add spark version validation (#69)

* add spark version validation

* Add spark version info in Compatibility Matrix

---------

Co-authored-by: Wey Gu <weyl.gu@gmail.com>

Author: Nicole00

README.md

@@ -111,19 +111,23 @@ If you want to write the algorithm execution result into NebulaGraph(`sink: nebu
 |            bfs           |            dfs          |    string   |
 |         jaccard          |          jaccard        |    string   |
 |        node2vec          |          node2vec       |    string   |
-    
+
+
+<!--- We cannot change name of this chapter, or the version checker code will be broken --->
+
 ## Version Compatibility Matrix
 
-| Nebula Algorithm Version | Nebula Version |
-|:------------------------:|:--------------:|
-|       2.0.0              |  2.0.0, 2.0.1  |
-|       2.1.0              |  2.0.0, 2.0.1  |
-|       2.5.0              |  2.5.0, 2.5.1  |
-|       2.6.0              |  2.6.0, 2.6.1  |
-|       2.6.1              |  2.6.0, 2.6.1  |
-|       2.6.2              |  2.6.0, 2.6.1  |
-|       3.0.0              |  3.0.x, 3.1.x, 3.2.x, 3.3.x |
-|       3.0-SNAPSHOT       |     nightly    |
+| NebulaGraph Algorithm Version |    NebulaGraph Version     | Spark Version |
+| :---------------------------: | :------------------------: | ------------- |
+|             2.0.0             |        2.0.0, 2.0.1        | 2.4           |
+|             2.1.0             |        2.0.0, 2.0.1        | 2.4           |
+|             2.5.0             |        2.5.0, 2.5.1        | 2.4           |
+|             2.6.0             |        2.6.0, 2.6.1        | 2.4           |
+|             2.6.1             |        2.6.0, 2.6.1        | 2.4           |
+|             2.6.2             |        2.6.0, 2.6.1        | 2.4           |
+|         3.0.0, 3.1.x          | 3.0.x, 3.1.x, 3.2.x, 3.3.x | 2.4           |
+|         3.0-SNAPSHOT          |          nightly           | 2.4           |
+
 
 ## Contribute
 

nebula-algorithm/src/main/scala/com/vesoft/nebula/algorithm/config/SparkConfig.scala

@@ -25,6 +25,17 @@ object SparkConfig {
       session.config(key, sparkConfigs(key))
     }
     partitionNum = sparkConfigs.getOrElse("spark.app.partitionNum", "0")
-    SparkConfig(session.getOrCreate(), partitionNum)
+    val spark = session.getOrCreate()
+    validate(spark.version, "2.4.*")
+    SparkConfig(spark, partitionNum)
+  }
+
+  def validate(sparkVersion: String, supportedVersions: String*): Unit = {
+    if (sparkVersion != "UNKNOWN" && !supportedVersions.exists(sparkVersion.matches)) {
+      throw new RuntimeException(
+        s"""Your current spark version ${sparkVersion} is not supported by the current NebulaGraph Algorithm.
+           | please visit https://github.com/vesoft-inc/nebula-algorithm#version-compatibility-matrix to know which version you need.
+           | """.stripMargin)
+    }
   }
 }