feat(analytics): add Structured Streaming, MLlib clustering, GraphX jobs

Three new Spark jobs demonstrating complementary Spark pillars:

LiveDashboardJob (Structured Streaming):
- Simulates NowChess game-over event stream via rate source
- Watermarking (45 s late-data tolerance)
- Tumbling 1-min windows → append-mode Parquet output
- Sliding 5-min/1-min windows → update-mode console output
- Checkpointing for exactly-once fault tolerance
- Production wiring comments show Kafka / spark-redis swap-in

PlayerClusteringJob (MLlib):
- Derives 4 player features from game_records via JDBC
- VectorAssembler + StandardScaler + KMeans inside a Pipeline
- ClusteringEvaluator (silhouette score) to measure quality
- Per-cluster archetype averages show what each tier represents

PlayerGraphJob (GraphX):
- Builds directed player graph (vertices=players, edges=games)
- PageRank — identifies most influential/active players
- ConnectedComponents — finds isolated player communities
- Bridges GraphX RDD results back to DataFrames via explicit schema
  (avoids spark.implicits._ which breaks Scala 3 → Spark 2.13 interop)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
Janis Eccarius
2026-06-15 22:15:24 +02:00
parent 259b3bbb24
commit e1d80b9331
4 changed files with 449 additions and 0 deletions
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package de.nowchess.analytics
import org.apache.spark.ml.Pipeline
import org.apache.spark.ml.clustering.KMeans
import org.apache.spark.ml.evaluation.ClusteringEvaluator
import org.apache.spark.ml.feature.StandardScaler
import org.apache.spark.ml.feature.VectorAssembler
import org.apache.spark.sql.SparkSession
import org.apache.spark.sql.functions as F
/** Clusters NowChess players into skill tiers using K-Means via MLlib.
*
* Spark / MLlib concepts shown:
* - Feature engineering from raw relational data (JDBC → DataFrame)
* - VectorAssembler — combine scalar columns into a dense feature vector
* - StandardScaler — zero-mean / unit-variance normalisation so that total_games (can be 1000+) does not dominate
* win_rate (01)
* - KMeans clustering — unsupervised partitioning into k skill tiers
* - Pipeline — compose transformers + estimator into a single reusable object
* - ClusteringEvaluator — silhouette score to assess cluster quality
*
* Features per player (all derived from game_records): total_games — how active the player is win_rate — overall
* strength avg_move_count — game-length preference (tactical vs positional) games_as_white_ratio — colour bias
*
* Output: Parquet: player_id + cluster (0..k-1) + feature values CSV: per-cluster archetype averages (interpret what
* each tier means)
*/
object PlayerClusteringJob:
def main(args: Array[String]): Unit =
val jdbcUrl = sys.env.getOrElse("NOWCHESS_JDBC_URL", "jdbc:postgresql://localhost:5432/nowchess")
val dbUser = sys.env.getOrElse("NOWCHESS_DB_USER", "nowchess")
val dbPass = sys.env.getOrElse("NOWCHESS_DB_PASS", "nowchess")
val outputDir = if args.length > 0 then args(0) else "/tmp/nowchess-player-clusters"
val k = if args.length > 1 then args(1).toInt else 4
val spark = SparkSession
.builder()
.appName("NowChess Player Clustering")
.getOrCreate()
run(spark, jdbcUrl, dbUser, dbPass, outputDir, k)
spark.stop()
def run(
spark: SparkSession,
jdbcUrl: String,
dbUser: String,
dbPass: String,
outputDir: String,
k: Int,
): Unit =
val games = spark.read
.format("jdbc")
.option("url", jdbcUrl)
.option("dbtable", "game_records")
.option("user", dbUser)
.option("password", dbPass)
.option("driver", "org.postgresql.Driver")
.option("fetchsize", "10000")
.load()
.select("white_id", "black_id", "result", "move_count")
.filter(F.col("result").isNotNull)
val playerStats = buildPlayerStats(games)
.filter(F.col("total_games") >= 5)
val featureCols = Array("total_games", "win_rate", "avg_move_count", "games_as_white_ratio")
val assembler = new VectorAssembler()
.setInputCols(featureCols)
.setOutputCol("raw_features")
.setHandleInvalid("skip")
val scaler = new StandardScaler()
.setInputCol("raw_features")
.setOutputCol("features")
.setWithStd(true)
.setWithMean(true)
val kmeans = new KMeans()
.setK(k)
.setSeed(42L)
.setFeaturesCol("features")
.setPredictionCol("cluster")
val pipeline = new Pipeline().setStages(Array(assembler, scaler, kmeans))
val model = pipeline.fit(playerStats)
val predictions = model.transform(playerStats)
val silhouette = new ClusteringEvaluator()
.setFeaturesCol("features")
.setPredictionCol("cluster")
.evaluate(predictions)
println(s"[Clustering] k=$k silhouette=$silhouette")
// Average feature values per cluster reveal what each tier represents.
// Example interpretation for k=4:
// Cluster 0: high total_games + high win_rate → experienced strong players
// Cluster 1: low total_games + low win_rate → beginners / casual
// Cluster 2: high total_games + mid win_rate → active intermediate
// Cluster 3: low total_games + high win_rate → strong but infrequent
val archetypes = predictions
.groupBy("cluster")
.agg(
F.count("*").as("player_count"),
F.round(F.avg("total_games"), 1).as("avg_total_games"),
F.round(F.avg("win_rate"), 3).as("avg_win_rate"),
F.round(F.avg("avg_move_count"), 1).as("avg_move_count"),
F.round(F.avg("games_as_white_ratio"), 3).as("avg_white_ratio"),
)
.orderBy("cluster")
archetypes.show(20, false)
predictions
.select("player_id", "total_games", "win_rate", "avg_move_count", "cluster")
.write
.mode("overwrite")
.parquet(s"$outputDir/player_clusters")
archetypes.write
.mode("overwrite")
.option("header", "true")
.csv(s"$outputDir/cluster_archetypes")
private def buildPlayerStats(games: org.apache.spark.sql.DataFrame): org.apache.spark.sql.DataFrame =
val asWhite = games.select(
F.col("white_id").as("player_id"),
F.col("result"),
F.col("move_count"),
F.lit(1).as("is_white"),
)
val asBlack = games.select(
F.col("black_id").as("player_id"),
F.col("result"),
F.col("move_count"),
F.lit(0).as("is_white"),
)
val won = (F.col("is_white") === 1 && F.col("result") === "white")
.or(F.col("is_white") === 0 && F.col("result") === "black")
asWhite
.union(asBlack)
.groupBy("player_id")
.agg(
F.count("*").as("total_games"),
F.round(F.sum(F.when(won, 1.0).otherwise(0.0)) / F.count("*"), 3).as("win_rate"),
F.round(F.avg(F.col("move_count")), 1).as("avg_move_count"),
F.round(F.avg(F.col("is_white").cast("double")), 3).as("games_as_white_ratio"),
)