add utility to interrogate os-release file

src/main/java/emissary/util/os/OSReleaseUtil.java

@@ -0,0 +1,74 @@
+package emissary.util.os;
+
+import org.apache.commons.lang3.StringUtils;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Optional;
+import java.util.stream.Stream;
+
+public class OSReleaseUtil {
+
+    private static final Path OS_RELEASE_PATH = Path.of("/etc/os-release");
+
+    private OSReleaseUtil() {}
+
+    /**
+     * Finds and parses the VERSION_ID entry in the /etc/os-release file
+     *
+     * @return the VERSION_ID value
+     */
+    public static String getVersionId() {
+        return getVersionId(OS_RELEASE_PATH);
+    }
+
+    static String getVersionId(Path osReleasePath) {
+        String versionId = "UNKNOWN";
+
+        if (Files.exists(osReleasePath)) {
+            try (Stream<String> lines = Files.lines(osReleasePath)) {
+                Optional<String> versionIdOptional = lines.filter(line -> StringUtils.startsWith(line, "VERSION_ID")).findFirst();
+                if (versionIdOptional.isPresent()) {
+                    String versionIdLine = versionIdOptional.get().replace("\"", "");
+                    versionId = versionIdLine.substring(versionIdLine.indexOf("=") + 1);
+                }
+            } catch (Exception e) {
+                // ignore
+            }
+        }
+        return versionId;
+    }
+
+    /**
+     * Uses the VERSION_ID entry in the /etc/os-release file to determine the major OS version
+     *
+     * @return the major OS version
+     */
+    public static String getMajorVersion() {
+        return getMajorVersion(OS_RELEASE_PATH);
+    }
+
+    static String getMajorVersion(Path osReleasePath) {
+        return String.format("%.0f", Float.parseFloat(getVersionId(osReleasePath)));
+    }
+
+    /**
+     * Use the /etc/os-release file to determine if the OS is Ubuntu
+     *
+     * @return true if ubuntu is found, false otherwise
+     */
+    public static boolean isUbuntu() {
+        return isUbuntu(OS_RELEASE_PATH);
+    }
+
+    static boolean isUbuntu(Path osReleasePath) {
+        if (Files.exists(osReleasePath)) {
+            try (Stream<String> lines = Files.lines(osReleasePath)) {
+                return lines.anyMatch(s -> StringUtils.containsIgnoreCase(s, "ubuntu"));
+            } catch (Exception e) {
+                // ignore
+            }
+        }
+        return false;
+    }
+}

src/test/java/emissary/util/os/OSReleaseUtilTest.java

@@ -0,0 +1,44 @@
+package emissary.util.os;
+
+import emissary.util.io.ResourceReader;
+
+import org.junit.jupiter.api.Test;
+
+import java.nio.file.Path;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class OSReleaseUtilTest {
+
+    @Test
+    void testGetVersionId() throws Exception {
+        ResourceReader rr = new ResourceReader();
+
+        assertEquals("7", OSReleaseUtil.getVersionId(Path.of(rr.getResource(rr.getResourceName(this.getClass().getPackage(), "centos7")).toURI())));
+        assertEquals("8.10", OSReleaseUtil.getVersionId(Path.of(rr.getResource(rr.getResourceName(this.getClass().getPackage(), "rhel8")).toURI())));
+        assertEquals("20.04",
+                OSReleaseUtil.getVersionId(Path.of(rr.getResource(rr.getResourceName(this.getClass().getPackage(), "ubuntu")).toURI())));
+    }
+
+    @Test
+    void testGetMajorVersion() throws Exception {
+        ResourceReader rr = new ResourceReader();
+
+        assertEquals("7",
+                OSReleaseUtil.getMajorVersion(Path.of(rr.getResource(rr.getResourceName(this.getClass().getPackage(), "centos7")).toURI())));
+        assertEquals("8", OSReleaseUtil.getMajorVersion(Path.of(rr.getResource(rr.getResourceName(this.getClass().getPackage(), "rhel8")).toURI())));
+        assertEquals("20",
+                OSReleaseUtil.getMajorVersion(Path.of(rr.getResource(rr.getResourceName(this.getClass().getPackage(), "ubuntu")).toURI())));
+    }
+
+    @Test
+    void testIsUbuntu() throws Exception {
+        ResourceReader rr = new ResourceReader();
+
+        assertFalse(OSReleaseUtil.isUbuntu(Path.of(rr.getResource(rr.getResourceName(this.getClass().getPackage(), "centos7")).toURI())));
+        assertFalse(OSReleaseUtil.isUbuntu(Path.of(rr.getResource(rr.getResourceName(this.getClass().getPackage(), "rhel8")).toURI())));
+        assertTrue(OSReleaseUtil.isUbuntu(Path.of(rr.getResource(rr.getResourceName(this.getClass().getPackage(), "ubuntu")).toURI())));
+    }
+}

src/test/resources/emissary/util/os/centos7

@@ -0,0 +1,15 @@
+NAME="CentOS Linux"
+VERSION="7 (Core)"
+ID="centos"
+ID_LIKE="rhel fedora"
+VERSION_ID="7"
+PRETTY_NAME="CentOS Linux 7 (Core)"
+ANSI_COLOR="0;31"
+CPE_NAME="cpe:/o:centos:centos:7"
+HOME_URL="https://www.centos.org/"
+BUG_REPORT_URL="https://bugs.centos.org/"
+
+CENTOS_MANTISBT_PROJECT="CentOS-7"
+CENTOS_MANTISBT_PROJECT_VERSION="7"
+REDHAT_SUPPORT_PRODUCT="centos"
+REDHAT_SUPPORT_PRODUCT_VERSION="7"

src/test/resources/emissary/util/os/rhel8

@@ -0,0 +1,17 @@
+NAME="Red Hat Enterprise Linux"
+VERSION="8.10 (Ootpa)"
+ID="rhel"
+ID_LIKE="fedora"
+VERSION_ID="8.10"
+PLATFORM_ID="platform:el8"
+PRETTY_NAME="Red Hat Enterprise Linux 8.10 (Ootpa)"
+ANSI_COLOR="0;31"
+CPE_NAME="cpe:/o:redhat:enterprise_linux:8::baseos"
+HOME_URL="https://www.redhat.com/"
+DOCUMENTATION_URL="https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8"
+BUG_REPORT_URL="https://issues.redhat.com/"
+
+REDHAT_BUGZILLA_PRODUCT="Red Hat Enterprise Linux 8"
+REDHAT_BUGZILLA_PRODUCT_VERSION=8.10
+REDHAT_SUPPORT_PRODUCT="Red Hat Enterprise Linux"
+REDHAT_SUPPORT_PRODUCT_VERSION="8.10"

src/test/resources/emissary/util/os/ubuntu

@@ -0,0 +1,8 @@
+NAME="Ubuntu"
+VERSION="20.04.3 LTS (Focal Fossa)"
+ID="ubuntu"
+ID_LIKE="debian"
+VERSION_ID="20.04"
+PRETTY_NAME="Ubuntu 20.04.3 LTS"
+HOME_URL="https://www.ubuntu.com/"
+BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"