From 830ca1e662ec840214ec85f6ad2c219d5b7009c8 Mon Sep 17 00:00:00 2001 From: buildmaster Date: Mon, 7 Jan 2019 14:36:32 +0000 Subject: [PATCH] Sync docs from master to gh-pages --- multi/multi_spring-cloud-feign.html | 19 ++++++++++++++++--- single/spring-cloud-openfeign.html | 19 ++++++++++++++++--- spring-cloud-openfeign.xml | 21 ++++++++++++++++++++- 3 files changed, 52 insertions(+), 7 deletions(-) diff --git a/multi/multi_spring-cloud-feign.html b/multi/multi_spring-cloud-feign.html index 8461e5f3..fc62c4de 100644 --- a/multi/multi_spring-cloud-feign.html +++ b/multi/multi_spring-cloud-feign.html @@ -32,10 +32,14 @@ it will resolve the service in the Eureka service registry. If you don’t want to use Eureka, you can simply configure a list of servers in your external configuration (see above for example).

1.2 Overriding Feign Defaults

A central concept in Spring Cloud’s Feign support is that of the named client. Each feign client is part of an ensemble of components that work together to contact a remote server on demand, and the ensemble has a name that you give it as an application developer using the @FeignClient annotation. Spring Cloud creates a new ensemble as an -ApplicationContext on demand for each named client using FeignClientsConfiguration. This contains (amongst other things) an feign.Decoder, a feign.Encoder, and a feign.Contract.

Spring Cloud lets you take full control of the feign client by declaring additional configuration (on top of the FeignClientsConfiguration) using @FeignClient. Example:

@FeignClient(name = "stores", configuration = FooConfiguration.class)
+ApplicationContext on demand for each named client using FeignClientsConfiguration. This contains (amongst other things) an feign.Decoder, a feign.Encoder, and a feign.Contract.
+It is possible to override the name of that ensemble by using the contextId
+attribute of the @FeignClient annotation.
Spring Cloud lets you take full control of the feign client by declaring additional configuration (on top of the FeignClientsConfiguration) using @FeignClient. Example:
@FeignClient(name = "stores", configuration = FooConfiguration.class)
 public interface StoreClient {
     //..
-}
In this case the client is composed from the components already in FeignClientsConfiguration together with any in FooConfiguration (where the latter will override the former).
[Note]Note
FooConfiguration does not need to be annotated with @Configuration. However, if it is, then take care to exclude it from any @ComponentScan that would otherwise include this configuration as it will become the default source for feign.Decoder, feign.Encoder, feign.Contract, etc., when specified. This can be avoided by putting it in a separate, non-overlapping package from any @ComponentScan or @SpringBootApplication, or it can be explicitly excluded in @ComponentScan.
[Note]Note
The serviceId attribute is now deprecated in favor of the name attribute.
[Warning]Warning
Previously, using the url attribute, did not require the name attribute. Using name is now required.
Placeholders are supported in the name and url attributes.
@FeignClient(name = "${feign.name}", url = "${feign.url}")
+}
In this case the client is composed from the components already in FeignClientsConfiguration together with any in FooConfiguration (where the latter will override the former).
[Note]Note
FooConfiguration does not need to be annotated with @Configuration. However, if it is, then take care to exclude it from any @ComponentScan that would otherwise include this configuration as it will become the default source for feign.Decoder, feign.Encoder, feign.Contract, etc., when specified. This can be avoided by putting it in a separate, non-overlapping package from any @ComponentScan or @SpringBootApplication, or it can be explicitly excluded in @ComponentScan.
[Note]Note
The serviceId attribute is now deprecated in favor of the name attribute.
[Note]Note
Using contextId attribute of the @FeignClient annotation in addition to changing the name of
+the ApplicationContext ensemble, it will override the alias of the client name
+and it will be used as part of the name of the configuration bean created for that client.
[Warning]Warning
Previously, using the url attribute, did not require the name attribute. Using name is now required.
Placeholders are supported in the name and url attributes.
@FeignClient(name = "${feign.name}", url = "${feign.url}")
 public interface StoreClient {
     //..
 }
Spring Cloud Netflix provides the following beans by default for feign (BeanType beanName: ClassName):
  • Decoder feignDecoder: ResponseEntityDecoder (which wraps a SpringDecoder)
  • Encoder feignEncoder: SpringEncoder
  • Logger feignLogger: Slf4jLogger
  • Contract feignContract: SpringMvcContract
  • Feign.Builder feignBuilder: HystrixFeign.Builder
  • Client feignClient: if Ribbon is enabled it is a LoadBalancerFeignClient, otherwise the default feign client is used.
The OkHttpClient and ApacheHttpClient feign clients can be used by setting feign.okhttp.enabled or feign.httpclient.enabled to true, respectively, and having them on the classpath.
@@ -85,7 +89,16 @@ thread isolation strategy for Hystrix to `SEMAPHORE or disable Hystrix in
     default:
       execution:
         isolation:
-          strategy: SEMAPHORE

1.3 Creating Feign Clients Manually

In some cases it might be necessary to customize your Feign Clients in a way that is not + strategy: SEMAPHORE

If we want to create multiple feign clients with the same name or url +so that they would point to the same server but each with a different custom configuration then +we have to use contextId attribute of the @FeignClient in order to avoid name +collision of these configuration beans.

@FeignClient(contextId = "fooClient", name = "stores", configuration = FooConfiguration.class)
+public interface FooClient {
+    //..
+}
@FeignClient(contextId = "barClient", name = "stores", configuration = BarConfiguration.class)
+public interface BarClient {
+    //..
+}

1.3 Creating Feign Clients Manually

In some cases it might be necessary to customize your Feign Clients in a way that is not possible using the methods above. In this case you can create Clients using the Feign Builder API. Below is an example which creates two Feign Clients with the same interface but configures each one with diff --git a/single/spring-cloud-openfeign.html b/single/spring-cloud-openfeign.html index 16208853..af6dde74 100644 --- a/single/spring-cloud-openfeign.html +++ b/single/spring-cloud-openfeign.html @@ -33,10 +33,14 @@ it will resolve the service in the Eureka service registry. If you don’t want to use Eureka, you can simply configure a list of servers in your external configuration (see above for example).

1.2 Overriding Feign Defaults

A central concept in Spring Cloud’s Feign support is that of the named client. Each feign client is part of an ensemble of components that work together to contact a remote server on demand, and the ensemble has a name that you give it as an application developer using the @FeignClient annotation. Spring Cloud creates a new ensemble as an -ApplicationContext on demand for each named client using FeignClientsConfiguration. This contains (amongst other things) an feign.Decoder, a feign.Encoder, and a feign.Contract.

Spring Cloud lets you take full control of the feign client by declaring additional configuration (on top of the FeignClientsConfiguration) using @FeignClient. Example:

@FeignClient(name = "stores", configuration = FooConfiguration.class)
+ApplicationContext on demand for each named client using FeignClientsConfiguration. This contains (amongst other things) an feign.Decoder, a feign.Encoder, and a feign.Contract.
+It is possible to override the name of that ensemble by using the contextId
+attribute of the @FeignClient annotation.
Spring Cloud lets you take full control of the feign client by declaring additional configuration (on top of the FeignClientsConfiguration) using @FeignClient. Example:
@FeignClient(name = "stores", configuration = FooConfiguration.class)
 public interface StoreClient {
     //..
-}
In this case the client is composed from the components already in FeignClientsConfiguration together with any in FooConfiguration (where the latter will override the former).
[Note]Note
FooConfiguration does not need to be annotated with @Configuration. However, if it is, then take care to exclude it from any @ComponentScan that would otherwise include this configuration as it will become the default source for feign.Decoder, feign.Encoder, feign.Contract, etc., when specified. This can be avoided by putting it in a separate, non-overlapping package from any @ComponentScan or @SpringBootApplication, or it can be explicitly excluded in @ComponentScan.
[Note]Note
The serviceId attribute is now deprecated in favor of the name attribute.
[Warning]Warning
Previously, using the url attribute, did not require the name attribute. Using name is now required.
Placeholders are supported in the name and url attributes.
@FeignClient(name = "${feign.name}", url = "${feign.url}")
+}
In this case the client is composed from the components already in FeignClientsConfiguration together with any in FooConfiguration (where the latter will override the former).
[Note]Note
FooConfiguration does not need to be annotated with @Configuration. However, if it is, then take care to exclude it from any @ComponentScan that would otherwise include this configuration as it will become the default source for feign.Decoder, feign.Encoder, feign.Contract, etc., when specified. This can be avoided by putting it in a separate, non-overlapping package from any @ComponentScan or @SpringBootApplication, or it can be explicitly excluded in @ComponentScan.
[Note]Note
The serviceId attribute is now deprecated in favor of the name attribute.
[Note]Note
Using contextId attribute of the @FeignClient annotation in addition to changing the name of
+the ApplicationContext ensemble, it will override the alias of the client name
+and it will be used as part of the name of the configuration bean created for that client.
[Warning]Warning
Previously, using the url attribute, did not require the name attribute. Using name is now required.
Placeholders are supported in the name and url attributes.
@FeignClient(name = "${feign.name}", url = "${feign.url}")
 public interface StoreClient {
     //..
 }
Spring Cloud Netflix provides the following beans by default for feign (BeanType beanName: ClassName):
  • Decoder feignDecoder: ResponseEntityDecoder (which wraps a SpringDecoder)
  • Encoder feignEncoder: SpringEncoder
  • Logger feignLogger: Slf4jLogger
  • Contract feignContract: SpringMvcContract
  • Feign.Builder feignBuilder: HystrixFeign.Builder
  • Client feignClient: if Ribbon is enabled it is a LoadBalancerFeignClient, otherwise the default feign client is used.
The OkHttpClient and ApacheHttpClient feign clients can be used by setting feign.okhttp.enabled or feign.httpclient.enabled to true, respectively, and having them on the classpath.
@@ -86,7 +90,16 @@ thread isolation strategy for Hystrix to `SEMAPHORE or disable Hystrix in
     default:
       execution:
         isolation:
-          strategy: SEMAPHORE

1.3 Creating Feign Clients Manually

In some cases it might be necessary to customize your Feign Clients in a way that is not + strategy: SEMAPHORE

If we want to create multiple feign clients with the same name or url +so that they would point to the same server but each with a different custom configuration then +we have to use contextId attribute of the @FeignClient in order to avoid name +collision of these configuration beans.

@FeignClient(contextId = "fooClient", name = "stores", configuration = FooConfiguration.class)
+public interface FooClient {
+    //..
+}
@FeignClient(contextId = "barClient", name = "stores", configuration = BarConfiguration.class)
+public interface BarClient {
+    //..
+}

1.3 Creating Feign Clients Manually

In some cases it might be necessary to customize your Feign Clients in a way that is not possible using the methods above. In this case you can create Clients using the Feign Builder API. Below is an example which creates two Feign Clients with the same interface but configures each one with diff --git a/spring-cloud-openfeign.xml b/spring-cloud-openfeign.xml index ad902676..8cb6e030 100644 --- a/spring-cloud-openfeign.xml +++ b/spring-cloud-openfeign.xml @@ -61,7 +61,9 @@ in your external configuration (see

Overriding Feign Defaults A central concept in Spring Cloud’s Feign support is that of the named client. Each feign client is part of an ensemble of components that work together to contact a remote server on demand, and the ensemble has a name that you give it as an application developer using the @FeignClient annotation. Spring Cloud creates a new ensemble as an -ApplicationContext on demand for each named client using FeignClientsConfiguration. This contains (amongst other things) an feign.Decoder, a feign.Encoder, and a feign.Contract. +ApplicationContext on demand for each named client using FeignClientsConfiguration. This contains (amongst other things) an feign.Decoder, a feign.Encoder, and a feign.Contract. +It is possible to override the name of that ensemble by using the contextId +attribute of the @FeignClient annotation. Spring Cloud lets you take full control of the feign client by declaring additional configuration (on top of the FeignClientsConfiguration) using @FeignClient. Example: @FeignClient(name = "stores", configuration = FooConfiguration.class) public interface StoreClient { @@ -74,6 +76,11 @@ public interface StoreClient { The serviceId attribute is now deprecated in favor of the name attribute. + +Using contextId attribute of the @FeignClient annotation in addition to changing the name of +the ApplicationContext ensemble, it will override the alias of the client name +and it will be used as part of the name of the configuration bean created for that client. + Previously, using the url attribute, did not require the name attribute. Using name is now required. @@ -188,6 +195,18 @@ hystrix: execution: isolation: strategy: SEMAPHORE +If we want to create multiple feign clients with the same name or url +so that they would point to the same server but each with a different custom configuration then +we have to use contextId attribute of the @FeignClient in order to avoid name +collision of these configuration beans. +@FeignClient(contextId = "fooClient", name = "stores", configuration = FooConfiguration.class) +public interface FooClient { + //.. +} +@FeignClient(contextId = "barClient", name = "stores", configuration = BarConfiguration.class) +public interface BarClient { + //.. +}
Creating Feign Clients Manually