Content
# BridgeService
[](https://github.com/adobe/bridgeService/actions/workflows/onPushSimpleTest.yml)
[](https://codecov.io/gh/adobe/bridgeService)
[](https://javadoc.io/doc/com.adobe.campaign.tests.bridge.service/integroBridgeService)
[](https://sonarcloud.io/summary/new_code?id=adobe_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.
## Table of Contents
<!-- TOC -->
- [BridgeService](#bridgeservice)
- [Table of Contents](#table-of-contents)
- [Background](#background)
- [Demo Project](#demo-project)
- [Release Notes](#release-notes)
- [Implementing The Bridge Service in Your Project](#implementing-the-bridge-service-in-your-project)
- [Adding the Bridge Service to Your Project](#adding-the-bridge-service-to-your-project)
- [Installation](#installation)
- [Considerations](#considerations)
- [Including your project in the BridgeService](#including-your-project-in-the-bridgeservice)
- [Java Version Compatibility](#java-version-compatibility)
- [Starting the Bridge Service](#starting-the-bridge-service)
- [Running the Bridge Locally](#running-the-bridge-locally)
- [Running a DEMO](#running-a-demo)
- [Setting Information About your Environment](#setting-information-about-your-environment)
- [Testing That all is Working](#testing-that-all-is-working)
- [Testing That all External Devices can be Accessed](#testing-that-all-external-devices-can-be-accessed)
- [Making Java Calls](#making-java-calls)
- [A basic Java Call](#a-basic-java-call)
- [Instantiating Objects](#instantiating-objects)
- [Call Chaining a basic Java Call](#call-chaining-a-basic-java-call)
- [Call Chaining and Call Dependencies](#call-chaining-and-call-dependencies)
- [Call Chaining and Instance Methods](#call-chaining-and-instance-methods)
- [Argument Types](#argument-types)
- [Simple Java Objects](#simple-java-objects)
- [Lists and Arrays](#lists-and-arrays)
- [Complex Types](#complex-types)
- [Files](#files)
- [Results](#results)
- [Formatting Dates](#formatting-dates)
- [Deserialization Plugins](#deserialization-plugins)
- [Managing Timeouts](#managing-timeouts)
- [Setting Timeout Globally](#setting-timeout-globally)
- [Setting a Timeout for the Call Session](#setting-a-timeout-for-the-call-session)
- [Creating a Call Context](#creating-a-call-context)
- [Static Variable Scopes](#static-variable-scopes)
- [Session Scopes](#session-scopes)
- [Product Scope](#product-scope)
- [Headers and Secrets](#headers-and-secrets)
- [Secrets](#secrets)
- [Steamlining Headers](#steamlining-headers)
- [Making Assertions](#making-assertions)
- [Duration-Based Assertions](#duration-based-assertions)
- [Using BridgeService as an MCP Server](#using-bridgeservice-as-an-mcp-server)
- [Enabling MCP](#enabling-mcp)
- [Discovering Tools](#discovering-tools-toolslist)
- [Calling a Discovered Tool](#calling-a-discovered-tool-toolscall)
- [The java_call Tool](#the-java_call-tool)
- [Diagnostics](#diagnostics-ibs_diagnostics)
- [MCP Configuration](#mcp-configuration)
- [MCP Limitations](#mcp-limitations)
- [Error Management](#error-management)
- [Contributing to the Project](#contributing-to-the-project)
- [Known Errors](#known-errors)
- [Linked Error](#linked-error)
- [Known Issues and Limitations](#known-issues-and-limitations)
_ [Cannot call overloaded methods with the same number of arguments.](#cannot-call-overloaded-methods-with-the-same-number-of-arguments)
_ [Only simple arguments](#only-simple-arguments)
_ [Complex Non-Serializable Return Objects](#complex-non-serializable-return-objects)
_ [Calling Enum Methods](#calling-enum-methods)
<!-- TOC -->
## 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](https://github.com/adobe/test-as-a-product-demo).
## Release Notes
The release notes can be found [here](ReleaseNotes.md).
## 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.
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>3.11.5</version>
</dependency>
```
#### Considerations
Since the BridgeService uses Jetty (via Javalin 6) it is quite possible that there may be conflicts in the project when
you add this library. BridgeService 3.11.3+ uses the `jakarta.servlet` namespace (Jetty 11). If your project still uses
`javax.servlet`, you will need to migrate to `jakarta.servlet` or ensure the two are isolated on the classpath.
### Including your project in the BridgeService
In this model you can simply add your project as a dependency to the BridgeProject.
### Java Version Compatibility
Legend: ✅ Works | ⚠️ Works with workarounds | ❌ Fails
**Injection Model** — the exposed project's JVM loads IBS. Both IBS bytecode and the HTTP framework must be compatible with that JVM.
| IBS release | Exposed Java 8 | Exposed Java 11 | Exposed Java 17 | Exposed Java 21 |
| ------------------------------ | :------------: | :-------------: | :-------------: | :-------------: |
| **pre-3.11.3** (Spark, Java 11) | ❌ ¹ | ✅ | ⚠️ ² | ❌ ³ |
| **3.11.3+** (Javalin 6, Java 11) | ❌ ¹ | ✅ | ✅ | ✅ |
**Aggregator Model** — IBS runs its own JVM and loads the exposed project's classes via reflection.
| IBS release | Exposed Java 8 | Exposed Java 11 | Exposed Java 17 | Exposed Java 21 |
| ------------------------------ | :------------: | :-------------: | :-------------: | :-------------: |
| **pre-3.11.3** (Spark, Java 11) | ✅ | ✅ | ❌ ⁴ | ❌ ⁴ |
| **3.11.3+** (Javalin 6, Java 11) | ✅ | ✅ | ❌ ⁴ | ❌ ⁴ |
¹ Exposed project JVM cannot load IBS bytecode — `UnsupportedClassVersionError`.
² Spark is unofficial on Java 17 and requires `--add-opens` flags.
³ Spark is not compatible with Java 21.
⁴ IBS JVM (Java 11) cannot load class files compiled to Java 17+ — `UnsupportedClassVersionError` in the class loader.
For the full analysis and the planned Java 21 upgrade (issue #39), see [docs/JavaMigration.md](docs/JavaMigration.md).
## 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 with a built-in demo project (`bridgeService-data`) in Aggregator mode. Start it with:
```bash
mvn -pl integroBridgeService exec:java -Dexec.args="test" \
-Ddemo.project.mode=compile \
-DIBS.MCP.ENABLED=true \
-DIBS.CLASSLOADER.STATIC.INTEGRITY.PACKAGES=com.adobe.campaign.tests.bridge.testdata
```
This starts BridgeService on `http://localhost:8080` and exposes the demo classes from `com.adobe.campaign.tests.bridge.testdata.*` as both REST endpoints and MCP tools.
For MCP usage, configure your AI client to point at `http://localhost:8080/mcp` — see [docs/MCP.md](docs/MCP.md) for client-specific setup.
#### Use case 1 — Call a method with a string argument
**REST** (`POST /call`):
```json
{
"callContent": {
"result": {
"class": "com.adobe.campaign.tests.bridge.testdata.one.SimpleStaticMethods",
"method": "methodAcceptingStringArgument",
"args": ["world"]
}
}
}
```
**MCP**: *"Call the method that accepts a string argument and pass 'world' to it"*
**Response**: `{"returnValues":{"result":"world_Success"}}`
---
#### Use case 2 — Call a method returning a list
**REST** (`POST /call`):
```json
{
"callContent": {
"countries": {
"class": "com.adobe.campaign.tests.bridge.testdata.one.ClassWithLogger",
"method": "getCountries"
}
}
}
```
**MCP**: *"Get the list of available countries"*
**Response**: `{"returnValues":{"countries":["AT","AU","CA","CH","DE"]}}`
---
#### Use case 3 — Call chaining
**REST** (`POST /call`):
```json
{
"callContent": {
"country": {
"class": "com.adobe.campaign.tests.bridge.testdata.one.ClassWithLogger",
"method": "fetchRandomCountry"
},
"result": {
"class": "com.adobe.campaign.tests.bridge.testdata.one.SimpleStaticMethods",
"method": "methodAcceptingStringArgument",
"args": ["country"]
}
}
}
```
**MCP**: *"Get a random country and pass it as an argument to methodAcceptingStringArgument"*
**Response**: `{"returnValues":{"country":"AU","result":"AU_Success"}}` *(country is random)*
## 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 : 3.11.5
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:
```JSON
{
"<URL ID 1>": "<dns 1>:<Port>",
"<URL ID 2>": "<dns 2>:<Port>"
}
```
The payload returns a JSON with the test results:
```JSON
{
"<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`
```JSON
{
"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.
```JSON
{
"returnValues": {
"<ID>": "<result>"
},
"callDurations": {
"<ID>": "<duration ms>"
}
}
```
Here is an example for the POST call `http://localhost:8080/call` and the payload:
```JSON
{
"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:
```JSON
{
"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:
```JSON
{
"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:
```JSON
{
"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:
```JSON
{
"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:
```JSON
{
"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:
```JSON
{
"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:
```JSON
{
"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.
```JSON
{
"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.
```shell
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:
```JSON
{
"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](#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](https://docs.oracle.com/javase/8/docs/api/java/text/SimpleDateFormat.html). 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.
```JSON
{
"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.
```JSON
{
"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](./docs/Technical.md#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:
```shell
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 `args`section. The call will return :
```JSON
{
"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:
```shell
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:
```JSON
{
"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.
### Environment Variables via Headers
Headers prefixed with `ibs-env-` are injected as environment variables into the Java execution context — equivalent
to supplying them in the `environmentVariables` JSON node, but without modifying the payload. The prefix is stripped
and the remainder uppercased to form the variable name.
Example — pass a hostname and a locale without touching the payload:
```shell
curl --request POST \
--url http://localhost:8080/call \
--header 'Content-Type: application/json' \
--header 'ibs-env-AC.UITEST.HOST: my-instance.example.com' \
--header 'ibs-env-AC.UITEST.LANGUAGE: en_US' \
--data '{
"callContent": {
"result": {
"class": "com.example.MyService",
"method": "run",
"args": []
}
}
}'
```
IBS injects `AC.UITEST.HOST=my-instance.example.com` and `AC.UITEST.LANGUAGE=en_US` before the call executes.
The prefix can be changed via `IBS.ENV.HEADER.PREFIX` or set to blank to disable the feature entirely.
Env-var headers are distinct from regular headers: they are not stored in the call-chain resolution cache and
cannot be referenced in `args`.
### 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`. Secret headers (`ibs-secret-*`) and env-var
headers (`ibs-env-*`) are always handled by their own mechanisms and are not affected by this filter.
## 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](https://hamcrest.org/JavaHamcrest/javadoc/2.2/org/hamcrest/Matchers.html) 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:
```JSON
{
"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:
```JSON
{
"returnValues": {
"<ID>": "<result>"
},
"callDurations": {
"<ID>": "<duration ms>"
},
"assetions": {
"<Assertion Title>": "<true or false>"
}
}
```
example:
```JSON
{
"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:
```JSON
{
"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:
```JSON
{
"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"
}
}
}
```
## Using BridgeService as an MCP Server
BridgeService can act as an [MCP (Model Context Protocol)](https://modelcontextprotocol.io/) server, allowing AI agents to discover and invoke your Java methods as typed tools over HTTP. The MCP endpoint uses JSON-RPC 2.0 and is served on the **same port** as the existing REST API.
For full configuration details, advanced usage, and integration with Claude Code and Cursor, see [docs/MCP.md](docs/MCP.md).
### Enabling MCP
Set the environment variable `IBS.MCP.ENABLED` to `true` before starting BridgeService:
```bash
mvn exec:java -Dexec.args="test" -DIBS.MCP.ENABLED=true -DIBS.CLASSLOADER.STATIC.INTEGRITY.PACKAGES=com.example.mypackage
```
At startup, BridgeService scans the packages listed in `IBS.CLASSLOADER.STATIC.INTEGRITY.PACKAGES` and builds a **method catalog** from every **public static method** found. Each discovered method is exposed as its own named MCP tool in `tools/list`. A generic `java_call` tool is always present for multi-step chains and instance method calls.
The MCP endpoint is available at:
```
POST /mcp
```
An MCP client begins with the standard handshake:
```json
{
"jsonrpc": "2.0",
"id": 1,
"method": "initialize",
"params": {
"protocolVersion": "2024-11-05",
"clientInfo": { "name": "my-client", "version": "1.0" },
"capabilities": {}
}
}
```
Response:
```json
{
"jsonrpc": "2.0",
"id": 1,
"result": {
"protocolVersion": "2024-11-05",
"serverInfo": { "name": "bridgeService", "version": "3.11.5" },
"capabilities": { "tools": {} }
}
}
```
### Discovering Tools (tools/list)
`tools/list` returns **one tool per auto-discovered method** plus `java_call` (for multi-step chains) and `ibs_diagnostics`. Tools are named `{SimpleClassName}_{methodName}` and carry their own `inputSchema` and Javadoc-sourced description.
```json
{
"jsonrpc": "2.0",
"id": 2,
"method": "tools/list",
"params": {}
}
```
Response (abbreviated):
```json
{
"jsonrpc": "2.0",
"id": 2,
"result": {
"tools": [
{
"name": "SimpleStaticMethods_methodAcceptingStringArgument",
"description": "Appends the success suffix to the given string.",
"inputSchema": {
"type": "object",
"properties": {
"arg0": { "type": "string", "description": "the input string" }
},
"required": ["arg0"]
}
},
{
"name": "java_call",
"description": "Generic BridgeService call for multi-step chains. ...",
"inputSchema": { "...": "..." }
},
{
"name": "ibs_diagnostics",
"description": "Built-in IBS diagnostic tool. ...",
"inputSchema": { "type": "object", "properties": {} }
}
]
}
}
```
See [docs/MCP.md](docs/MCP.md) for the full tool format and method discovery details.
### Calling a Discovered Tool (tools/call)
Single-method calls can be made directly by tool name. Pass arguments as flat key-value pairs matching the `inputSchema`:
```json
{
"jsonrpc": "2.0",
"id": 3,
"method": "tools/call",
"params": {
"name": "SimpleStaticMethods_methodAcceptingStringArgument",
"arguments": { "arg0": "hello" }
}
}
```
On success the result contains the standard BridgeService return payload serialised as text:
```json
{
"jsonrpc": "2.0",
"id": 3,
"result": {
"content": [
{
"type": "text",
"text": "{\"returnValues\":{\"result\":\"hello_Success\"},\"callDurations\":{\"result\":3}}"
}
],
"isError": false
}
}
```
If the method throws an exception, `isError` is `true` and `content[0].text` contains the error description. The HTTP status code is always `200` for `tools/call` — errors are reported inside the MCP result, not as HTTP errors.
**When to use individual tools vs `java_call`:**
| Scenario | Use |
| ----------------------------------------------- | ---------------------------------------- |
| Single stateless read | Individual tool (`ClassName_methodName`) |
| Step B needs the Java object returned by step A | `java_call` with call chain |
| Overloaded method (same parameter count) | `java_call` |
| Instance method or constructor | `java_call` |
### The `java_call` Tool
`java_call` accepts the same payload as the standard `POST /call` endpoint, making call chaining, instance methods, environment variables, and file uploads all accessible to MCP clients. **Bundle all related operations into a single `java_call`** using call chaining — static variable state (including authentication) does not persist between separate tool calls.
### Diagnostics (`ibs_diagnostics`)
A built-in `ibs_diagnostics` tool is always available alongside `java_call`. It requires no arguments and reports the running IBS version, MCP configuration state, received headers, and the number of methods in the catalog — useful for verifying a new server connection without touching HOST code.
### MCP Configuration
| Variable | Default | Description |
| ------------------------- | ------- | ----------------------------------------------------------------------------------- |
| `IBS.MCP.ENABLED` | `false` | Enables the MCP endpoint at `/mcp` |
| `IBS.MCP.PRECHAIN` | — | `callContent` fragment prepended to every `java_call` invocation (e.g. shared auth) |
| `IBS.MCP.REQUIRE_JAVADOC` | `true` | When `true`, only methods with a Javadoc comment are included in the catalog |
### MCP Limitations
- Only **public static methods** are auto-discovered. Instance methods are accessible via `java_call`.
- Overloaded methods with the **same number of parameters** are skipped during discovery. Use `java_call` to call them explicitly.
- Parameter names are exposed as `arg0`, `arg1`, … — Java reflection does not retain source-level parameter names at runtime.
## 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:
```json
{
"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:
```JSON
{
"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](CONTRIBUTING.md) For general contribution rules.
- [The Technical Doc](docs/Technical.md) 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.
