fix: docker hosts and ports env variable wrongly used (#2050)

* fix: docker hosts and ports env variable wrongly used

* fix: ci issues

packages/docker/src/singleton.ts

@@ -0,0 +1,53 @@
+import Docker from "dockerode";
+
+import { env } from "./env";
+
+export interface DockerInstance {
+  host: string;
+  instance: Docker;
+}
+
+export class DockerSingleton {
+  private static instances: DockerInstance[] | null = null;
+
+  private createInstances() {
+    const hostVariable = env.DOCKER_HOSTNAMES;
+    const portVariable = env.DOCKER_PORTS;
+    if (hostVariable === undefined || portVariable === undefined) {
+      return [{ host: "socket", instance: new Docker() }];
+    }
+    const hostnames = hostVariable.split(",");
+    const ports = portVariable.split(",");
+
+    if (hostnames.length !== ports.length) {
+      throw new Error("The number of hosts and ports must match");
+    }
+
+    return hostnames.map((host, i) => {
+      // Check above ensures that ports[i] is not undefined
+      // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+      const port = ports[i]!;
+
+      return {
+        host: `${host}:${port}`,
+        instance: new Docker({
+          host,
+          port: parseInt(port, 10),
+        }),
+      };
+    });
+  }
+
+  public static findInstance(host: string): DockerInstance | undefined {
+    return this.instances?.find((instance) => instance.host === host);
+  }
+
+  public static getInstances(): DockerInstance[] {
+    if (this.instances) {
+      return this.instances;
+    }
+
+    this.instances = new DockerSingleton().createInstances();
+    return this.instances;
+  }
+}