Gremlin Python加载CSV时出现org.apache.commons.csv.CSVFormat类解析错误

使用Gremlin Python加载CSV文件时出现以下错误：

{'error': GremlinServerError('597: startup failed:\r\nScript5.groovy: 2: unable to resolve class org.apache.commons.csv.CSVFormat\n @ line 2, column 1.\n import org.apache.commons.csv.CSVFormat\n ^\n\n1 error\n')}

已在Gremlin控制台成功加载该CSV文件（包含顶点和边），Python端代码如下：

from gremlin_python.driver.driver_remote_connection import DriverRemoteConnection
from gremlin_python.structure.graph import Graph
from gremlin_python import statics
from gremlin_python.process.graph_traversal import __
from gremlin_python.process.strategies import *
from gremlin_python.process.traversal import *
import sys

from gremlin_python.driver.aiohttp.transport import AiohttpTransport

# Path to our graph (this assumes a locally running Gremlin Server)
# Note how the path is a Web Socket (ws) connection.
endpoint = 'ws://localhost:8182/gremlin'

# Obtain a graph traversal source using a remote connection
graph=Graph()
connection = DriverRemoteConnection(endpoint,'g',
                 transport_factory=lambda:AiohttpTransport(call_from_event_loop=True))
g = graph.traversal().withRemote(connection)

%%graph_notebook_config
{
  "host": "localhost",
  "port": 8182,
  "ssl": false,
  "gremlin": {
    "traversal_source": "g"
  }
}

%%gremlin
g = TinkerGraph.open().traversal()
import org.apache.commons.csv.CSVFormat
fileReader = new FileReader('C:/airports.csv')
records = CSVFormat.RFC4180.withFirstRecordAsHeader().parse(fileReader);[]
records.each{
    c=it.get('code');
    d=it.get('desc');
    println(it)
    g.V().has('code', c).fold().coalesce(
        unfold(),
        addV('airport').property('code',c).property('desc',d)
    ).iterate()
}
g.V().count()

在Gremlin控制台中通过以下命令配置服务器：

:remote connect tinkerpop.server conf/remote.yaml

CSV文件包含两列，示例数据：code:TXF，desc:"9 de Maio - Teixeira de Freitas Airport"

1. 补充Gremlin Server依赖包 #

错误提示找不到org.apache.commons.csv.CSVFormat类，说明Gremlin Server的classpath中缺少Apache Commons CSV依赖：

• 下载与Gremlin Server版本兼容的Apache Commons CSV jar包
• 将jar包复制到Gremlin Server安装目录下的lib文件夹
• 重启Gremlin Server

2. 修正Gremlin脚本逻辑 #

Python代码中%%gremlin块的脚本存在两处问题：

• 重新创建了TinkerGraph实例，未使用已配置的遍历源g
• 脚本末尾多余的;[]会导致执行异常

修改后的脚本：

import org.apache.commons.csv.CSVFormat
fileReader = new FileReader('C:/airports.csv')
records = CSVFormat.RFC4180.withFirstRecordAsHeader().parse(fileReader)
records.each{
    c=it.get('code');
    d=it.get('desc');
    g.V().has('code', c).fold().coalesce(
        unfold(),
        addV('airport').property('code',c).property('desc',d)
    ).iterate()
}
g.V().count()

3. 替代方案：Python本地读取CSV后批量插入 #

若不想修改Gremlin Server依赖，可在Python端直接读取CSV，再通过Gremlin Python发送遍历请求插入数据：

import csv

# 读取本地CSV文件
with open('C:/airports.csv', 'r', encoding='utf-8') as f:
    reader = csv.DictReader(f)
    for row in reader:
        code = row['code']
        desc = row['desc']
        # 执行插入逻辑
        g.V().has('code', code).fold().coalesce(
            __.unfold(),
            __.addV('airport').property('code', code).property('desc', desc)
        ).iterate()

# 统计顶点数量
print(g.V().count().next())

内容的提问来源于stack exchange，提问作者Aureon