public interface BackendServiceBackendService allows you to retrieve information about backend servers. Backend servers are long running addressable servers that can be used for applications that need to keep persistent state in ram between requests.
This API is deprecated and has been replaced by com.google.appengine.api.modules.ModulesService. Please update your code as soon as possible. See the modules documentation for more information: https://developers.google.com/appengine/docs/java/modules/converting
This API allows you to retrieve information about the backend handling the current request. It also allows you to to get the address of a specific backend instance in such a way that a local server is used during development and a production server is used in production.
Static Fields
BACKEND_ID_ENV_ATTRIBUTE
public static final String BACKEND_ID_ENV_ATTRIBUTEEnvironment attribute key where the backend name is stored. See Also: BackendService#getCurrentBackend()
| Field Value | |
|---|---|
| Type | Description |
String |
|
DEVAPPSERVER_PORTMAPPING_KEY
public static final String DEVAPPSERVER_PORTMAPPING_KEY| Field Value | |
|---|---|
| Type | Description |
String |
|
INSTANCE_ID_ENV_ATTRIBUTE
public static final String INSTANCE_ID_ENV_ATTRIBUTEEnvironment attribute key where the instance id is stored. See Also: BackendService#getCurrentInstance()
| Field Value | |
|---|---|
| Type | Description |
String |
|
REQUEST_HEADER_BACKEND_REDIRECT
public static final String REQUEST_HEADER_BACKEND_REDIRECT| Field Value | |
|---|---|
| Type | Description |
String |
|
REQUEST_HEADER_INSTANCE_REDIRECT
public static final String REQUEST_HEADER_INSTANCE_REDIRECT| Field Value | |
|---|---|
| Type | Description |
String |
|
Methods
getBackendAddress(String backend)
public abstract String getBackendAddress(String backend)Get the address of a specific backend in such a way that a local server is used during development and a production server is used in production.
| Parameter | |
|---|---|
| Name | Description |
backend |
StringThe name of the backend |
| Returns | |
|---|---|
| Type | Description |
String |
The address of the backend |
getBackendAddress(String backend, int instance)
public abstract String getBackendAddress(String backend, int instance)Get the address of a specific backend instance in such a way that a local instance is used during development and a production server instance is used in production.
| Parameters | |
|---|---|
| Name | Description |
backend |
StringThe name of the backend |
instance |
intThe instance id |
| Returns | |
|---|---|
| Type | Description |
String |
The address of the backend instance |
getCurrentBackend()
public abstract String getCurrentBackend()Get the name of the backend handling the current request.
| Returns | |
|---|---|
| Type | Description |
String |
The name of the backend or null if the request is not handled by a backend. |
getCurrentInstance()
public abstract int getCurrentInstance()Get the instance handling the current request.
| Returns | |
|---|---|
| Type | Description |
int |
The instance id or -1 if the request is not handled by a backend. |