https://github.com/estatico/scala-newtype https://github.com/gnieh/diffson
// "io.estatico" %% "newtype" % "0.4.4", // "eu.timepit" %% "refined" % "0.9.20"
Conversions Between Java and Scala Collections <= 2.12 Conversions Between Java and Scala Collections == 2.13
// 2.12
import collection.JavaConverters._
// 2.13
import scala.jdk.CollectionConverters._
ArrayBuffer(1, 2, 3).asJava.asScala
import cats.data.Writer
import scala.annotation.tailrec
def countAndLog(n: Int): Writer[Vector[String], Int] = {
@tailrec
def f(in: Writer[List[String], Int]): Writer[List[String], Int] =
if (in.value <= 0) in.mapWritten("starting!" :: _)
else f(in.mapBoth((l, v) => (s"$v" :: l, v - 1)))
f(Writer(Nil, n)).mapWritten(_.to(Vector))
}
println(countAndLog(10).run)
implicit val ec = ExecutionContext.fromExecutor(
Executors.newFixedThreadPool(4))recover -> T recoverWith -> F[T]
statically-checked at compile time!
Type Enrichment
implicit class Foo(val t: T) extends AnyVal {
def anEnrichingMethod(): U = ???
}implicit def f(t: T): U = ???implicit class FooOps[T](value: T) { def f(implicit actioner: Bar[T]): Baz = actioner.f(value) }
disambiguates what this means when functions are defined in a class. You can always refer to self (or whatever you call it, it's arbitrary) when talking about the enclosing class
trait Foo {
self =>
}
In many cases, this is better than using a raw case class. Extractor Objects docs
scala parallel test execution
testOptions in Test += Tests.Argument("-P")
ParallelTestExecution
list map { case Some(x) => x case None => default }
Scala Array Extractor
a.foreach(e => { e match { case a: Array[Int] if a.last == 5 => case _ => } }) You can do something a little better for matching on the first elements: a.foreach(e => { e match { case Array(1, *) => case _ => } }) Unfortunately the @* thing has to be the last item in the list of array arguments. But you can make the matching before that as complex as you want. scala> val Array(1, x @_*) = Array(1,2,3,4,5) x: Seq[Int] = Vector(2, 3, 4, 5)
scala> val Array(1, b, 3, x @_*) = Array(1,2,3,4,5) b: Int = 2 x: Seq[Int] = Vector(4, 5)
import scala.sys.process._
addCommandAlias("it", "runIntegrationTestsInDocker")
lazy val runIntegrationTestsInDocker = taskKey[Unit]("Runs Integration Tests within Docker container")
runIntegrationTestsInDocker := {
s"""
|docker run -i
| --mount type=bind,src=${sys.props("user.dir")},dst=/w
| --mount type=bind,src=${sys.env("HOME")}/.ivy2,dst=/root/.ivy2
| --mount type=bind,src=${sys.env("HOME")}/Library/Caches/Coursier,dst=/root/.cache/coursier
| -w /w
| -e AWS_SECRET_ACCESS_KEY=${sys.env("AWS_SECRET_ACCESS_KEY")}
| -e AWS_ACCESS_KEY_ID=${sys.env("AWS_ACCESS_KEY_ID")}
| s22s/rasterframes-circleci
| sbt
| it:test
""".stripMargin.split("\n").mkString.!
}
Metals
metals.showInferredType
docker run --rm -p 22909:22909 s22s/eod-catalog-svc:latest
dependencyCheckSkipProvidedScope := true,
dependencyCheckFailBuildOnCVSS := 0,
dependencyCheckSuppressionFiles := Seq(new File("dependency-check-suppressions.xml"))
class FooSpec extends AnyFlatSpec with Matchers with ScalaFutures with Inspectors with OptionValues
it should "do something" in {
it should "do something" ignore {
// Current test -- taggedAs Current package foo
import org.scalatest.Tag
object Current extends Tag("foo.Current")
type Vare[A] = ValidatedNec[ItemValidation, A] // Vare == Validation Result
def time[R](tag: String)(block: => R)(implicit logger: Logger): R = {
val start = System.currentTimeMillis()
val result = block
val end = System.currentTimeMillis()
logger.info(f"Elapsed time of
logback.xml
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
<!-- encoders are assigned the type
ch.qos.logback.classic.encoder.PatternLayoutEncoder by default -->
<encoder>
<pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
</encoder>
</appender>
<root level="debug">
<appender-ref ref="STDOUT"/>
</root>
<logger name="com.sksamuel.elastic4s" level="error" additivity="false">
<appender-ref ref="consoleAppender"/>
</logger>
<logger name="software.amazon.awssdk.auth.credentials" level="OFF"/>
/** Anything that structurally has a close method. */ type CloseLike = { def close(): Unit }
/** Applies the given thunk to the closable resource. */ def using[T <: CloseLike, R](t: T)(thunk: T => R): R = { try { thunk(t) } finally { t.close() } }
val NoStore: Cache-Control = Cache-Control(no-cache, no-store, must-revalidate)
val NoCache: Cache-Control = Cache-Control(no-cache)
val MaxAgeTenMin: Cache-Control = Cache-Control(max-age(600), must-revalidate)
import akka.http.scaladsl.model.StatusCode
/**
- We want to be able to fail a future with
ErrorResult - but since it doesn't extend
Throwablewe need to wrap it into one. */ case class Error( code: StatusCode, title: Option[String] = None, detail: Option[String] = None ) extends Throwable(title.orNull)
private[errors] class ErrorFactory(code: StatusCode) {
def apply(): Error =
Error(code)
def apply(title: String): Error =
Error(code, Some(title))
def apply(title: String, detail: String): Error =
Error(code, Some(title), Some(detail))
}
object NotFound extends ErrorFactory(StatusCodes.NotFound)
object Forbidden extends ErrorFactory(StatusCodes.Forbidden)
object BadRequest extends ErrorFactory(StatusCodes.BadRequest)
object Unexpected extends ErrorFactory(StatusCodes.InternalServerError)
object PreconditionFailed extends ErrorFactory(StatusCodes.PreconditionFailed)
Acode
gdal_translate
gdal_translate x.tif x_cog.tif -of COG -co COMPRESS=DEFLATE -co NUM_THREADS=ALL_CPUS --config GDAL_CACHEMAX 1024
Bash params
#!/usr/bin/env bash set -Eeuo pipefail set -x
suffix=${1-TIF} srcName=$2 prefix=${2%.$suffix} originalName=${prefix}-original.tif cogName=${prefix}-cog.tif
project/plugins.sbt
addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.14.10") addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.4.2") addSbtPlugin("net.virtual-void" % "sbt-dependency-graph" % "0.10.0-RC1") addSbtPlugin("net.vonbuchholtz" % "sbt-dependency-check" % "3.0.0") addSbtPlugin("de.heikoseeberger" % "sbt-header" % "5.6.0") addSbtPlugin("com.typesafe.sbt" % "sbt-license-report" % "1.2.0") addSbtPlugin("com.github.cb372" % "sbt-explicit-dependencies" % "0.2.15") addSbtPlugin("io.spray" % "sbt-revolver" % "0.9.1") addSbtPlugin("com.typesafe.sbt" % "sbt-git" % "1.0.0") addSbtPlugin("com.timushev.sbt" % "sbt-updates" % "0.5.1") addSbtPlugin("com.github.gseitz" % "sbt-release" % "1.0.13")
addSbtPlugin("com.typesafe.sbt" % "sbt-native-packager" % "1.5.2") addSbtPlugin("com.mintbeans" % "sbt-ecr" % "0.15.0")
addSbtPlugin("com.lightbend.sbt" % "sbt-javaagent" % "0.1.5") addSbtPlugin("org.openapitools" % "sbt-openapi-generator" % "5.0.0") addSbtPlugin("com.eed3si9n" % "sbt-buildinfo" % "0.10.0")
implicit ordering
Implicit scope
- normal scope = local scope
- imported scope
- companions of all types involved in the method signature, incl. A and supertypes
scala> Option.empty[Int] == Option.empty[String] val res2: Boolean = true
Prelude> let x = Nothing :: Maybe Int Prelude> let y = Nothing :: Maybe String Prelude> x Nothing Prelude> y Nothing Prelude> x == y
:8:6: error: • Couldn't match type ‘[Char]’ with ‘Int’ Expected type: Maybe Int Actual type: Maybe String • In the second argument of ‘(==)’, namely ‘y’ In the expression: x == y In an equation for ‘it’: it = x == y
FlatSpec or FlatSpecLike
Matchers
ArgumentMatchersSugar IdiomaticMockito withClue for exceptions
it should "" in { } ignore should "" in {} "X" should "Y" in {} "X" should "Y" ignore {}
taggedAs -n io.astraea.Current
PropSpec for properties Fixtures
Eventually http://doc.scalatest.org/1.8/org/scalatest/concurrent/Eventually.html
How to handle inconsistent results?
testOptions in Test += Tests.Argument(TestFrameworks.ScalaTest, "-P5")
ParallelTestExecution
http://doc.scalatest.org/1.8/org/scalatest/concurrent/Eventually.html
Older
should == must
list.size shouldBe 3
result should equal (3) // can customize equality result should === (3) // can customize equality and enforce type constraints result should be (3) // cannot customize equality, so fastest to compile result shouldEqual 3 // can customize equality, no parentheses required result shouldBe 3 // cannot customize equality, so fastest to compile, no parentheses required
result should have size 10
should be theSameInstanceAs
val string = """I fell into a burning ring of fire. I went down, down, down and the flames went higher""" string should startWith("I fell") string should endWith("higher") string should not endWith "My favorite friend, the end" string should include("down, down, down") string should not include ("Great balls of fire")
string should startWith regex ("I.fel+") string should endWith regex ("h.{4}r") string should not endWith regex("\d{5}") string should include regex ("flames?")
string should fullyMatch regex ("""I(.|\n|\S)*higher""")
"abbccxxx" should startWith regex ("a(b*)(c*)" withGroups ("bb", "cc"))
xs should contain theSameElementsAs Seq()
one should be < 7 one should be > 0 one should be <= 7 one should be >= 0
x shouldBe 'booleanF
num shouldBe odd num should not be even
ref1 should be theSameInstanceAs ref2
sevenDotOh shouldBe 6.9 +- 0.2
traversable shouldBe empty javaMap should not be empty
traversable should contain ("five")
should contain oneOf should contain noneOf should contain atLeastOneOf (2, 3, 4) should contain atMostOneOf (5, 6, 7) contain allOf (2, 3, 5) contain only
(Vector(" A", "B ") should contain atLeastOneOf ("a ", "b", "c")) (after being lowerCased and trimmed)
should contain inOrderOnly
should contain inOrder
should contain theSameElementsInOrderAs -- same iteration order
FlatSpec "An empty Set" should "have size 0" in { it should "produce NoSuchElementException when head is invoked" in {
http://www.scalatest.org/user_guide/using_matchers https://scalamock.org/ https://www.safaribooksonline.com/library/view/testing-in-scala/9781449360313/ch05.html