deploy scala sbt to google app engine - google-app-engine

Question

While importing my scala sbt project to intellij i get the following error
Error while importing SBT project: ...
[info] Loading project definition from /home/dnilesh/Desktop/app-engine/sbt-appengine-demo-master/project
java.lang.RuntimeException: You need to set APPENGINE_SDK_HOME
at scala.sys.package$.error(package.scala:27)
at sbtappengine.Plugin$AppEngine$.buildAppengineSdkPath(AppenginePlugin.scala:103)
at sbtappengine.Plugin$$anonfun$baseAppengineSettings$33.apply(AppenginePlugin.scala:219)
at sbtappengine.Plugin$$anonfun$baseAppengineSettings$33.apply(AppenginePlugin.scala:219)
at sbt.Init$Value$$anonfun$apply$13.apply(Settings.scala:604)
at sbt.EvaluateSettings$$anonfun$sbt$EvaluateSettings$$constant$1.apply(INode.scala:163)
at sbt.EvaluateSettings$$anonfun$sbt$EvaluateSettings$$constant$1.apply(INode.scala:163)
at sbt.EvaluateSettings$MixedNode.evaluate0(INode.scala:175)
at sbt.EvaluateSettings$INode.evaluate(INode.scala:135)
at sbt.EvaluateSettings$$anonfun$sbt$EvaluateSettings$$submitEvaluate$1.apply$mcV$sp(INode.scala:69)
at sbt.EvaluateSettings.sbt$EvaluateSettings$$run0(INode.scala:78)
at sbt.EvaluateSettings$$anon$3.run(INode.scala:74)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
[error] You need to set APPENGINE_SDK_HOME
[error] Use 'last' for the full log.
Invalid response.
See complete log in file:/home/dnilesh/.IdeaIC2017.2/system/log/sbt.last.log Consult IDE log for more details (Help | Show Log)
and while deploying same app to google app engine from terminal i get the same error after that, In terminal i set APPENGINE_SDK_HOME to my google cloud installation directory /usr/lib/google-cloud-sdk/platform/google_appengine/. then i get the following error.
So how can i set APPENGINE_SDK_HOME and to which path so that sbt appengineDeploy command will work.
root#dnilesh-pc:/home/dnilesh/Desktop/app-engine/sbt-appengine-demo-master# sbt appengineDeploy
[info] Loading project definition from /home/dnilesh/Desktop/app-engine/sbt-appengine-demo-master/project
java.lang.RuntimeException: not found appengine api jar.
at scala.sys.package$.error(package.scala:27)
at sbtappengine.Plugin$AppEngine$.buildSdkVersion(AppenginePlugin.scala:114)
at sbtappengine.Plugin$$anonfun$baseAppengineSettings$32.apply(AppenginePlugin.scala:218)
at sbtappengine.Plugin$$anonfun$baseAppengineSettings$32.apply(AppenginePlugin.scala:218)
at scala.Function1$$anonfun$compose$1.apply(Function1.scala:47)
at scala.Function1$$anonfun$compose$1.apply(Function1.scala:47)
at sbt.EvaluateSettings$MixedNode.evaluate0(INode.scala:175)
at sbt.EvaluateSettings$INode.evaluate(INode.scala:135)
at sbt.EvaluateSettings$$anonfun$sbt$EvaluateSettings$$submitEvaluate$1.apply$mcV$sp(INode.scala:69)
at sbt.EvaluateSettings.sbt$EvaluateSettings$$run0(INode.scala:78)
at sbt.EvaluateSettings$$anon$3.run(INode.scala:74)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
[error] not found appengine api jar.
[error] Use 'last' for the full log.

Answer 1

Steps I did to sort out this issue:
Download the App Engine SDK for Java:
Google App Engine
Direct Download Link
Extract it in your computer regardless your GCloud installed path.
set APPENGINE_SDK_HOME :
export APPENGINE_SDK_HOME= /PATH/TO/SDK/appengine-java-sdk-1.9.54
Download Sample Scala sbt application.
Github Sample Scala App
run sbt appengineDeploy command to run app. change project id to your project id on google cloud. Steps before running app
Notes:
You cannot install third party databases like mongodb on gae.
gae does not support akka framework.
gae does not support multithreading.