GitHub user FrancescoCastaldi added a comment to the discussion: Database connection: proxy in front of solr
The error `ERROR: Expecting value: line 1 column 1 (char 0)` is a Python `json.decoder.JSONDecodeError`. It occurs when `solr-sqlalchemy` sends an HTTP request expecting a JSON response from Solr, but the server (in this case, Knox Gateway) returns an HTML document or an empty response (such as an HTTP 401/403 authentication challenge or an HTML login redirect). Between modifying `solr-sqlalchemy` for Kerberos vs Knox Gateway, using Knox Gateway is by far the cleaner and standard approach because Knox is explicitly designed to handle the Kerberos/SPNEGO authentication on the Hadoop/Solr side while offering simple HTTP Basic Auth to external clients like Superset. Here is how to resolve the connection through Knox: ### 1. Fix the Knox Gateway URL Path Structure Apache Knox topologies expose services under `/gateway/<topology_name>/<service_name>`. Your connection URI should include the `/gateway/` path prefix: ```text solr://username:[email protected]:443/gateway/europe-italy/team-tiramisu/solr/cheese_collection ``` If your Knox topology is mapped with SSL on port 443, ensure `use_ssl=true` is passed so requests use `https://` instead of `http://`. ### 2. Configure Engine Parameters and SSL Verification in Superset In Superset, go to **Settings -> Database Connections -> Edit -> Advanced -> Other**, and configure the **Engine Parameters** with proper HTTP headers and SSL certificates: ```json { "connect_args": { "scheme": "https", "verify_ssl": true } } ``` ### 3. Verify the Knox Endpoint Directly via cURL Before testing in Superset, verify from the Superset server shell that Knox is accepting your Basic Auth credentials and returning valid Solr JSON: ```bash curl -k -u "username:password" \ "https://my.knox.vip.com:443/gateway/europe-italy/team-tiramisu/solr/cheese_collection/select?q=*:*&wt=json"; ``` If this returns an HTML page containing "Knox Authentication Failed" or a 302 redirect, check your Knox service role permissions for the `solr` service in that topology. Once cURL returns a raw JSON object starting with `{ "responseHeader": ... }`, the SQLAlchemy Solr driver will connect successfully. GitHub link: https://github.com/apache/superset/discussions/40727#discussioncomment-19164774 ---- This is an automatically sent email for [email protected]. To unsubscribe, please send an email to: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
