add check for already installed packages before installing them

src/main/kotlin/org/domaindrivenarchitecture/provs/framework/ubuntu/install/base/Install.kt

@@ -10,20 +10,29 @@ private var aptInit = false
  * Installs package(s) by using package manager "apt".
  *
  * @param packages the packages to be installed, packages must be separated by space if there are more than one
+ * @param ignoreAlreadyInstalled if true, then for an already installed package no action will be taken,
+ * if "ignoreAlreadyInstalled" is false, then installation is always attempted, which normally results in an upgrade if package wa already installed
  */
-fun Prov.aptInstall(packages: String): ProvResult = task {
+fun Prov.aptInstall(packages: String, ignoreAlreadyInstalled: Boolean = true): ProvResult = task {
+    val packageList = packages.split(" ")
+    val allInstalled: Boolean = packageList.map { isPackageInstalled(it) }.fold(true, { a, b -> a && b })
+    if (!allInstalled) {
+        if (!isPackageInstalled(packages)) {
             if (!aptInit) {
                 cmd("sudo apt-get update")
                 cmd("sudo apt-get install -qy apt-utils")
                 aptInit = true
             }
+        }
 
-    val packageList = packages.split(" ")
         for (packg in packageList) {
             // see https://superuser.com/questions/164553/automatically-answer-yes-when-using-apt-get-install
             cmd("sudo DEBIAN_FRONTEND=noninteractive apt-get install -qy $packg")
         }
         ProvResult(true) // dummy
+    } else {
+        ProvResult(true, out = "All packages are already installed. [$packages]")
+    }
 }
 
 

src/test/kotlin/org/domaindrivenarchitecture/provs/framework/ubuntu/install/base/InstallKtTest.kt

@@ -2,6 +2,7 @@ package org.domaindrivenarchitecture.provs.framework.ubuntu.install.base
 
 import org.domaindrivenarchitecture.provs.test.defaultTestContainer
 import org.domaindrivenarchitecture.provs.test.tags.ContainerTest
+import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Assertions.assertTrue
 import org.junit.jupiter.api.Disabled
 import org.junit.jupiter.api.Test
@@ -22,6 +23,20 @@ internal class InstallKtTest {
         assertTrue(res.success)
     }
 
+    @ContainerTest
+    @Test
+    fun aptInstall_ignores_packages_already_installed() {
+        // given
+        val a = defaultTestContainer()
+
+        // when
+        val res = a.aptInstall("sed grep")
+
+        // then
+        assertTrue(res.success)
+        assertEquals("All packages are already installed. [sed grep]", res.out)
+    }
+
     @ContainerTest
     @Test
     @Disabled  // run manually if needed;