merge: Clean up compute service (v1)

This pull request is one in a series of changes that attempt to clean up the 
warts of the OpenDC Compute Service. These changes should make the
API more robust for future developments.

## Implementation Notes :hammer_and_pick:

* Do not suspend in compute API
* Expose state directly to clients
* Do not split interface and implementation

## External Dependencies :four_leaf_clover:

* N/A

## Breaking API Changes :warning:

* The methods of `ComputeClient` do not have the suspend modifier anymore.
* Changes to the classes of `ComputeClient` are now immediately visible on the server side.
   It is not necessary to call `refresh` anymore.
* `ComputeService` must be constructed via its builder class now.

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.
      */