Mezcal is a lightweight, fast Cassandra database access layer for Scala keeping complete control over the CQL.
SinglePreparedStatement.scala created using the custom string interpolation method cql.
Method selectOne in SelectOneAsync.scala make a function with closure.
val getUser: (Tuple2[Int, String]) => Future[User] =
cql"SELECT * FROM profiles WHERE id = ? AND name = ?"
.selectOne[(Int, String), User](tracing = ExecutionInfo.ENABLE)
getUser(30, "Tervo").foreach(println)Write the trace query information to the log output if tracing is enabled (as in the query above).
21/05/09 21:26:24 [INFO] [QueryTracePrinter] Tracing session: 0f905c80-b0f4-11eb-8753-f9c5ada0271a
Execute: SELECT * FROM users WHERE id = ? AND name = ?;
Bound: id = 30;
Bound: name = 'Tervo';
Per-statement: consistency_level = LOCAL_QUORUM;
Per-statement: serial_consistency_level = SERIAL;
Per-statement: page_size = 1;
------------------------------------------------------------------------+---------------+----------------+-------------
activity | timestamp | source | elapsed time
------------------------------------------------------------------------+---------------+----------------+-------------
Execute CQL3 prepared query | 1620558695579 | /192.168.7.142 | 0
Executing single-partition query on users | 1620558695579 | /192.168.7.142 | 135
Acquiring sstable references | 1620558695579 | /192.168.7.142 | 251
Merging memtable contents | 1620558695579 | /192.168.7.142 | 283
Read 1 live rows and 0 tombstone cells | 1620558695579 | /192.168.7.142 | 350
Request complete | - | - | 406
------------------------------------------------------------------------+---------------+----------------+-------------
See QueryAsyncSpec.scala for documentation.
- Java 8, 11
- Scala 2.13
- Datastax Java Driver 3.11.0
- Logging backend compatible with SLF4J
A compatible logging backend is Logback, add it to your sbt build definition:
val overrides = {
val `SLF4J` = "1.7.32"
List(
"org.slf4j" % "slf4j-api" % `SLF4J`
)
}
val commons = {
val `LOGBACK` = "1.2.4"
val `SCALA-LOGGING` = "3.9.4"
List(
"ch.qos.logback" % "logback-classic" % `LOGBACK`,
"com.typesafe.scala-logging" %% "scala-logging" % `SCALA-LOGGING` exclude ("org.slf4j", "slf4j-api")
)
}SBT users may add this to their Dependencies.scala:
val commons = {
val `MEZCAL` = "0.5"
val `NETTY` = "4.1.73.Final"
val driver = List(
"com.ensime" %% "mezcal" % `MEZCAL`
)
val epoll =
if (sys.props("os.name") == "Linux")
List("io.netty" % "netty-transport-native-epoll" % `NETTY` classifier "linux-x86_64")
else
Nil
driver ::: epoll
}Copyright (C) 2022 Vadim Kornev.
Distributed under the MIT License.
