docker-modem-mock


!Coverage

A mock implementation of docker-modem for testing purposes. This package allows you to mock Docker API calls in your tests when your code interacts with Docker (e.g., creating containers), but you don't need a real Docker daemon or to test the actual container contents.

Features

- Image Management: Pulling, building, listing, inspecting, and deleting images.
- Container Lifecycle: Creating, starting, stopping, listing, and inspecting containers.
- Fixture-based Responses: Use pre-recorded or custom fixtures to simulate Docker API responses for complex operations like pull and build.
- Dockerode Integration: Seamlessly works with dockerode by replacing its underlying modem.

Installation

``bash
npm install docker-modem-mock --save-dev
`

Usage

$3

`typescript
import Docker from "dockerode";
import { ModemMock, Fixtures } from "docker-modem-mock";

const docker = new Docker({
modem: new ModemMock({
mockFixtures: Fixtures.fromPath("./test/fixtures")
})
});
`

$3

`typescript
const stream = await docker.pull("node:18");
stream.on("data", (chunk) => console.log(chunk.toString()));
stream.on("end", () => console.log("Pull complete"));
`

$3

`typescript
const stream = await docker.buildImage({
context: "./path/to/context",
src: ["Dockerfile", "index.js"]
}, {
t: "my-image:latest"
});
`

$3

`typescript
const container = await docker.createContainer({
Image: "node:18",
name: "my-container"
});

await container.start();
const inspect = await container.inspect();

console.log(inspect.State.Status); // "running"

await container.stop();
`

Fixtures Structure

The mock relies on a specific directory structure for fixtures:

- records/{version}/image/{imageName}/{tag}.json: JSON file containing image inspection data.
- records/{version}/pull/{imageName}/{tag}.jsonl: JSONL file containing streaming output for image pull.
- records/{version}/build-{builderVersion}/{imageName}/{tag}.jsonl: JSONL file containing streaming output for image build.

Fixtures recorder

Currently, fixtures must be recorded manually; a dedicated command for this will be created in the future.

For now, you can use the following script for this purpose:

`typescript
import Docker from "dockerode";
import { ModemRecorder, Fixtures } from "docker-modem-mock";
import Path from "path";

const docker = new Docker({
modem: new ModemRecorder({
recordFixtures: Fixtures.fromPath(Path.resolve("./your-fixtures-dir")),
// Docker modem setting:
socketPath: "/var/run/docker.sock"
})
});

const image = docker.getImage("node:23");

await image.remove().catch(() => undefined);

const stream = await docker.pull("node:23");

stream.on("data", (chunk) => process.stdout.write(chunk.toString()));
stream.on("end", async () => {
console.log(await image.inspect());
});
`

This script will record the pull response for the image to the your-fixtures-dir/records/v1/pull/node/23.jsonl file.

API

$3

Inherits from Modem.

- constructor(options: Options)
- mockFixtures: Optional Fixtures instance to load initial data.
- registerFixtures(fixtures: Fixtures): Registers additional fixtures.
- reset(): Resets the internal state (containers and images).

$3

- static fromPath(path: string): Creates a Fixtures instance from a filesystem path.
- static fromFS(fs: FileSystem): Creates a Fixtures instance from a docker-modem-mock` FileSystem.

License

MIT