chore: add prerequisite check before build (#8929)

This PR is difficult to test, since it's checking for globally installed dependencies like Java, Dotnet, etc. I'm concerned mostly about the effects on our build process, since there may be regex patterns for valid installed versions that I missed.

Hopefully it will have a positive influence on adoption for new contributors by telling them exactly what they are missing before getting deep into a build and seeing confusing error messages.

Closes Issue #8847.

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

CONTRIBUTING.md

@@ -77,19 +77,19 @@ you need to have the following SDKs and tools locally:
 - [Node.js >= 10.13.0](https://nodejs.org/download/release/latest-v10.x/)
   - We recommend using a version in [Active LTS](https://nodejs.org/en/about/releases/)
   - ⚠️ versions `13.0.0` to `13.6.0` are not supported due to compatibility issues with our dependencies.
-- [Yarn >= 1.19.1](https://yarnpkg.com/lang/en/docs/install)
-- [Java OpenJDK 8](https://docs.aws.amazon.com/corretto/latest/corretto-8-ug/downloads-list.html)
-- [Apache Maven](http://maven.apache.org/install.html)
-- [.NET Core SDK 3.1](https://www.microsoft.com/net/download)
-- [Python 3.6.5](https://www.python.org/downloads/release/python-365/)
-- [Ruby 2.5.1](https://www.ruby-lang.org/en/news/2018/03/28/ruby-2-5-1-released/)
+- [Yarn >= 1.19.1, < 1.3](https://yarnpkg.com/lang/en/docs/install)
+- [Java >= OpenJDK 8, 11, 14](https://docs.aws.amazon.com/corretto/latest/corretto-8-ug/downloads-list.html)
+- [Apache Maven >= 3.6.0, < 4.0](http://maven.apache.org/install.html)
+- [.NET Core SDK 3.1.x](https://www.microsoft.com/net/download)
+- [Python >= 3.6.5, < 4.0](https://www.python.org/downloads/release/python-365/)
+- [Ruby >= 2.5.1, < 3.0](https://www.ruby-lang.org/en/news/2018/03/28/ruby-2-5-1-released/)
+- [Docker 19.03](https://docs.docker.com/get-docker/)
 
 The basic commands to get the repository cloned and built locally follow:
 
 ```console
 $ git clone https://github.com/aws/aws-cdk.git
 $ cd aws-cdk
-$ yarn install
 $ yarn build
 ```
 

build.sh

@@ -38,8 +38,12 @@ fail() {
   exit 1
 }
 
+# Check for secrets that should not be committed
 /bin/bash ./git-secrets-scan.sh
 
+# Verify dependencies before starting the build
+/bin/bash ./scripts/check-prerequisites.sh
+
 # Prepare for build with references
 /bin/bash scripts/generate-aggregate-tsconfig.sh > tsconfig.json
 

scripts/check-prerequisites.sh

@@ -0,0 +1,174 @@
+#!/bin/bash
+set -euo pipefail
+
+# Testing with this to simulate different installed apps:
+# docker run -it -v ~/Source/aws-cdk:/var/cdk ubuntu bash
+
+# Note: Don't use \d in regex, it doesn't work on Macs without GNU tools installed
+# Use [0-9] instead
+
+app=""
+app_min=""
+app_v=""
+
+die() { echo "$*" 1>&2 ; exit 1; }
+wrong_version() { echo "Found $app version $app_v. Install $app >= $app_min" 1>&2; exit 1; }
+
+check_which() {
+    local app=$1
+    local min=$2
+
+    echo -e "Checking if $app is installed... \c"
+
+    w=$(which ${app}) || w=""
+
+    if [ -z $w ] || [ $w == "$app not found" ]
+    then
+        die "Missing dependency: $app. Install $app >= $min"
+    else
+        echo "Ok"
+    fi
+}
+
+# [Node.js >= 10.13.0]
+#   ⚠️ versions `13.0.0` to `13.6.0` are not supported due to compatibility issues with our dependencies.
+app="node"
+app_min="v10.13.0"
+check_which $app $app_min
+app_v=$(node --version)
+
+# Check for version 10.*.* - 29.*.*
+echo -e "Checking node version... \c"
+if [ $(echo $app_v | grep -c -E "v[12][0-9]\.[0-9]+\.[0-9]+") -eq 1 ]
+then    
+    # Check for version 13.0 to 13.6
+    if [ $(echo $app_v | grep -c -E "v13\.[0-6]\.[0-9]+") -eq 1 ]
+    then
+        die "node versions 13.0.0 to 13.6.0 are not supported due to compatibility issues with our dependencies."
+    else
+        # Check for version < 10.13
+        if [ $(echo $app_v | grep -c -E "v10\.([0-9]|1[0-2])\.[0-9]+") -eq 1 ]
+        then   
+            wrong_version
+        else
+            echo "Ok"
+        fi
+    fi
+else    
+    echo "Not 12"
+    wrong_version
+fi
+
+# [Yarn >= 1.19.1, < 1.30]
+app="yarn"
+app_min="1.19.1"
+check_which $app $app_min
+app_v=$(${app} --version)
+echo -e "Checking yarn version... \c"
+if [ $(echo $app_v | grep -c -E "1\.(19|2[0-9])\.[0-9]+") -eq 1 ]
+then   
+    echo "Ok"
+else
+    wrong_version
+fi
+
+# [Java OpenJDK 8, 11, 14]
+
+# Follow "More Info" on a new Mac when trying javac, install latest Oracle:
+# javac 14.0.1
+
+# apt install default-jdk on Ubuntu
+# javac 11.0.7
+
+# Install Coretto 8 from Amazon web site
+# javac --version fails
+# javac -version
+# javac 1.8.0_252
+# Old javac versions output version to stderr... why
+
+app="javac"
+app_min="1.8.0"
+check_which $app $app_min
+app_v=$(${app} -version 2>&1)
+echo -e "Checking javac version... \c"
+# 1.8
+if [ $(echo $app_v | grep -c -E "1\.8\.[0-9].*") -eq 1 ]
+then   
+    echo "Ok"
+else
+    # 11 or 14
+    if [ $(echo $app_v | grep -c -E "1[14]\.[0-9]\.[0-9].*") -eq 1 ]
+    then    
+        echo "Ok"
+    else
+        wrong_version
+    fi
+fi
+
+# [Apache Maven >= 3.6.0, < 4.0]
+app="mvn"
+app_min="3.6.0"
+check_which $app $app_min
+app_v=$(${app} --version)
+echo -e "Checking mvn version... \c"
+if [ $(echo $app_v | grep -c -E "3\.[6789]\.[0-9].*") -eq 1 ]
+then   
+    echo "Ok"
+else
+    wrong_version
+fi
+
+# [.NET Core SDK 3.1.*]
+app="dotnet"
+app_min="3.1.0"
+check_which $app $app_min
+app_v=$(${app} --version)
+echo -e "Checking $app version... \c"
+if [ $(echo $app_v | grep -c -E "3\.1\.[0-9].*") -eq 1 ]
+then   
+    echo "Ok"
+else
+    wrong_version
+fi
+
+# [Python >= 3.6.5, < 4.0]
+app="python3"
+app_min="3.6.5"
+check_which $app $app_min
+app_v=$(${app} --version)
+echo -e "Checking $app version... \c"
+if [ $(echo $app_v | grep -c -E "3\.[6789]\.[0-9].*") -eq 1 ]
+then   
+    echo "Ok"
+else
+    wrong_version
+fi
+
+# [Ruby >= 2.5.1, < 3.0]
+app="ruby"
+app_min="2.5.1"
+check_which $app $app_min
+app_v=$(${app} --version)
+echo -e "Checking $app version... \c"
+if [ $(echo $app_v | grep -c -E "2\.[56789]\.[0-9].*") -eq 1 ]
+then   
+    echo "Ok"
+else
+    wrong_version
+fi
+
+# [Docker >= 19.03]
+app="docker"
+app_min="19.03.0"
+check_which $app $app_min
+
+# Make sure docker is running
+echo -e "Checking if docker is running... \c"
+docker_running=$(docker ps)
+if [ $? -eq 0 ]
+then    
+    echo "Ok"
+else
+    die "Docker is not running"
+fi
+