This project allows you to expose your Java project/library as a REST service. It allows you to make calls to Java code from any language or framework you are in.
- Release Notes
- Implementing The Bridge Service in Your Project
- Starting the Bridge Service
- Setting Information About your Environment
- Testing That all is Working
- Testing That all External Dervices can be Accessed
- Making a basic Java Call
- Instantiating Objects
- Managing Timeouts
- Call Chaining a basic Java Call
- Creating a Call Context
- Error Management
- Contribution
- Known Errors
- Known Issues and Limitations
The release notes can be found here.
The bridge service can be used in two ways:
- By adding it to the project you want to expose (recommended),
- By including your project as a dependency to the Bridge cervice deployed.
We think it is simplest to the BridgeService dependency to your project. This allows you to only update your code when needed, and you do not need to create a new release/snapshot everytime your project changes.
When starting the bridge service you need to run the following command line:
mvn compile exec:java -Dexec.mainClass=MainContainer -Dexec.args="test"
The following dependency needs to be added to your pom file:
<dependency>
<groupId>com.adobe.campaign.tests.bridge.service</groupId>
<artifactId>integroBridgeService</artifactId>
<version>2.11.15</version>
</dependency>
Since the BridgeService uses Jetty and java Spark, it is quite possible that there maybe conflicts in the project when you add this library. Most importantly you will need to ensure that javax.servlet is set to "compile" in your maven scope.
We have found it simplest to simply add that library directly in the pom file with the scope "compile".
In this model you can simply add your project as a dependency to the BridgeProject.
When deploying this as a project we run this as an executable jar. This is usually done in a Docker image.
You can also run the project locally to debug your project. To do this, you need to run the following command line:
from the root project:
mvn -pl integroBridgeService exec:java -Dexec.args="test"
or directly from the module "integroBridgeService":
mvn exec:java -Dexec.args="test"
This will make the service available under :
http://localhost:8080
The bridge service can be launched in this project with a demo project (Included in an aggregator mode). When deployed in this mode, we include the module bridgeService-data which is part of this project. If you want to include this project in your deployment you need to set the property demo.project.mode to compile.
from the root project:
mvn -pl integroBridgeService exec:java -Dexec.args="test" -Ddemo.project.mode=compile
or directly from the module "integroBridgeService":
mvn exec:java -Dexec.args="test" -Ddemo.project.mode=compile
The users accessing bridge service will encounter two different technologies:
- The Bridge Service
- The Host Project
In order to make provide context information the Bridge Service will always let you know which version it is. However, we need to let the users know about the version of the host project. Ths version number can be set by setting the environment property IBS.PRODUCT.USER.VERSION.
All you need to do is to call :
/test
If all is good you should get:
All systems up - in production
Version : 2.11.15
Product user version : 7.0
Note: The 'Product user version' is a value that you set in the environment variables, and is intended for the consumers.
One of the added values of this service is to create a single point of access for external dependencies. However, this needs to be checked, before using this service. In order to do this you need to the following POST call:
/service-check
The payload needs to have the following format:
{
"<URL ID 1>": "<dns 1>:<Port>",
"<URL ID 2>": "<dns 2>:<Port>"
}The payload returns a JSON with the test results:
{
"<URL ID 1>": true,
"<URL ID 2>": false
}In the example above "<URL ID 2>" is marked as false because it can not be accessed from the BridgeService.
The simplest java call is done in the following way:
/call
{
"callContent": {
"<ID>": {
"class": "<package name>.<class Name>",
"method": "<method name>",
"args": ["argument1","argument2"]
}
}
}If the IntegroBridgeService can find the method it will execute it. The result is, when successful, is encapsulated in a 'returnValues' object.
{
"returnValues": {
"<ID>": "<result>"
},
"callDurations": {
"<ID>": "<duration ms>"
}
}If we do not specify a method, the bridge service assumes that we are instantiating the given class:
{
"callContent": {
"<ID>": {
"class": "<package name>.<class Name>",
"args": ["argument1","argument2"]
}
}
}Note : You can also set the method name to the class name, but it may be easier to simply skip setting a method name in this case.
As of version 2.11.6 we now introduce the notion of timeouts. This means that after a declared time a call will be interrupted. Setting this value can be done at two levels:
- The deployment level
- The Call session
Note : If set to 0, there is no timeout.
You can set a default value when starting the service. This is done by setting the environment variable IBS.TIMEOUT.DEFAULT. If not set, the default value is 10000ms.
We can also set the Timeout for a java call transaction. In that case the value you pass overrides the global value, but only for you session. If the timeout is not test in the payload at the next call, the global value will be used.
In the example below the method methodWithTimeOut waits for the provided, in this case 800ms, amount of time. In the example below the test will pass because we wait for 800ms, and the timeout is 1000s.
{
"callContent": {
"call1": {
"class": "com.adobe.campaign.tests.bridge.testdata.one.SimpleStaticMethods",
"method": "methodWithTimeOut",
"args": [
800
]
}
},
"timeout": 1000
}If the payload above would have a timeout below 800ms, the call will fail.
We can chain a series of java calls in the same payload:
{
"callContent": {
"<ID-1>": {
"class": "<package name 1>.<class name 1>",
"method": "<method name 1>",
"args": ["argument1","argument2"]
},
"<ID-2>": {
"class": "<package name 2>.<class name 2>",
"method": "<method name 2>",
"args": ["argument1","argument2"]
}
}
}In the example above the results will be stored in the following way:
{
"returnValues": {
"<ID-1>": "<result>",
"<ID-2>": "<result>"
},
"callDurations": {
"<ID-1>": "<duration ms>",
"<ID-2>": "<duration ms>"
}
}We now have the possibility of injecting call results from one call to the other:
{
"callContent": {
"<ID-1>": {
"class": "<package name 1>.<class name 1>",
"method": "<method name 1>",
"args": ["argument1","argument2"]
},
"<ID-2>": {
"class": "<package name 2>.<class name 2>",
"method": "<method name 2>",
"args": ["<ID-1>","argument2"]
}
}
}In the example above "ID-2" will use the return value of the call "ID-1" as ts first argument.
NOTE : When passing a call result as an argument, it needs to be a String. In many languages such as JavaScript, the JSON keys need not be a string, however, for this to work you need to pass the ID as a string.
We now have the possibility of injecting call results from one call to the other. In the example below we instantiate an object, and in the following call we call a method of that object. This is done by passing the ID of the first call as the instance value for the following call.
{
"callContent": {
"<ID-1>": {
"class": "<package name>.<class name>",
"args": ["argument1","argument2"]
},
"<ID-2>": {
"class": "<ID-1>",
"method": "<method name>",
"args": ["argument2"]
}
}
}In the example above "ID-2" will use call the instance method of the object created in call "ID-1".
We sometimes need to set environment variables when making calls. This is usually indirectly related to the call you are doing. These variable mirror the values of a property file, so they are always treated as strings.
{
"callContent": {
"<ID>": {
"class": "<package name>.<class Name>",
"method": "<method name>",
"args": ["argument1","argument2"]
}
},
"environmentVariables": {
"<ENVIRONMENT PROPERTY 1>": "<value>"
}
}When making the call we first update the environment variables for the system.
This call will use your internal method for setting environment variables. This method can be set by setting the following environment values, when activating the Bridge on your project:
- IBS.ENVVARS.SETTER.CLASS
- IBS.ENVVARS.SETTER.METHOD
One of our main concerns has been the management of static variables. For the sake of conversation we need to identify scopes:
- Session Scope : Access to the variables in the same call to the Bridge Service
- Product Scope : Access to the variables between two different calls
For now our approach is that two distinct calls to the same Bridge Service node, should share little or no variables. Another way of defining this is that two calls should not interfere with one another. In a Session Context we have two use cases:
We have covered all the use cases in the document Managing Contexts and Static Variables.
Although we do not, yet, provide tools for managing variables that are valid for all calls to the IBS, we can define a series or local environment variables are deployment of the service. This can be done in two ways:
- Managing a properties for in your deployment
- Injecting Runtime properties at the commandline
Currently, whenever there is an error in the underlying java call we will include the orginal error message in the error response. For example, for the call:
{
"callContent": {
"call1": {
"class": "com.adobe.campaign.tests.bridge.testdata.one.SimpleStaticMethods",
"method": "methodThrowingException",
"returnType": "java.lang.String",
"args": [
3,
3
]
}
}
}We would normally get the error:
java.lang.IllegalArgumentException: We do not allow numbers that are equal.
When using the bridge service, we also include additional info:
{
"title": "A title describing the exception",
"code": 500,
"detail": "A detailed description of the problem",
"bridgeServiceException": "com.adobe.campaign.tests.bridge.service.exceptions.TargetJavaMethodCallException",
"originalException": "java.lang.IllegalArgumentException",
"originalMessage": "The message of the originating exception",
"failureAtStep": "Step name",
"stackTrace": [
"ClassA.methodA",
"ClassB.methodB"
]
}The BridgeService exception is how the bridgeService manages underlying errors. However, we also share the:
- The title of the failure
- The error code
- The bridgeService error category
- The Originating exception
- The Originating exception message
- The step at which the error occured
- The stack trace of the originating exception
There are two main docs for contributing:
- The Contributing Doc For general contribution rules.
- The Technical Doc For general technical aspects.
When using the "manual" mode, this error can happen when you are chaining calls, and that the called classes call a third class in a static way. In such cases you will get an error like:
Problems with payload. Check the passed environment variables.
java.lang.LinkageError: loader constraint violation: when resolving method "com.adobe.campaign.tests.bridge.testdata.issue34.pckg2.MiddleManClassFactory.getMarketingInstance()Lcom/adobe/campaign/tests/bridge/testdata/issue34/pckg1/MiddleMan;" the class loader com.adobe.campaign.tests.bridge.service.IntegroBridgeClassLoader @697a1a68 (instance of com.adobe.campaign.tests.bridge.service.IntegroBridgeClassLoader, child of 'app' jdk.internal.loader.ClassLoaders$AppClassLoader) of the current class, com/adobe/campaign/tests/bridge/testdata/issue34/pckg1/CalledClass2, and the class loader 'app' (instance of jdk.internal.loader.ClassLoaders$AppClassLoader) for the method's defining class, com/adobe/campaign/tests/bridge/testdata/issue34/pckg2/MiddleManClassFactory, have different Class objects for the type com/adobe/campaign/tests/bridge/testdata/issue34/pckg1/MiddleMan used in the signature
This usually means that some additional packages need to be included in the environment variable: IBS.CLASSLOADER.STATIC.INTEGRITY.PACKAGES.
As this is a new project there are a few limitations to our solution:
Today, in order to simply the call model, we have chosen not to specify the argument types in the call. The consequence of this is that in the case of overloaded methods, we only pick the method with the same number of arguments. If two such overloaded methods exist, we choose to throw an exception:
We could not find a unique method for <method>.
Since this is a REST call we can only correctly manage simple arguments in the payload. One workaround is to use Call Dependencies in Call Chaining (see above). I.e. you can pass simple arguments to one method, and use the complex results of that method as an argument for the following java call.
In many cases the object a method returns is not serializable. If that is the case we mine the object, and extract all simple values from the object.
We are currently unable to call enums with the Bridge Service.