initial copy

s8n-runtime/WorkflowRuntimeRunner.cs

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+namespace s8n_runtime;
+
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+public class WorkflowRuntimeRunner
+{
+    private static readonly JsonSerializerOptions serializerOptions = new(JsonSerializerDefaults.Web)
+    {
+        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
+    };
+    public static async Task<int> Main<TWorkflow>(string[] args, bool silent = false) where TWorkflow : WorkflowRuntime
+    {
+        if (!silent) Console.WriteLine("Starting workflow...");
+
+        var cts = new CancellationTokenSource();
+        Console.CancelKeyPress += (s, e) =>
+        {
+            if (!silent) Console.WriteLine("Canceling...");
+            cts.Cancel();
+            e.Cancel = true;
+        };
+
+        async Task<string?> FindWorkflowJsonFile()
+        {
+            if (args.FirstOrDefault(a => a.EndsWith("workflow.json")) is string jsonArg) return jsonArg;
+            if (Environment.GetEnvironmentVariable("WORKFLOW_FILE") is string workflowFile) return workflowFile;
+
+            var testPath = Path.GetFullPath("workflow.json");
+            if (File.Exists(testPath))
+            {
+                return testPath;
+            }
+            return null;
+
+        }
+
+        var filePath = await FindWorkflowJsonFile();
+        TWorkflow runtime;
+        if (filePath == null)
+        {
+            runtime = Activator.CreateInstance<TWorkflow>();
+        }
+        else
+        {
+            runtime = JsonSerializer.Deserialize<TWorkflow>(File.OpenRead(filePath), serializerOptions)!;
+        }
+        runtime.Prepare();
+
+        try
+        {
+            await runtime.RunAsync(cts.Token);
+        }
+        catch (TaskCanceledException)
+        {
+            if (!silent) Console.WriteLine("Canceled.");
+        }
+        finally
+        {
+            await runtime.OnStop();
+        }
+
+
+        if (runtime.StoreState == RuntimeStateStoreStrategy.WhenExit)
+        {
+            if (string.IsNullOrEmpty(filePath) is false)
+            {
+                JsonSerializer.Serialize(File.OpenWrite(filePath), runtime, serializerOptions);
+            }
+        }
+
+        if (!silent) Console.WriteLine("Workflow stopped.");
+        return 0;
+    }
+}