如何使用 mogwai 执行 gremlin 查询

Posted 2023-02-23

【中文标题】如何使用 mogwai 执行 gremlin 查询

【英文标题】：How to execute gremlin query with mogwai

【发布时间】：2016-05-21 06:24:46

【问题描述】：

我试图通过 mogwai 查询 Titan db 0.5.4，但是当我运行以下脚本时出现错误：rexpro.exceptions.RexProScriptException: transaction is not open

我发现了同样的问题here

P.S mogwai 没有标签

脚本：

#!/usr/bin/env python3
from mogwai.connection import execute_query, setup


con = setup('127.0.0.1', graph_name="bio4j", username="re", password="re")

results = execute_query("2 * a",params="a":2, connection= con)
print(results)


results = execute_query("bio4j.E",params=, connection= con)
print(results)

日志：

$ ./bin/rexster.sh --start
0    [main] INFO  com.tinkerpop.rexster.Application  - .:Welcome to Rexster:.
93   [main] INFO  com.tinkerpop.rexster.server.RexsterProperties  - Using [/Users/Phoenix/Dropbox/Graph4Bio/Titan/rexhome/config/rexster.xml] as configuration source.
102  [main] INFO  com.tinkerpop.rexster.Application  - Rexster is watching [/Users/Phoenix/Dropbox/Graph4Bio/Titan/rexhome/config/rexster.xml] for change.
730  [main] INFO  com.thinkaurelius.titan.graphdb.configuration.GraphDatabaseConfiguration  - Generated unique-instance-id=0a69045d1736-AngryMac-local1
804  [main] INFO  com.thinkaurelius.titan.diskstorage.Backend  - Initiated backend operations thread pool of size 8
905  [main] INFO  com.thinkaurelius.titan.diskstorage.log.kcvs.KCVSLog  - Loaded unidentified ReadMarker start time Timepoint[1455128079919000 μs] into com.thinkaurelius.titan.diskstorage.log.kcvs.KCVSLog$MessagePuller@302c971f
908  [main] INFO  com.tinkerpop.rexster.RexsterApplicationGraph  - Graph [bio4j] - configured with allowable namespace [tp:gremlin]
932  [main] INFO  com.tinkerpop.rexster.config.GraphConfigurationContainer  - Graph bio4j - titangraph[berkeleyje:/Users/Phoenix/Dropbox/Graph4Bio/Bio4j/bio4j] loaded
939  [main] INFO  com.tinkerpop.rexster.server.metrics.HttpReporterConfig  - Configured HTTP Metric Reporter.
941  [main] INFO  com.tinkerpop.rexster.server.metrics.ConsoleReporterConfig  - Configured Console Metric Reporter.
2058 [main] INFO  com.tinkerpop.rexster.server.HttpRexsterServer  - HTTP/REST thread pool configuration: kernal[4 / 4] worker[8 / 8] 
2060 [main] INFO  com.tinkerpop.rexster.server.HttpRexsterServer  - Using org.glassfish.grizzly.strategies.LeaderFollowerNiostrategy IOStrategy for HTTP/REST.
2160 [main] INFO  com.tinkerpop.rexster.server.HttpRexsterServer  - Rexster Server running on: [http://localhost:8182]
2160 [main] INFO  com.tinkerpop.rexster.server.RexProRexsterServer  - Using org.glassfish.grizzly.strategies.LeaderFollowerNIOStrategy IOStrategy for RexPro.
2160 [main] INFO  com.tinkerpop.rexster.server.RexProRexsterServer  - RexPro thread pool configuration: kernal[4 / 4] worker[8 / 8] 
2162 [main] INFO  com.tinkerpop.rexster.server.RexProRexsterServer  - Rexster configured with [DefaultSecurity].
2163 [main] INFO  com.tinkerpop.rexster.server.RexProRexsterServer  - RexPro Server bound to [0.0.0.0:8184]
2177 [main] INFO  com.tinkerpop.rexster.server.ShutdownManager  - Bound shutdown socket to /127.0.0.1:8183. Starting listener thread for shutdown requests.
152568 [Grizzly(2) SelectorRunner] INFO  com.tinkerpop.rexster.protocol.EngineController  - ScriptEngineManager has factory for: ECMAScript
152568 [Grizzly(2) SelectorRunner] INFO  com.tinkerpop.rexster.protocol.EngineController  - ScriptEngineManager has factory for: gremlin-groovy
152568 [Grizzly(2) SelectorRunner] INFO  com.tinkerpop.rexster.protocol.EngineController  - Registered ScriptEngine for: gremlin-groovy
152569 [Grizzly(2) SelectorRunner] INFO  com.tinkerpop.rexster.protocol.EngineHolder  - Initializing gremlin-groovy engine with additional imports.
153259 [Grizzly(2) SelectorRunner] INFO  com.tinkerpop.rexster.protocol.EngineHolder  - ScriptEngine initializing with a custom script
154074 [Grizzly(2) SelectorRunner] INFO  com.tinkerpop.rexster.protocol.EngineController  - ScriptEngineManager has factory for: Groovy
154076 [Grizzly(2) SelectorRunner] INFO  com.tinkerpop.rexster.protocol.session.RexProSessions  - RexPro Session created: a2b416ce-75ea-4ecb-9835-b287162c90cb
154354 [Grizzly(4)] INFO  com.tinkerpop.rexster.protocol.session.RexProSessions  - Try to destroy RexPro Session: a2b416ce-75ea-4ecb-9835-b287162c90cb
154355 [Grizzly(4)] INFO  com.tinkerpop.rexster.protocol.session.RexProSessions  - RexPro Session destroyed or doesn't otherwise exist: a2b416ce-75ea-4ecb-9835-b287162c90cb
154356 [Grizzly(5)] INFO  com.tinkerpop.rexster.protocol.session.RexProSessions  - RexPro Session created: 5b8a669f-615d-4f84-9d1e-2d10624347f0
154525 [Grizzly(7)] WARN  com.tinkerpop.rexster.protocol.server.ScriptServer  - Could not process script [bio4j.E] for language [groovy] on session [[B@6634722f] and request [[B@68f38099]
154527 [Grizzly(8)] INFO  com.tinkerpop.rexster.protocol.session.RexProSessions  - Try to destroy RexPro Session: 5b8a669f-615d-4f84-9d1e-2d10624347f0
154527 [Grizzly(8)] INFO  com.tinkerpop.rexster.protocol.session.RexProSessions  - RexPro Session destroyed or doesn't otherwise exist: 5b8a669f-615d-4f84-9d1e-2d10624347f0
154529 [Grizzly(1)] INFO  com.tinkerpop.rexster.protocol.session.RexProSessions  - Try to destroy RexPro Session: 00000000-0000-0000-0000-000000000000
154529 [Grizzly(1)] INFO  com.tinkerpop.rexster.protocol.session.RexProSessions  - RexPro Session destroyed or doesn't otherwise exist: 00000000-0000-0000-0000-000000000000

【问题讨论】：

如何开启交易？错误消息似乎很清楚。

感谢您的帮助，我可以通过使用来自here的 rexpro 来实现所需的输出

更新了 rexpro python 的链接：github.com/platinummonkey/rexpro-python

【参考方案1】：

这里是 mogwai 的维护者。

您使用的是什么版本的 mogwai？在 0.7.7 中， setup 方法没有返回值，并且不应传递连接对象。事实上，当您调用 setup 时，它会创建一个连接池（一个同步的 rexpro 连接池，因为没有指定并发选项）。因此，一般来说，在您的应用程序的整个生命周期中只需调用一次 setup ，您就可以在没有任何引用的情况下使用执行查询。

此消息也特别突出：

154525 [Grizzly(7)] WARN  com.tinkerpop.rexster.protocol.server.ScriptServer  - Could not process script [bio4j.E] for language [groovy] on session [[B@6634722f] and request [[B@68f38099]

您的图表是否配置了图表名称“bio4j”？默认的 Titan 图形名称是“graph”，而 mogwai 使用的默认图形对象名称是“g”。如果您的图形名称为“bio4j”，您不会直接引用它，您将使用与事务关联的图形对象名称。您可以将图形名称视为 SQL 数据库中的数据库名称，图形对象是对所述数据库的事务引用。这是在启动 titan 时在 xml 配置文件中配置的。特别是：

<graphs>
    <graph>
        <graph-name>graph</graph-name>
        ....
    </graph>
</graphs>

因此，假设您将其从“graph”更改为“bio4j”，并将设置函数中的默认 graph_obj_name 保留为“g”，那么您的查询应为“g.E”。

【讨论】：

非常感谢，这是我的错，我在rexster.xml文件中更改了图形的名称。再次感谢:)