>I am inclined to go with the Teiid with Spring Boot approach, which will require redefining sources and views again in Java (probably Kotlin)

You do not need to redesign the views in JAVA but you can use your previous VDB. What you need to do run the migration utility in the Designer to generate XML based VDB, then convert from XML VDB to DDL based VDB

using https://github.com/teiid/teiid-openshift-examples#vdb-migration-utility

> I don't really know how I would go about maintaining/updating that vdb in the future.

Once you have the VDB in DDL, the idea is to directly manipulate the DDL to do any edits. This way you can even check in the VDB's DDL into source control systems like Git.

> I wanted to try out the Syndesis/Openshift approach, but since it requires a subscription I am not inclined to do that (also seems a bit overkill for my use case)

It is not a subscription, you can tryout on Minishift, but if your architecture is not towards cloud then yes you may be correct. But SpringBoot version is just a Java application works more or less like the WidlFly based VDB.

Once you have the VDB follow the example here teiid-spring-boot/samples/vdb at master · teiid/teiid-spring-boot · GitHub to take the VDB and create a Spring Boot based application. As part of this you need to create a data source for each of the sources you are using. This example shows a relational database, but there are examples for other types of data sources,

>Now, my biggest concern is on exposing the data. Is there another approach, other than ODATA v4?

No, all the previous methods of access from before are still preserved in Spring Boot port.

>Is it possible (without too much hassle) to expose the data using JDBC with Teiid with Spring Boot?

Yes, it is as simple as adding a property "teiid.jdbc-enable=true" in the application.properties file. However, by default, there is no security, if security is needed you need to plug in your own modules there. So, far we only added OAuth based security for OData V4 using Keycloak, we want to add Kerberos using the Keycloak too in coming versions.

Any issues let us know.

I suspect the initial move is going to be little cumbersome, but once you have the DDL (DDL VDB · GitBook) and working IMO it will be a lot more straight forward and easier development model than what we had with Designer/Wildfly based model. Note we follow a lot of SQL/MED semantics which is standard here. Another good thing is if your client is also written in Java, you embed this into the application in the single VM.

Yes, you can add spring security module, we just did not have an example for JDBC. The same is done for OData with keycloak. If you work out an example please consider contributing back.

Yes, the model of the program showin in the rest example [1] is based on using the Enity model, where as you are using the traditional VDB based mode as in example [2]. Both are valid, just that I do not have example redily available for the [2] example. With [2] you are not using annotaion model at to define your URLs. This would be good one to write next as document and showing different security profiles. Can you create documentation JIRA here [3] for this?

Basically you need to add (you may need latest master, as there may have been changes here to support better)

<dependency>

    <groupId>org.teiid</groupId>

    <artifactId>spring-data-rest</artifactId>

    <version>${version}</version>

</dependency>

to your pom.xml, then you can define a bean like "webCallBean" in the java code as in example [1] to define your connection to the source, where you get to define the RestTemplate in any Spring Boot application, where you can externalize the URL into configuration properties etc. However, when you use the VDB, write procedure as

" exec rest.springHttp(beanName)" as in "exec rest.springHttp('webCallBean')".

for example reading a json file is like

select ... from (exec rest.springHttp('webCallBean') ) as f, XMLTABLE('/' PASSING JSONTOXML ('response', f.result) COLUMNS ...) as x

basically the XMLTABLE part is exactly same as what you have in current VDB, just that exec part is different.

Another one is you can also use simply use as below. Note only difference from your previous VDB is changing "rest" prefix, everything else is same. Unfortunately here, I do not have a property replacement for URL, but that can easily added to replace any parts of the VDB. If you want you can add a JIRA for that too.

select ... from (exec rest.invokeHttp(action=>GET, enpoint=>'myurl') ) as f, XMLTABLE('/' PASSING JSONTOXML ('response', f.result) COLUMNS ...) as x

HTH

Ramesh..

[1] teiid-spring-boot/samples/rest at master · teiid/teiid-spring-boot · GitHub

[2] teiid-spring-boot/samples/vdb at master · teiid/teiid-spring-boot · GitHub

[3] Teiid Spring Boot - JBoss Issue Tracker

Looks like I do have an example here teiid-spring-boot/RestAsSource.adoc at master · teiid/teiid-spring-boot · GitHub

The above shows your own way to configure the rest endpoint.

How does VDB look like? Do you have these lines

CREATE SERVER oservice TYPE 'oservice' FOREIGN DATA WRAPPER rest;
CREATE SCHEMA myservice SERVER oservice;

Adding a new function will NOT work. What that tells me "rest" as translator is not registering. What is application.properties look like? The property for package scanning. Turn on debug and see if you see any class load errors.

Sorry, I wasn't thinking it through completely, and I had it as an error in my example. Do following

- Remove the property value for "spring.teiid.model.package" then it will scan entire classpath, then it will find it. You can add JIRA to take in multiple comma separated values for this property.

- Since we are working with VDB, we need to manually add a model for the 'rest' translator using the 'oservice' connection like below into DDL.

IMPORT FOREIGN SCHEMA "NONE" FROM SERVER oservice INTO myservice;

- Then use "myservice.invokeHttp" as the call on exec.

so in VDB should like

CREATE FOREIGN DATA WRAPPER rest;
CREATE SERVER oservice TYPE 'oservice' FOREIGN DATA WRAPPER rest;
CREATE SCHEMA myservice SERVER oservice;
IMPORT FOREIGN SCHEMA "NONE" FROM SERVER oservice INTO myservice;