feat(versions): record own build info/version as properties, validate server version

pom.xml

@@ -104,8 +104,12 @@
   <maven-source-plugin.version>3.3.1</maven-source-plugin.version>
   <maven-javadoc-plugin.version>3.10.1</maven-javadoc-plugin.version>
   <jreleaser-maven-plugin.version>1.14.0</jreleaser-maven-plugin.version>
+  <org.codehaus.mojo.exec.plugin.version>3.4.1</org.codehaus.mojo.exec.plugin.version>
 
   <shade.prefix>io.cryostat.agent.shaded</shade.prefix>
+
+  <cryostat.server.version.min>4.0.0</cryostat.server.version.min>
+  <cryostat.server.version.max>5.0.0</cryostat.server.version.max>
 </properties>
 
 <dependencyManagement>
@@ -299,6 +303,29 @@
         </archive>
       </configuration>
     </plugin>
+    <plugin>
+      <groupId>org.codehaus.mojo</groupId>
+      <artifactId>exec-maven-plugin</artifactId>
+      <version>${org.codehaus.mojo.exec.plugin.version}</version>
+      <executions>
+        <execution>
+          <id>generate-git-version</id>
+          <phase>generate-resources</phase>
+          <goals>
+            <goal>exec</goal>
+          </goals>
+          <configuration>
+            <executable>git</executable>
+            <arguments>
+              <argument>rev-parse</argument>
+              <argument>--verify</argument>
+              <argument>HEAD</argument>
+            </arguments>
+            <outputFile>${project.build.directory}/classes/META-INF/gitinfo</outputFile>
+          </configuration>
+        </execution>
+      </executions>
+    </plugin>
     <plugin>
       <groupId>org.apache.maven.plugins</groupId>
       <artifactId>maven-shade-plugin</artifactId>

src/main/java/io/cryostat/agent/Agent.java

@@ -38,6 +38,7 @@
 import javax.inject.Singleton;
 
 import io.cryostat.agent.ConfigModule.URIRange;
+import io.cryostat.agent.VersionInfo.Semver;
 import io.cryostat.agent.harvest.Harvester;
 import io.cryostat.agent.insights.InsightsAgentHelper;
 import io.cryostat.agent.model.PluginInfo;
@@ -49,6 +50,7 @@
 import com.sun.tools.attach.VirtualMachine;
 import com.sun.tools.attach.VirtualMachineDescriptor;
 import dagger.Component;
+import org.apache.commons.lang3.tuple.Pair;
 import org.eclipse.microprofile.config.Config;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -155,7 +157,6 @@ public static void agentmain(String args, Instrumentation instrumentation) {
         Thread t =
                 new Thread(
                         () -> {
-                            log.info("Cryostat Agent starting...");
                             agent.accept(aa);
                         });
         t.setDaemon(true);
@@ -200,12 +201,30 @@ static URI selfJarLocation() throws URISyntaxException {
 
     @Override
     public void accept(AgentArgs args) {
-        args.getProperties()
-                .forEach(
-                        (k, v) -> {
-                            log.trace("Set system property {} = {}", k, v);
-                            System.setProperty(k, v);
-                        });
+        Map<String, String> properties = new HashMap<>();
+        properties.putAll(args.getProperties());
+        properties.put("build.git.commit-hash", new BuildInfo().getGitInfo().getHash());
+        Semver agentVersion = Semver.UNKNOWN;
+        Pair<Semver, Semver> serverVersionRange = Pair.of(Semver.UNKNOWN, Semver.UNKNOWN);
+        try {
+            VersionInfo versionInfo = VersionInfo.load();
+            serverVersionRange = Pair.of(versionInfo.getServerMin(), versionInfo.getServerMax());
+            agentVersion = versionInfo.getAgentVersion();
+            properties.putAll(versionInfo.asMap());
+        } catch (IOException ioe) {
+            log.warn("Unable to read versions.properties file", ioe);
+        }
+        log.info(
+                "Cryostat Agent version {} (for Cryostat server version range [{}, {}) )"
+                        + " starting...",
+                agentVersion,
+                serverVersionRange.getLeft(),
+                serverVersionRange.getRight());
+        properties.forEach(
+                (k, v) -> {
+                    log.trace("Set system property {} = {}", k, v);
+                    System.setProperty(k, v);
+                });
         AgentExitHandler agentExitHandler = null;
         try {
             final Client client = DaggerAgent_Client.builder().build();

src/main/java/io/cryostat/agent/BuildInfo.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright The Cryostat Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.cryostat.agent;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
+
+import io.cryostat.agent.util.ResourcesUtil;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+// FIXME this is adapted from Cryostat. Extract this to a reusable utility in libcryostat?
+public class BuildInfo {
+
+    private static Logger log = LoggerFactory.getLogger(BuildInfo.class);
+    private static final String RESOURCE_LOCATION = "META-INF/gitinfo";
+
+    private final GitInfo gitinfo = new GitInfo();
+
+    public GitInfo getGitInfo() {
+        return gitinfo;
+    }
+
+    public static class GitInfo {
+        public String getHash() {
+            try (BufferedReader br =
+                    new BufferedReader(
+                            new InputStreamReader(
+                                    ResourcesUtil.getResourceAsStream(RESOURCE_LOCATION),
+                                    StandardCharsets.UTF_8))) {
+                return br.lines()
+                        .findFirst()
+                        .orElseThrow(
+                                () ->
+                                        new IllegalStateException(
+                                                String.format(
+                                                        "Resource file %s is empty",
+                                                        RESOURCE_LOCATION)))
+                        .trim();
+            } catch (Exception e) {
+                log.warn("Version retrieval exception", e);
+                return "unknown";
+            }
+        }
+    }
+}

src/main/java/io/cryostat/agent/CryostatClient.java

@@ -44,6 +44,7 @@
 import io.cryostat.agent.model.DiscoveryNode;
 import io.cryostat.agent.model.PluginInfo;
 import io.cryostat.agent.model.RegistrationInfo;
+import io.cryostat.agent.model.ServerHealth;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.core.type.TypeReference;
@@ -111,6 +112,22 @@ public class CryostatClient {
         log.info("Using Cryostat baseuri {}", baseUri);
     }
 
+    public CompletableFuture<ServerHealth> serverHealth() {
+        HttpGet req = new HttpGet(baseUri.resolve("/health"));
+        log.trace("{}", req);
+        return supply(req, res -> logResponse(req, res))
+                .thenApply(
+                        res -> {
+                            try (InputStream is = res.getEntity().getContent()) {
+                                return mapper.readValue(is, ServerHealth.class);
+                            } catch (IOException e) {
+                                log.error("Unable to parse response as JSON", e);
+                                throw new RegistrationException(e);
+                            }
+                        })
+                .whenComplete((v, t) -> req.reset());
+    }
+
     public CompletableFuture<Boolean> checkRegistration(PluginInfo pluginInfo) {
         if (!pluginInfo.isInitialized()) {
             return CompletableFuture.completedFuture(false);

src/main/java/io/cryostat/agent/Registration.java

@@ -15,6 +15,7 @@
  */
 package io.cryostat.agent;
 
+import java.io.IOException;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.net.UnknownHostException;
@@ -33,6 +34,7 @@
 import java.util.function.Consumer;
 import java.util.stream.Collectors;
 
+import io.cryostat.agent.VersionInfo.Semver;
 import io.cryostat.agent.model.DiscoveryNode;
 import io.cryostat.agent.model.PluginInfo;
 import io.cryostat.agent.util.StringUtils;
@@ -197,6 +199,29 @@ void tryRegister() {
             return;
         }
         try {
+            cryostat.serverHealth()
+                    .thenAccept(
+                            health -> {
+                                Semver cryostatSemver = health.cryostatSemver();
+                                log.debug(
+                                        "Connected to Cryostat server: version {} , build {}",
+                                        cryostatSemver,
+                                        health.buildInfo().git().hash());
+                                try {
+                                    VersionInfo version = VersionInfo.load();
+                                    if (!version.validateServerVersion(cryostatSemver)) {
+                                        log.warn(
+                                                "Cryostat server version {} is outside of expected"
+                                                        + " range [{}, {})",
+                                                cryostatSemver,
+                                                version.getServerMin(),
+                                                version.getServerMax());
+                                    }
+                                } catch (IOException ioe) {
+                                    log.error("Unable to read versions.properties file", ioe);
+                                }
+                            })
+                    .get();
             URI credentialedCallback =
                     new URIBuilder(callback)
                             .setUserInfo("storedcredentials", String.valueOf(credentialId))