK

POST

/{function}

JSON array or text with new lines

The result of applying the named function

200 OK

GET

/{function}/{item}

-

Convert the item into an object and return the result of applying the function

200 OK

As the table above shows the behaviour of the endpoint depends on the method and also the type of incoming request data. When the incoming data is single valued, and the target function is declared as obviously single valued (i.e. not returning a collection or Flux), then the response will also contain a single value. For multi-valued responses the client can ask for a server-sent event stream by sending `Accept: text/event-stream". If there is only one function (consumer etc.) then the name in the path is optional. Composite functions can be addressed using pipes or commas to separate function names (pipes are legal in URL paths, but a bit awkward to type on the command line).

Functions and consumers that are declared with input and output in Message<?> will see the request headers on the input messages, and the output message headers will be converted to HTTP headers.

When POSTing text the response format might be different with Spring Boot 2.0 and older versions, depending on the content negotiation (provide content type and accpt headers for the best results).

6. Standalone Streaming Applications

To send or receive messages from a broker (such as RabbitMQ or Kafka) you can leverage spring-cloud-stream project and it’s integration with Spring Cloud Function. +Please refer to Spring Cloud Function section of the Spring Cloud Stream reference manual for more details and examples.

7. Deploying a Packaged Function

Spring Cloud Function provides a "deployer" library that allows you to launch a jar file (or exploded archive, or set of jar files) with an isolated class loader and expose the functions defined in it. This is quite a powerful tool that would allow you to, for instance, adapt a function to a range of different input-output adapters without changing the target jar file. Serverless platforms often have this kind of feature built in, so you could see it as a building block for a function invoker in such a platform (indeed the Riff Java function invoker uses this library).

The standard entry point of the API is the Spring configuration annotation @EnableFunctionDeployer. If that is used in a Spring Boot application the deployer kicks in and looks for some configuration to tell it where to find the function jar. At a minimum the user has to provide a function.location which is a URL or resource location for the archive containing the functions. It can optionally use a maven: prefix to locate the artifact via a dependency lookup (see FunctionProperties for complete details). A Spring Boot application is bootstrapped from the jar file, using the MANIFEST.MF to locate a start class, so that a standard Spring Boot fat jar works well, for example. If the target jar can be launched successfully then the result is a function registered in the main application’s FunctionCatalog. The registered function can be applied by code in the main application, even though it was created in an isolated class loader (by deault).

8. Dynamic Compilation

There is a sample app that uses the function compiler to create a function from a configuration property. The vanilla "function-sample" also has that feature. And there are some scripts that you can run to see the compilation happening at run time. To run these examples, diff --git a/spring-cloud-function.xml b/spring-cloud-function.xml index cf88e81c6..050ed51fc 100644 --- a/spring-cloud-function.xml +++ b/spring-cloud-function.xml @@ -8,7 +8,7 @@ -Mark Fisher, Dave Syer +Mark Fisher, Dave Syer, Oleg Zhurakousky @@ -283,11 +283,8 @@ plain text and JSON. Standalone Streaming Applications -To send or receive messages from a broker (such as RabbitMQ or Kafka) you can use the spring-cloud-function-stream adapter. Add the adapter to your classpath along with the appropriate binder from Spring Cloud Stream. The adapter will bind to the message broker as a Processor (input and output streams) unless the user explicitly disables one or the other using spring.cloud.function.stream.{source,sink}.enabled=false. -An incoming message is routed to a function (or consumer). If there is only one, then the choice is obvious. If there are multiple functions that can accept an incoming message, the message is inspected to see if there is a stream_routekey header containing the name of a function. Routing headers or function names can be composed using a comma- or pipe-separated name. The header is also added to outgoing messages from a supplier. Messages with no route key can be routed exclusively to a function or consumer by specifying spring.cloud.function.stream.{processor,sink}.name. If a single function cannot be identified to process an incoming message there will be an error, unless you set spring.cloud.function.stream.shared=true, in which case such messages will be sent to all compatible functions. A single supplier can be chosen for output messages from a supplier (if more than one is available) using the spring.cloud.function.stream.source.name. - -some binders will fail on startup if the message broker is not available and the function catalog contains suppliers that immediately produce messages when accessed. You can switch off the automatic publishing from suppliers on startup using the spring.cloud.function.strean.supplier.enabled=false flag. - +To send or receive messages from a broker (such as RabbitMQ or Kafka) you can leverage spring-cloud-stream project and it’s integration with Spring Cloud Function. +Please refer to Spring Cloud Function section of the Spring Cloud Stream reference manual for more details and examples. Deploying a Packaged Function