Added the ability to configure an Operator's Docker host using a YAML file

src/core/Synapse.Core/Resources/DockerRuntimeConfiguration.cs

@@ -84,7 +84,7 @@ public DockerRuntimeConfiguration()
     /// Gets/sets the configuration of the host to use when running runner containers
     /// </summary>
     [DataMember(Order = 5, Name = "hostConfig"), JsonPropertyOrder(5), JsonPropertyName("hostConfig"), YamlMember(Order = 5, Alias = "hostConfig")]
-    public virtual HostConfig? HostConfig { get; set; }
+    public virtual HostConfig? HostConfig { get; set; } = LoadHostConfig();
 
     /// <summary>
     /// Gets/sets the path to the directory that contains the secrets to mount in runner containers on a per workflow configuration basis
@@ -110,4 +110,16 @@ public static Config LoadContainerTemplate()
         return YamlSerializer.Default.Deserialize<Config>(yaml)!;
     }
 
+    /// <summary>
+    /// Loads the host configuration to use when running runner containers
+    /// </summary>
+    /// <returns>The host configuration to use when running runner containers, or <c>null</c> if no host configuration is defined</returns>
+    public static HostConfig? LoadHostConfig()
+    {
+        var hostConfigFilePath = Environment.GetEnvironmentVariable(SynapseDefaults.EnvironmentVariables.Runtime.Docker.Host);
+        if (string.IsNullOrWhiteSpace(hostConfigFilePath) || !File.Exists(hostConfigFilePath)) return null;
+        var yaml = File.ReadAllText(hostConfigFilePath);
+        return YamlSerializer.Default.Deserialize<HostConfig>(yaml);
+    }
+
 }

src/core/Synapse.Core/SynapseDefaults.cs

@@ -730,6 +730,10 @@ public static class Docker
                 /// </summary>
                 public const string Container = Prefix + "CONTAINER";
                 /// <summary>
+                /// Gets the environment variable used to specify the YAML file used to configure the Docker runner host
+                /// </summary>
+                public const string Host = Prefix + "HOST";
+                /// <summary>
                 /// Gets the environment variable used to configure the network runner containers should be connected to
                 /// </summary>
                 public const string Network = Prefix + "NETWORK";