experimental: SAP documentation

docs/guides/sap/btp-integration.md

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+---
+id: btp-integration
+title: SAP BTP integration
+description: "Learn about the Camunda SAP Business Technology Platform (BTP) integration, an artifact run on BTP."
+---
+
+The Camunda SAP Business Technology Platform (BTP) integration is an artifact run on BTP. This connects to Camunda 8 SaaS to achieve the following:
+
+- Provides a generic Fiori app for starting BPMN processes and displaying Camunda Forms in the Fiori design language.
+- Exposes selected BTP services to BPMN tasks and vice versa.
+- Provides a generic endpoint to start BPMN processes with.
+
+:::note Important!
+The BTP integration is an alpha feature available upon request. Visit [https://camunda.com/contact](https://camunda.com/contact) to contact us.
+:::

docs/guides/sap/camunda-sap-integration.md

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+---
+id: sap-integration
+title: SAP integration
+description: "Set up your Camunda 8 account to get started."
+---
+
+Camunda's SAP integration consists of several features that can be used independently of one another: SAP OData, RFC, and BTP.
+
+- [SAP OData outbound Connector](./odata-connector.md): interact with an S/4HANA or ECC System via OData v2 + v4 APIs, directly from your BPMN model.
+- [SAP RFC outbound Connector](./rfc-connector.md): Query BAPIs and remote-enabled function modules on SAP ECC systems.
+- [SAP BTP integration](./btp-integration.md)
+  - Use Tasklist's forms as Fiori UI
+  - Operate BTP services from BPMN tasks
+  - Inbound proxy endpoint to start process instances of BPMN models, including custom variables
+
+These features run in the customer's scope on [https://www.sap.com/products/technology-platform.html](https://www.sap.com/products/technology-platform.html). They do not require a proprietary Camunda-related setup, and instead re-use an existing infrastructure with minimal prerequisites. This shared resource usage is cost-effective and aids both your and Camunda's sustainability effort.
+
+![SAP integration overview](./img/sap-integration-overview.png)

docs/guides/sap/odata-connector.md

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+---
+id: odata-connector
+title: SAP OData Connector
+description: "The SAP OData Connector is a protocol and outbound Connector that runs as a Docker image on the SAP Business Technology Platform (BTP)."
+---
+
+The SAP OData Connector is a protocol and outbound [Connector](/components/connectors/introduction.md) that runs as a Docker image on the SAP Business Technology Platform (BTP).
+
+This Connector is designed to run in [hybrid mode](/guides/use-connectors-in-hybrid-mode.md), living in the customer's BTP sub-account in the Cloud Foundry environment.
+
+This Connector works with Camunda 8 SaaS, and utilizes BTP's [Destination](https://learning.sap.com/learning-journeys/administrating-sap-business-technology-platform/using-destinations) and [Connectivity](https://help.sap.com/docs/connectivity/sap-btp-connectivity-cf/what-is-sap-btp-connectivity) concepts to query a SAP system via both OData v2 and v4.
+
+:::note Important!
+This Connector is an alpha feature and available upon request. Visit [https://camunda.com/contact](https://camunda.com/contact) to contact us.
+:::
+
+## Quickstart
+
+For a standard overview of the steps involved in the SAP OData Connector, examine the diagram below:
+
+![OData steps](./img/odata-steps.png)
+
+## Prerequisites
+
+This Connector integrates into a standard BTP landscape and doesn't require any proprietary setup.
+
+However, a minimum set of SAP infrastructure requirements must be in place for the SAP OData Connector Docker image to run:
+
+- [Cloud Foundry CLI](https://github.com/cloudfoundry/cli) with [multiapps plugin](https://github.com/cloudfoundry/multiapps-cli-plugin) installed on the machine doing the deployment.
+- BTP subaccount with a [Cloud Foundry environment](https://discovery-center.cloud.sap/serviceCatalog/cloud-foundry-runtime?region=all) enabled and a [space created](https://help.sap.com/docs/btp/sap-business-technology-platform/create-spaces).
+- Minimum of [1GB storage quota, 2 GB runtime memory](https://help.sap.com/docs/btp/sap-business-technology-platform/managing-space-quota-plans).
+- [Entitlements](https://help.sap.com/docs/btp/sap-business-technology-platform/managing-entitlements-and-quotas-using-cockpit) for:
+  - [Connectivity Service](https://discovery-center.cloud.sap/serviceCatalog/connectivity-service?region=all), `lite` plan (to connect to the SAP is on-premises)
+  - [Destination Service](https://discovery-center.cloud.sap/serviceCatalog/destination?service_plan=lite&region=all&commercialModel=btpea), `lite` plan
+- One or more instance- or subaccount-level destinations, pointing to the SAP systems to communicate with.
+  ![sample BTP destination configuration](/Users/volker.buzek/git/camunda/camunda-docs/docs/guides/sap/images/btp-destination.png)
+
+:::warning
+Ensure `Additional Properties` are correctly set on the Destination.
+
+Here's a recommended set of properties:
+
+```json
+HTML5.DynamicDestination: true
+sap-client: <client/"Mandant" to work with on the SAP system>
+WebIDEEnabled: true
+WebIDESystem: <SAP system ID>
+WebIDEUsage: odata_gen
+```
+
+:::
+
+:::warning
+Currently, only `BasicAuthentication` is supported on the Destination by the SAP OData Connector.
+:::
+
+## Deployment to BTP
+
+A descriptor file is all that's required to deploy the SAP OData Connector to a space in a BTP subaccount. An exemplary deployment descriptor `mtad.yaml.example` is provided by Camunda. This is a standard format in BTP's Cloud Foundry environment to describe the application that needs deployment.
+
+Adjust the values to match those of the targeted Camunda 8 SaaS environment and rename it to `mtad.yaml`.
+
+Adjust the names of the BTP destination- and connectivity-instances to your liking - both will be created automatically for you upon deployment. If instances in your subaccount of any of the two services exist, they will not be replaced, but reused.
+
+After creating the `mtad.yaml` file, log into the desired BTP subaccount via the [Cloud Foundry `cli`](https://github.com/cloudfoundry/cli) (cf-cli):
+
+```shell
+$> cf login
+API endpoint: https://api.cf. ...
+...
+```
+
+Then, deploy the SAP OData Connector via the `cf-cli`. Note that this requires [the "multiapps" plugin of Cloud Foundry](https://github.com/cloudfoundry/multiapps-cli-plugin) to be installed on the machine the deployment runs on.
+
+```shell
+$> cf deploy ./ # append the -f flag to shortcircuit ongoing deployments
+Deploying multi-target app archive /Some/path/sap-odata-connector.mtar in org <your-org> / space <your-space> as [email protected] ..
+...
+Application "sap-odata-connector" started and available at "some.url.hana.ondemand.com"
+```
+
+## Deployment in Camunda 8 SaaS
+
+If using Web Modeler, [import the SAP OData Connector's element template](/components/connectors/manage-connector-templates.md#importing-existing-connector-templates) for design use.
+
+![sample BPMN diagram with SAP OData connector](./img/sap-odata-connector-task-in-model.png)
+
+If using Desktop Modeler, [follow the standard importing procedure](/components/modeler/desktop-modeler/element-templates/configuring-templates.md).
+
+## Working with the SAP OData Connector in Camunda Modeler
+
+### Modeling options
+
+Modeling the SAP OData Connector task is similar to any other Camunda Connector. When the BPMN task is selected, the properties panel in Modeler shows the respective options.
+
+:::note
+The configuration options will dynamically change with the selected HTTP method and the OData protocol version. For example, a `payload` field is only displayed when the HTTP method is other than "GET".
+:::
+
+![SAP OData connector element template](./img/sap-odata-connector-element-template.png)
+
+Specifying the `BTP destination name` allows for re-using existing Destinations from the subaccount or instance level. Authentication and authorizations are maintained at that level, and that is why it's not necessary to maintain credentials for the Connector.
+
+:::note
+Currently, only `BasicAuthentication` is supported on the Destination by the SAP OData Connector.
+:::
+
+### Advanced capabilities
+
+In addition to the basic OData settings such as Service, Entity, or EntitySet, method, and OData version, the **Advanced** section allows you to fine tune `GET` queries to the SAP method with all standard parameters. For example, supplying `$filter` and `$select` parameters help in reducing data transferred over the wire, while `$expand` helps in retrieving additional entities with a single query.
+
+![Advanced options of the SAP OData connector element template](./img/sap-odata-connector-element-template-advanced.png)
+
+### Query result structure
+
+The result of any query, be it reading or writing to the SAP system, is in JSON format and holds the following structure:
+
+```json
+{
+  result: <further json>,
+  statusCode: <http status code>,
+  countOrInlineCount: <integer, optional!>
+}
+```
+
+- `result` contains the result of the query, whether it is content retrieved from a SAP system via `GET` or the result of a write or update operation via `POST`, `PUT`, `PATCH`, or `DELETE`. (Note that with the latter, the `result` is always empty.)
+- `statusCode` holds the [HTTP status code](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status) of the operation.
+- `countOrInlineCount` is only present in the response when the corresponding option `$inlinecount` (for OData v2) or `$count` (for OData v4) was checked in the design time of the BPMN task. It then shows the number of results from `GET` query to the SAP system.
+
+![the output mapping of the SAP OData element template](./img/sap-odata-connector-element-template-result.png)
+
+The query result can either be mapped to a single result variable or worked on [via FEEL with an expression](https://docs.camunda.io/docs/next/components/connectors/use-connectors/#result-expression). The same is applicable to `getResponse` as a result variable contains the described query JSON in its entirety, as to what the result expression `{getStatusCode: statusCode}` would only hold the HTTP status code in the `getStatusCode` process variable.
+
+### Error handling
+
+The SAP OData Connector allows handling of query errors directly in the model. This means an OData error is relayed to the process instance in the reserved variables `bpmnError` and `error` and can be processed accordingly.
+
+Equip the Connector task with an error handling expression such as:
+
+```js
+if error.code = "400" then
+  bpmnError("400", "client request is bad", { errorMessage: error.message, errorCode: error.code })
+else if error.code = "404" then
+  bpmnError("404", "queried resource not found", { errorMessage: error.message, errorCode: error.code })
+else if error.code = "500" then
+  bpmnError("500", "server error", { errorMessage: error.message, errorCode: error.code })
+else if error.code = "503" then
+  bpmnError("503", "I'm just an proxy teapot", { errorMessage: error.message, errorCode: error.code })
+else
+  null
+```
+
+![image-20241010160419616](./img/odata-connector-error-expression.png)
+
+Specifically note the third parameter to `bpmnError`:
+
+```js
+{ errorMessage: error.message, errorCode: error.code }
+```
+
+This relays the error message and code to the next step in the process flow.
+
+Then, equip the BPMN task with an error boundary event:
+
+![error boundary event on SAP OData connector](./img/sap-odata-connector-task-error-handling2.png)
+
+If the SAP OData Connector encounters an error, the boundary event will catch the error and continue the process flow. The error boundary event can receive these configuration parameters to contain further error details:
+
+![error output mapping](./img/sap-odata-connector-task-error-handling1.png)
+
+- `errorMessage` contains a verbose version of the error message and cause and relays it into the process scope as `ov_errorMessage`.
+- `errorCode` holds a predefined value describing the scope of the error, relaying it to the process scope as `errorCode`.
+  It can be one of the following:
+  - `INVALID_PAYLOAD`: The payload of the request was detected as erroneous by the server.
+  - `REQUEST_ERROR`: The request contained an error, efor example, a wrong combination of `GET` query parameters.
+  - `GENERIC_ERROR`
+  - `DESTINATION_ERROR`: An error occurred while claiming the Destination from the runtime environment.
+- `error` is the serialized Error object, available in the example above as `ov_error`.
+
+## Tips
+
+- Ensure the connection from the Cloud Foundry environment via the destination to the SAP systems works. Using the [Terminal in Business Application Studio](https://community.sap.com/t5/technology-blogs-by-sap/how-to-check-the-connectivity-to-your-backend-system-in-business/ba-p/13479832) is a quick way to verify this.
+- Validate requests first in an API client before trying with the SAP OData connector in Modeler. Then, copy over to the element template fields. This saves time and reduces potential error sources.
+- Any payload size <= 2.5MB can be considered safe.