added healthcheck command to client

gbcs-cli/src/main/kotlin/net/woggioni/gbcs/cli/GradleBuildCacheServerCli.kt

@@ -5,6 +5,7 @@ import net.woggioni.gbcs.cli.impl.GbcsCommand
 import net.woggioni.gbcs.cli.impl.commands.BenchmarkCommand
 import net.woggioni.gbcs.cli.impl.commands.ClientCommand
 import net.woggioni.gbcs.cli.impl.commands.GetCommand
+import net.woggioni.gbcs.cli.impl.commands.HealthCheckCommand
 import net.woggioni.gbcs.cli.impl.commands.PasswordHashCommand
 import net.woggioni.gbcs.cli.impl.commands.PutCommand
 import net.woggioni.gbcs.cli.impl.commands.ServerCommand
@@ -44,6 +45,7 @@ class GradleBuildCacheServerCli : GbcsCommand() {
                     addSubcommand(BenchmarkCommand())
                     addSubcommand(PutCommand())
                     addSubcommand(GetCommand())
+                    addSubcommand(HealthCheckCommand())
                 })
             System.exit(commandLine.execute(*args))
         }

gbcs-cli/src/main/kotlin/net/woggioni/gbcs/cli/impl/commands/BenchmarkCommand.kt

@@ -46,7 +46,7 @@ class BenchmarkCommand : GbcsCommand() {
             clientCommand.configuration.profiles[profileName]
                 ?: throw IllegalArgumentException("Profile $profileName does not exist in configuration")
         }
-        val client = GradleBuildCacheClient(profile)
+        GradleBuildCacheClient(profile).use { client ->
 
             val entryGenerator = sequence {
                 val random = Random(SecureRandom.getInstance("NativePRNGNonBlocking").nextLong())
@@ -133,3 +133,4 @@ class BenchmarkCommand : GbcsCommand() {
             }
         }
     }
+}

gbcs-cli/src/main/kotlin/net/woggioni/gbcs/cli/impl/commands/HealthCheckCommand.kt

@@ -0,0 +1,45 @@
+package net.woggioni.gbcs.cli.impl.commands
+
+import net.woggioni.gbcs.cli.impl.GbcsCommand
+import net.woggioni.gbcs.client.GradleBuildCacheClient
+import net.woggioni.gbcs.common.contextLogger
+import picocli.CommandLine
+import java.security.SecureRandom
+import kotlin.random.Random
+
+@CommandLine.Command(
+    name = "health",
+    description = ["Check server health"],
+    showDefaultValues = true
+)
+class HealthCheckCommand : GbcsCommand() {
+    private val log = contextLogger()
+
+    @CommandLine.Spec
+    private lateinit var spec: CommandLine.Model.CommandSpec
+
+    override fun run() {
+        val clientCommand = spec.parent().userObject() as ClientCommand
+        val profile = clientCommand.profileName.let { profileName ->
+            clientCommand.configuration.profiles[profileName]
+                ?: throw IllegalArgumentException("Profile $profileName does not exist in configuration")
+        }
+        GradleBuildCacheClient(profile).use { client ->
+            val random = Random(SecureRandom.getInstance("NativePRNGNonBlocking").nextLong())
+            val nonce = ByteArray(0xa0)
+            random.nextBytes(nonce)
+            client.healthCheck(nonce).thenApply { value ->
+                if(value == null) {
+                    throw IllegalStateException("Empty response from server")
+                }
+                for(i in 0 until nonce.size) {
+                    for(j in value.size - nonce.size until nonce.size) {
+                        if(nonce[i] != value[j]) {
+                            throw IllegalStateException("Server nonce does not match")
+                        }
+                    }
+                }
+            }.get()
+        }
+    }
+}

gbcs-client/src/main/kotlin/net/woggioni/gbcs/client/Client.kt

@@ -213,6 +213,25 @@ class GradleBuildCacheClient(private val profile: Configuration.Profile) : AutoC
         }
     }
 
+    fun healthCheck(nonce: ByteArray): CompletableFuture<ByteArray?> {
+        return executeWithRetry {
+            sendRequest(profile.serverURI, HttpMethod.TRACE, nonce)
+        }.thenApply {
+            val status = it.status()
+            if (it.status() != HttpResponseStatus.OK) {
+                throw HttpException(status)
+            } else {
+                it.content()
+            }
+        }.thenApply { maybeByteBuf ->
+            maybeByteBuf?.let {
+                val result = ByteArray(it.readableBytes())
+                it.getBytes(0, result)
+                result
+            }
+        }
+    }
+
     fun get(key: String): CompletableFuture<ByteArray?> {
         return executeWithRetry {
             sendRequest(profile.serverURI.resolve(key), HttpMethod.GET, null)