Better error messaging with vectordb procedures

[vga91]

The following procedure should return the root cause (i.e. the collection already exists):

Procedure errors to handle and improve:

• apoc.vectordb..createCollection with existing collection
• apoc.vectordb..deleteCollection with non existing collection
• apoc.vectordb..get/upsert/delete with wrong format id
• apoc.vectordb..upsert/query with wrong embedding size

[vga91]

Currently, it does not seem possible to solve the issue by acting on APOC Extended, it would be necessary to modify APOC Core.

The following solution (i.e. the one provided in the internal APOC core Trello with id G2oExgfb) would solve the issue:

// placed in StreamCollection.UrlStreamConnection class by replacing the present method

        @Override
        public InputStream getInputStream() throws IOException {
            if (con instanceof HttpURLConnection httpConn && httpConn.getResponseCode() >= 400)
            {
                // return ErrorStream as a RuntimeException
                String errMsg = new String(httpConn.getErrorStream().readAllBytes());
                throw new RuntimeException("Error during HTTP call:\n" + errMsg);
            }

            return toLimitedIStream(con.getInputStream(), getLength());
        }

By returning the following output in case of an existing collection:

org.neo4j.graphdb.QueryExecutionException:
Failed to invoke procedure `apoc.vectordb.weaviate.createCollection`: Caused by: java.lang.RuntimeException: Error during HTTP call:
{"error":[{"message":"class name \"TestCollection\" already exists"}]}

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Examples of test case to update after the above fixes: https://github.com/neo4j-contrib/neo4j-apoc-procedures/commit/99e6025f9a2462d39f48637c42b3cb60647f9441