client/fingerprint/java: improve java version string regex matching

This PR improves the regular expression used for matching the java
version string, which varies a lot depending on the java vendor and
version.

These are the example strings we now test for:

java version "1.7.0_80"
openjdk version "11.0.1" 2018-10-16
openjdk version "11.0.1" 2018-10-16
java version "1.6.0_36"
openjdk version "1.8.0_192"
openjdk 11.0.11 2021-04-20 LTS

The last one is a new test added on behalf of #6081, which is
still broken on today's CentOS 7 default JDK package.

openjdk 11.0.11 2021-04-20 LTS
OpenJDK Runtime Environment 18.9 (build 11.0.11+9-LTS)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.11+9-LTS, mixed mode, sharing)

==> Evaluation "21c6caf7" finished with status "complete" but failed to place all allocations:
    Task Group "example" (failed to place 1 allocation):
      * Constraint "${driver.java.version} >= 11.0.0": 1 nodes excluded by filter
    Evaluation "2b737d48" waiting for additional capacity to place remainder

Fixes #6081

drivers/java/driver.go

@@ -356,7 +356,7 @@ func (d *Driver) buildFingerprint() *drivers.Fingerprint {
 		}
 	}
 
-	version, runtime, vm, err := javaVersionInfo()
+	version, jdkJRE, vm, err := javaVersionInfo()
 	if err != nil {
 		// return no error, as it isn't an error to not find java, it just means we
 		// can't use it.
@@ -367,7 +367,7 @@ func (d *Driver) buildFingerprint() *drivers.Fingerprint {
 
 	fp.Attributes[driverAttr] = pstructs.NewBoolAttribute(true)
 	fp.Attributes[driverVersionAttr] = pstructs.NewStringAttribute(version)
-	fp.Attributes["driver.java.runtime"] = pstructs.NewStringAttribute(runtime)
+	fp.Attributes["driver.java.runtime"] = pstructs.NewStringAttribute(jdkJRE)
 	fp.Attributes["driver.java.vm"] = pstructs.NewStringAttribute(vm)
 
 	return fp

drivers/java/utils.go

@@ -50,6 +50,10 @@ func javaVersionInfo() (version, runtime, vm string, err error) {
 	return
 }
 
+var (
+	javaVersionRe = regexp.MustCompile(`([.\d_]+)`)
+)
+
 func parseJavaVersionOutput(infoString string) (version, runtime, vm string) {
 	infoString = strings.TrimSpace(infoString)
 
@@ -65,8 +69,7 @@ func parseJavaVersionOutput(infoString string) (version, runtime, vm string) {
 
 	versionString := strings.TrimSpace(lines[0])
 
-	re := regexp.MustCompile(`version "([^"]*)"`)
-	if match := re.FindStringSubmatch(lines[0]); len(match) == 2 {
+	if match := javaVersionRe.FindStringSubmatch(versionString); len(match) == 2 {
 		versionString = match[1]
 	}
 

drivers/java/utils_test.go

@@ -8,11 +8,6 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-const oracleJDKOutput = `java version "1.7.0_80"
-Java(TM) SE Runtime Environment (build 1.7.0_80-b15)
-Java HotSpot(TM) 64-Bit Server VM (build 24.80-b11, mixed mode)
-`
-
 func TestDriver_parseJavaVersionOutput(t *testing.T) {
 	cases := []struct {
 		name    string
@@ -23,7 +18,9 @@ func TestDriver_parseJavaVersionOutput(t *testing.T) {
 	}{
 		{
 			"OracleJDK",
-			oracleJDKOutput,
+			`java version "1.7.0_80"
+			Java(TM) SE Runtime Environment (build 1.7.0_80-b15)
+			Java HotSpot(TM) 64-Bit Server VM (build 24.80-b11, mixed mode)`,
 			"1.7.0_80",
 			"Java(TM) SE Runtime Environment (build 1.7.0_80-b15)",
 			"Java HotSpot(TM) 64-Bit Server VM (build 24.80-b11, mixed mode)",
@@ -69,14 +66,22 @@ func TestDriver_parseJavaVersionOutput(t *testing.T) {
 			"OpenJDK Runtime Environment (build 1.8.0_192-b12_openj9)",
 			"Eclipse OpenJ9 VM (build openj9-0.11.0, JRE 1.8.0 Linux amd64-64-Bit Compressed References",
 		},
+		{
+			"OpenJDK on CentOS 7",
+			`openjdk 11.0.11 2021-04-20 LTS
+			OpenJDK Runtime Environment 18.9 (build 11.0.11+9-LTS)
+			OpenJDK 64-Bit Server VM 18.9 (build 11.0.11+9-LTS, mixed mode, sharing)`,
+			`11.0.11`,
+			`OpenJDK Runtime Environment 18.9 (build 11.0.11+9-LTS)`,
+			`OpenJDK 64-Bit Server VM 18.9 (build 11.0.11+9-LTS, mixed mode, sharing)`,
+		},
 	}
 
 	for _, c := range cases {
 		t.Run(c.name, func(t *testing.T) {
-			version, runtime, vm := parseJavaVersionOutput(c.output)
-
-			require.Equal(t, c.version, version)
-			require.Equal(t, c.runtime, runtime)
+			jdkVersion, jdkJRE, vm := parseJavaVersionOutput(c.output)
+			require.Equal(t, c.version, jdkVersion)
+			require.Equal(t, c.runtime, jdkJRE)
 			require.Equal(t, c.vm, vm)
 		})
 	}
@@ -94,13 +99,16 @@ func TestDriver_javaVersionInfo(t *testing.T) {
 
 	javaVersionCommand = []string{
 		"/bin/sh", "-c",
-		fmt.Sprintf("printf '%%s\n' '%s' >/dev/stderr", oracleJDKOutput),
+		fmt.Sprintf("printf '%%s\n' '%s' >/dev/stderr",
+			`java version "1.7.0_80"
+			Java(TM) SE Runtime Environment (build 1.7.0_80-b15)
+			Java HotSpot(TM) 64-Bit Server VM (build 24.80-b11, mixed mode)`),
 	}
 
-	version, runtime, vm, err := javaVersionInfo()
+	version, jdkJRE, vm, err := javaVersionInfo()
 	require.NoError(t, err)
 	require.Equal(t, "1.7.0_80", version)
-	require.Equal(t, "Java(TM) SE Runtime Environment (build 1.7.0_80-b15)", runtime)
+	require.Equal(t, "Java(TM) SE Runtime Environment (build 1.7.0_80-b15)", jdkJRE)
 	require.Equal(t, "Java HotSpot(TM) 64-Bit Server VM (build 24.80-b11, mixed mode)", vm)
 
 }
@@ -120,10 +128,10 @@ func TestDriver_javaVersionInfo_UnexpectedOutput(t *testing.T) {
 		fmt.Sprintf("printf '%%s\n' '%s' >/dev/stderr", "unexpected java -version output"),
 	}
 
-	version, runtime, vm, err := javaVersionInfo()
+	version, jdkJRE, vm, err := javaVersionInfo()
 	require.NoError(t, err)
 	require.Equal(t, "", version)
-	require.Equal(t, "", runtime)
+	require.Equal(t, "", jdkJRE)
 	require.Equal(t, "", vm)
 }
 
@@ -142,11 +150,11 @@ func TestDriver_javaVersionInfo_JavaVersionFails(t *testing.T) {
 		"exit 127",
 	}
 
-	version, runtime, vm, err := javaVersionInfo()
+	version, jdkJRE, vm, err := javaVersionInfo()
 	require.Error(t, err)
 	require.Contains(t, err.Error(), "failed to check java version")
 
 	require.Equal(t, "", version)
-	require.Equal(t, "", runtime)
+	require.Equal(t, "", jdkJRE)
 	require.Equal(t, "", vm)
 }