[GitHub] couchdb-fabric issue #86: Return Error When Workers Crash

[nickva <gi...@git.apache.org>]

Github user nickva commented on the issue:

    https://github.com/apache/couchdb-fabric/pull/86
  
    Created a 5 nodes clusters with `./dev/run -n5` that did not go smoothly and had to tweak it by hand some. Somehow ended up with a 'couchdb@127.0.0.1' node in mem3:nodes() instead of node4 and node5.
    
    Then created a `<<"db">>` and `<<"doc1">>` they ended up on nodes 2,3 and 4
    ```
    rp(mem3:shards(<<"db">>, <<"doc1">>)).
    [{shard,<<"shards/c0000000-dfffffff/db.1485801065">>,
            'node2@127.0.0.1',<<"db">>,
            [3221225472,3758096383],
            undefined},
     {shard,<<"shards/c0000000-dfffffff/db.1485801065">>,
            'node3@127.0.0.1',<<"db">>,
            [3221225472,3758096383],
            undefined},
     {shard,<<"shards/c0000000-dfffffff/db.1485801065">>,
            'node4@127.0.0.1',<<"db">>,
            [3221225472,3758096383],
            undefined}]
    ```
    
    Put all 3 nodes in maintenance and when querying via http got bad_match error
    
    ```
     $ http 'http://adm:pass@localhost:15984/db/doc1?open_revs=["1-967a00dff5e02add41819138abb3284d"]&latest=true&revs=true'
    HTTP/1.1 500 Internal Server Error
    
    {
        "error": "badmatch",
        "reason": "{error,all_workers_died}",
        "ref": 281556634
    }
    ```
    
    Just to compare *without* the fix I get:
    
    ```
    http  'http://adm:pass@localhost:15984/db/doc1?open_revs=["1-967a00dff5e02add41819138abb3284d"]&latest=true&revs=true' 'Accept:application/json'
    HTTP/1.1 200 OK
    
    []
    ```
     
    Also notice, we apparently also do handle `{ok, []}` result and return missing 404 but only if open_revs=all case:
    
    ```
            {ok, Results} = fabric:open_revs(Db, DocId, Revs, Options),
            case Results of
                [] when Revs == all ->
                    chttpd:send_error(Req, {not_found, missing});
    ```
    
    In https://github.com/cloudant/couchdb-chttpd/blob/master/src/chttpd_db.erl#L675


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