BridgeService

The BridgeService 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.

BridgeService

Background

We originally created this project to address the need for Cypress tests to reuse code created for the back-end tests. We had a lot of product knowledge and tooling stored in the back-end tests, that rewriting them in node would not have been practical. Today the project is up and running and is used regularly in our test projects.

Demo Project

We have created a demo project that shpws how the bridge service can be implemented. It is available under Test As A Product Demo.

Release Notes

The release notes can be found here.

Implementing The Bridge Service in Your Project

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.

Adding the Bridge Service to Your Project

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.

BridgeService Injection Model

When starting the bridge service you need to run the following command line:

mvn compile exec:java -Dexec.mainClass=MainContainer -Dexec.args="test"

Installation

The following dependency needs to be added to your pom file:

<dependency>
    <groupId>com.adobe.campaign.tests.bridge.service</groupId>
    <artifactId>integroBridgeService</artifactId>
    <version>2.11.18</version>
</dependency>

Considerations

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".

Including your project in the BridgeService

In this model you can simply add your project as a dependency to the BridgeProject.

BridgeService Aggregator Model

Starting the Bridge Service

When deploying this as a project we run this as an executable jar. This is usually done in a Docker image.

Running the Bridge Locally

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

Running a DEMO

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

Setting Information About your Environment

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.

Testing That all is Working

All you need to do is to call : /test

If all is good you should get:

All systems up - in production
Version : 2.11.16
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.

Testing That all External Devices can be Accessed

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.

Making Java Calls

A basic Java Call

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>"
  }
}

Here is an example for the POST call http://localhost:8080/call and the payload:

{
  "callContent": {
    "fetchString1": {
      "class": "com.adobe.campaign.tests.bridge.testdata.one.SimpleStaticMethods",
      "method": "methodAcceptingStringArgument",
      "args": [
        "REAL"
      ]
    }
  }
}

SimpleStaticMethods.methodAcceptingStringArgument accepts a string argument and concatenates the given argument with _SUCCESS. The call will return the following result:

{
  "callDurations": {
    "fetchString1": 7
  },
  "returnValues": {
    "fetchString1": "REAL_Success"
  }
}

Instantiating Objects

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.

Call Chaining a basic Java Call

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>"
  }
}

Call Chaining and Call Dependencies

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.

Here is an example of for a call chaining:

{
  "callContent": {
    "fetchStringsList": {
      "class": "com.adobe.campaign.tests.bridge.testdata.one.SimpleStaticMethods",
      "method": "methodReturningList",
      "args": []
    },
    "fetchSubjects": {
      "class": "com.adobe.campaign.tests.bridge.testdata.one.SimpleStaticMethods",
      "method": "methodAcceptingListArguments",
      "args": [
        "fetchStringsList"
      ]
    }
  }
}

methodReturningList returns a list of Strings. methodAcceptingListArguments accepts a list and returns its size. As you can see we have passed the identity of the first call, fetchStringsList to the second one fetchSubjects. Here is the return payload:

{
  "callDurations": {
    "fetchStringsList": 5,
    "fetchSubjects": 1
  },
  "returnValues": {
    "fetchStringsList": [
      "NA1",
      "NA2",
      "NA3",
      "NA4"
    ],
    "fetchSubjects": 4
  }
}

Call Chaining and Instance Methods

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".

Argument Types

Since we are using JSON to pass values to the method, we need to cover how different types are passed.

Simple Java Objects

The internal Java objects such as int, String and boolean can be passed with no problems

Lists and Arrays

List and Arrays can be passed as JSONArrays. IBS will transform them to the target argument when needed (Available since 2.116).

Complex Types

Some methods require complex Objects as arguments. In this case you need to have a constructor/factory call in one call, and pass they key as an argument.

Files

As of version 2.11.16 we have the possibility to pass a file to the bridgeService. When doing so, you need to send your request as a multi-part request. As in most multi-part requests, you need to give each uploaded file a key value. In that case the file is referenced with that key value.

Below is an example using curl (executed from the project root). We are uploading the file integroBridgeService/src/test/resources/uploadFiles/testaRosa.txt with the id uploaded_file, like in call chaining we have passed this id to the method call fileReader, whose job is to return the file contents.

curl --request POST \
  --url http://localhost:8080/call \
  --header 'Content-Type: multipart/form-data' \
  --form 'jsonbody={
        "assertions": {},
        "timeout": 10000,
        "callContent": {
                "fileReader": {
                        "class": "com.adobe.campaign.tests.bridge.testdata.one.SimpleStaticMethods",
                        "method": "methodAcceptingFile",
                        "args": [
                                "uploaded_file"
                        ]

                }
        },
        "environmentVariables": {}
}' \
  --form uploaded_file=@integroBridgeService/src/test/resources/uploadFiles/testaRosa.txt

The result is then:

{
  "callDurations": {
    "call1PL": 7
  },
  "returnValues": {
    "fileReader": "Hello World"
  }
}

Results

Results are returned as a JSON Object. Serializable return objects are deserialized. For objects that are not Serializable, we perform an operatio called scraping, which involves sequentially calling the simple getters of the object, and include the results in the result object.

In the case of complex classes where the scraping is not sufficient, you can define a deserialization plugin for that class. This allow you to be specific regarding how the object can be returned. For mor information on this you can refer to the chapter Deserialization Plugins.

Formatting Dates

We now allow the extraction and the formatting of Dates. This is done by setting the environment variable IBS.DESERIALIZATION.DATE.FORMAT. If not set the date is not changed and remains a long. The format we cover is SimpleDateFormat. A wrong Date format will result in using the default format (long).

Deserialization Plugins

As of version 2.11.17, we introduced the notion of plugins. For now you can customize how an object is deserialized. This can be usefull when the default object serialization is incomplete or not to your liking.

To create your own plugin you need to:

Implement the interface methods of the interface com.adobe.campaign.tests.bridge.service.plugins.IBSDeserializerPlugin.
Flag the package of the plugin in the environment variable IBS.PLUGINS.PACKAGE.

There is an example of the plugin in the tests under integroBridgeService/src/test/java/com/adobe/campaign/tests/bridge/plugins/deserializer/MimeExtractionPluginDeserializer.java.

Managing Timeouts

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.

Setting Timeout Globally

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.

Setting a Timeout for the Call Session

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.

Creating a Call Context

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

Static Variable Scopes

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

Session Scopes

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.

Product Scope

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

Headers and Secrets

As of version 2.11.16, we can now use header variables in the payload. This feature was developed for two reasons:

Avoiding the passing o secrets directly in the JSON payload.
Allowing for users to re-use the same JSON payload for different values.

All you need to do is to reference your header name in the args section.

Example:

curl --request POST \
  --url http://localhost:8080/call \
  --header 'Content-Type: application/json' \
  --header 'ibs-header-var1: MyValue' \
  --data '{
    "callContent": {
        "fetchHeader": {
            "class": "com.adobe.campaign.tests.bridge.testdata.one.SimpleStaticMethods",
            "method": "methodAcceptingStringArgument",
            "args": [
                "ibs-header-var1"
            ]
        }
    }
}'

In the call above we pass MyValue with the key ibs-header-var1 as a header. Our payload will fetch the value in the argssection. The call will return :

{
  "callDurations": {
    "fetchString1": 12
  },
  "returnValues": {
    "fetchString1": "MyValue_Success"
  }
}

Secrets

Secrets allow you to have an extra level of security. This will mean that we will not allow you to print the secret in the output.

A secret sent to the IBS will have to be prefixed with ibs-secret-. This can be overridden by setting the run-time variable IBS.SECRETS.FILTER.PREFIX.

In the example earlier, if MyValue were to be passed as a secret (with a prefix ibs-secret-), we would be getting an exception:

curl --request POST \
  --url http://localhost:8080/call \
  --header 'Content-Type: application/json' \
  --header 'ibs-header-var1: MyValue' \
  --data '{
    "callContent": {
        "fetchHeader": {
            "class": "com.adobe.campaign.tests.bridge.testdata.one.SimpleStaticMethods",
            "method": "methodAcceptingStringArgument",
            "args": [
                "ibs-secret-var1"
            ]
        }
    }
}'

Below is the exception we will get:

{
  "title": "We detected an inconsistency in your payload.",
  "code": 404,
  "detail": "Your return payload contains secrets. You may consider re-evaluating the headers you send. If they are not a secret, they can be put directly in the payload. Otherwise you can simply disable the IBS.HEADERS.BLOCK.OUTPUT option.",
  "bridgeServiceException": "com.adobe.campaign.tests.bridge.service.exceptions.IBSPayloadException"
}

Sometimes you may want to debug the system. In these cases you can deactivate the output check by setting run-time variable IBS.SECRETS.BLOCK.OUTPUT to false. However, this should only be temporary, and in production it is best to keep this control.

Steamlining Headers

By default, IBS stores all the headers when you send a call. You have the possibility to filter the headers you want to use by setting the run-time variable IBS.HEADERS.FILTER.PREFIX.

Making Assertions

As of version 2.11.16, we allow the user to define assertions. An assertion allows users to define acceptance criteria for a call. They can also allow users to delegate the execution to a third party, by defining what an acceptable outcome for a result should be. This has been implemented by embedding Hamcrest Matchers in the bridge service. You can now define a matcher to define rules for the correctness of a call.

Assertions in IBS will allow you to reference different calls you have previously made in the "callContent" section. Just as in argument epansion, we will fetch the result of the call and use in the assertion.

An assertion, in its most basic form, can be done in the following way:

{
  "callContent": {
    "<ID>": {
      "class": "<package name>.<class Name>",
      "method": "<method name>",
      "args": [
        "argument1",
        "argument2"
      ]
    }
  },
  "assertions": {
    "<Assertion Title>": {
      "matcher": "<A matcher defined in the org.hamcrest.Matchers class>",
      "actualValue": "<ID> as referenced in the call value. or a simple value",
      "expectedValue": "A value or an ID"
    }
  }
}

The assertions will then be present in the return payload:

{
  "returnValues": {
    "<ID>": "<result>"
  },
  "callDurations": {
    "<ID>": "<duration ms>"
  },
  "assetions": {
    "<Assertion Title>": "<true or false>"
  }
}

example:

{
  "callContent": {
    "fetchString1": {
      "class": "com.adobe.campaign.tests.bridge.testdata.one.SimpleStaticMethods",
      "method": "methodReturningString"
    },
    "fetchString2": {
      "class": "com.adobe.campaign.tests.bridge.testdata.one.SimpleStaticMethods",
      "method": "methodReturningString"
    }
  },
  "assertions": {
    "Both values should be the same": {
      "matcher": "equalTo",
      "actualValue": "fetchString1",
      "expectedValue": "fetchString2"
    }
  }
}

By default, assertions in the Bridge Service will look at the resulut of a call, however, you can chose a different behavior or this. Currently, assertions are of two types:

Result Based,
Duration Based

Duration-Based Assertions

As mentioned earlier an assertion can be duration based. In that case, IBS will consider the call duration of a call for the assertion. In order to perform an assertion the payload needs to include the entry "type": "DURATION" to the payload:

{
  "callContent": {
    "<ID>": {
      "class": "<package name>.<class Name>",
      "method": "<method name>",
      "args": [
        "argument1",
        "argument2"
      ]
    }
  },
  "assertions": {
    "<Assertion Title>": {
      "type": "DURATION",
      "matcher": "<A matcher defined in the org.hamcrest.Matchers class>",
      "actualValue": "<ID>",
      "expectedValue": "Expected duration for ID in milli-seconds"
    }
  }
}

When set, the assertion will use the call duration of the call, and use it in the assertion evaluation.

Example:

{
  "callContent": {
    "spendTime": {
      "class": "com.adobe.campaign.tests.bridge.testdata.one.SimpleStaticMethods",
      "method": "methodWithTimeOut",
      "args": [
        100
      ]
    }
  },
  "assertions": {
    "The duration should not be greater than 100": {
      "type": "DURATION",
      "matcher": "greaterThanOrEqualTo",
      "actualValue": "spendTime",
      "expectedValue": "100"
    }
  }
}

Error Management

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

Contributing to the Project

There are two main docs for contributing:

The Contributing Doc For general contribution rules.
The Technical Doc For general technical aspects.

Known Errors

Linked Error

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.

Known Issues and Limitations

As this is a new project there are a few limitations to our solution:

Cannot call overloaded methods with the same number of arguments.

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>.

Only simple arguments

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.

Complex Non-Serializable Return Objects

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.

The mining or "scraping" is done by calling all the visible getters of the object. This can be nested, with a limit of three levels. You can modify this by setting the environment variable IBS.DESERIALIZATION.DEPTH.LIMIT.

Calling Enum Methods

We are currently unable to call enums with the Bridge Service.

adobe / bridgeService

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