refactor(compute/api): Do not suspend in compute API

This change updates the API interface of the OpenDC Compute service to
not suspend execution using Kotlin Coroutines.

The suspending modifiers were introduced in case the ComputeClient would
communicate with the service over a network connection. However, the main
use-case has been together with the ComputeService, where the suspending
modifiers only frustrate the user experience when writing experiments.

Furthermore, with the advent of Project Loom, it is not necessarily a
problem to block the (virtual) thread during network communications.

6 files changed, 19 insertions, 41 deletions

diff --git a/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/ComputeClient.kt b/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/ComputeClient.kt
index 577fbc73..c26d0b8b 100644
--- a/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/ComputeClient.kt
+++ b/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/ComputeClient.kt
@@ -31,14 +31,14 @@ public interface ComputeClient : AutoCloseable {
     /**
      * Obtain the list of [Flavor]s accessible by the requesting user.
      */
-    public suspend fun queryFlavors(): List<Flavor>
+    public fun queryFlavors(): List<Flavor>
 
     /**
      * Obtain a [Flavor] by its unique identifier.
      *
      * @param id The identifier of the flavor.
      */
-    public suspend fun findFlavor(id: UUID): Flavor?
+    public fun findFlavor(id: UUID): Flavor?
 
     /**
      * Create a new [Flavor] instance at this compute service.
@@ -49,7 +49,7 @@ public interface ComputeClient : AutoCloseable {
      * @param labels The identifying labels of the image.
      * @param meta The non-identifying meta-data of the image.
      */
-    public suspend fun newFlavor(
+    public fun newFlavor(
         name: String,
         cpuCount: Int,
         memorySize: Long,
@@ -60,14 +60,14 @@ public interface ComputeClient : AutoCloseable {
     /**
      * Obtain the list of [Image]s accessible by the requesting user.
      */
-    public suspend fun queryImages(): List<Image>
+    public fun queryImages(): List<Image>
 
     /**
      * Obtain a [Image] by its unique identifier.
      *
      * @param id The identifier of the image.
      */
-    public suspend fun findImage(id: UUID): Image?
+    public fun findImage(id: UUID): Image?
 
     /**
      * Create a new [Image] instance at this compute service.
@@ -76,7 +76,7 @@ public interface ComputeClient : AutoCloseable {
      * @param labels The identifying labels of the image.
      * @param meta The non-identifying meta-data of the image.
      */
-    public suspend fun newImage(
+    public fun newImage(
         name: String,
         labels: Map<String, String> = emptyMap(),
         meta: Map<String, Any> = emptyMap()
@@ -85,14 +85,14 @@ public interface ComputeClient : AutoCloseable {
     /**
      * Obtain the list of [Server]s accessible by the requesting user.
      */
-    public suspend fun queryServers(): List<Server>
+    public fun queryServers(): List<Server>
 
     /**
      * Obtain a [Server] by its unique identifier.
      *
      * @param id The identifier of the server.
      */
-    public suspend fun findServer(id: UUID): Server?
+    public fun findServer(id: UUID): Server?
 
     /**
      * Create a new [Server] instance at this compute service.
@@ -104,7 +104,7 @@ public interface ComputeClient : AutoCloseable {
      * @param meta The non-identifying meta-data of the server.
      * @param start A flag to indicate that the server should be started immediately.
      */
-    public suspend fun newServer(
+    public fun newServer(
         name: String,
         image: Image,
         flavor: Flavor,
diff --git a/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Flavor.kt b/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Flavor.kt
index 5f511f91..d76e0fba 100644
--- a/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Flavor.kt
+++ b/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Flavor.kt
@@ -36,9 +36,4 @@ public interface Flavor : Resource {
      * The amount of RAM available to the server (in MB).
      */
     public val memorySize: Long
-
-    /**
-     * Delete the flavor instance.
-     */
-    public suspend fun delete()
 }
diff --git a/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Image.kt b/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Image.kt
index 83e63b81..c4a04b96 100644
--- a/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Image.kt
+++ b/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Image.kt
@@ -25,9 +25,4 @@ package org.opendc.compute.api
 /**
  * An image containing a bootable operating system that can directly be executed by physical or virtual server.
  */
-public interface Image : Resource {
-    /**
-     * Delete the image instance.
-     */
-    public suspend fun delete()
-}
+public interface Image : Resource
diff --git a/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Resource.kt b/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Resource.kt
index 08120848..58082130 100644
--- a/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Resource.kt
+++ b/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Resource.kt
@@ -49,7 +49,12 @@ public interface Resource {
     public val meta: Map<String, Any>
 
     /**
-     * Refresh the local state of the resource.
+     * Reload the attributes of the resource.
      */
-    public suspend fun refresh()
+    public fun reload()
+
+    /**
+     * Delete the resource.
+     */
+    public fun delete()
 }
diff --git a/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Server.kt b/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Server.kt
index 64b73d0b..b4cc5129 100644
--- a/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Server.kt
+++ b/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/Server.kt
@@ -50,27 +50,13 @@ public interface Server : Resource {
 
     /**
      * Request the server to be started.
-     *
-     * This method is guaranteed to return after the request was acknowledged, but might return before the server was
-     * started.
      */
-    public suspend fun start()
+    public fun start()
 
     /**
      * Request the server to be stopped.
-     *
-     * This method is guaranteed to return after the request was acknowledged, but might return before the server was
-     * stopped.
-     */
-    public suspend fun stop()
-
-    /**
-     * Request the server to be deleted.
-     *
-     * This method is guaranteed to return after the request was acknowledged, but might return before the server was
-     * deleted.
      */
-    public suspend fun delete()
+    public fun stop()
 
     /**
      * Register the specified [ServerWatcher] to watch the state of the server.
diff --git a/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/ServerWatcher.kt b/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/ServerWatcher.kt
index 48a17b30..cf995fc3 100644
--- a/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/ServerWatcher.kt
+++ b/opendc-compute/opendc-compute-api/src/main/kotlin/org/opendc/compute/api/ServerWatcher.kt
@@ -29,9 +29,6 @@ public interface ServerWatcher {
     /**
      * This method is invoked when the state of a [Server] changes.
      *
-     * Note that the state of [server] might not reflect the state as reported by the invocation, as a call to
-     * [Server.refresh] is required to update its state.
-     *
      * @param server The server whose state has changed.
      * @param newState The new state of the server.
      */