From 4ff8daafc451c1c54029180d40965ffbcf936481 Mon Sep 17 00:00:00 2001
From: "alexei.dolgolyov" <dolgolyov.alexei@gmail.com>
Date: Sun, 5 Apr 2026 02:42:31 +0300
Subject: [PATCH] fix: reconcile instance status with Docker on list, add
 IsContainerRunning

---
 internal/api/instances.go    | 21 +++++++++++++++++++++
 internal/docker/container.go |  9 +++++++++
 2 files changed, 30 insertions(+)

diff --git a/internal/api/instances.go b/internal/api/instances.go
index edf4a64..a9bcb43 100644
--- a/internal/api/instances.go
+++ b/internal/api/instances.go
@@ -33,6 +33,27 @@ func (s *Server) listInstances(w http.ResponseWriter, r *http.Request) {
 		respondError(w, http.StatusInternalServerError, "internal server error")
 		return
 	}
+
+	// Reconcile instance statuses with Docker's actual state.
+	ctx := r.Context()
+	for i, inst := range instances {
+		if inst.ContainerID == "" || inst.Status == "removing" {
+			continue
+		}
+		running, err := s.docker.IsContainerRunning(ctx, inst.ContainerID)
+		if err != nil {
+			continue // Docker unreachable, keep stored status.
+		}
+		actualStatus := "stopped"
+		if running {
+			actualStatus = "running"
+		}
+		if inst.Status != actualStatus {
+			instances[i].Status = actualStatus
+			_ = s.store.UpdateInstanceStatus(inst.ID, actualStatus)
+		}
+	}
+
 	respondJSON(w, http.StatusOK, instances)
 }
 
diff --git a/internal/docker/container.go b/internal/docker/container.go
index c835766..352a781 100644
--- a/internal/docker/container.go
+++ b/internal/docker/container.go
@@ -246,6 +246,15 @@ func (c *Client) ListContainers(ctx context.Context, labelFilters map[string]str
 	return result, nil
 }
 
+// IsContainerRunning checks if a container is in the "running" state.
+func (c *Client) IsContainerRunning(ctx context.Context, containerID string) (bool, error) {
+	inspectResult, err := c.api.ContainerInspect(ctx, containerID, client.ContainerInspectOptions{})
+	if err != nil {
+		return false, err
+	}
+	return inspectResult.Container.State != nil && inspectResult.Container.State.Running, nil
+}
+
 // InspectContainerPort returns the host port mapped to a given container port.
 // This is useful after starting a container with auto-assigned ports.
 func (c *Client) InspectContainerPort(ctx context.Context, containerID string, containerPort string) (uint16, error) {