Follow symlinks when copying files into containers (#1235)

Author: cristianrgreco

docs/features/containers.md

@@ -160,6 +160,8 @@ container.copyContentToContainer([{
 container.copyArchiveToContainer(nodeReadable, "/some/nested/remotedir");
 ```
 
+When copying files, symbolic links in `source` are followed and the linked file content is copied into the container.
+
 An optional `mode` can be specified in octal for setting file permissions:
 
 ```js

packages/testcontainers/src/generic-container/generic-container.test.ts

@@ -6,6 +6,7 @@ import { PullPolicy } from "../utils/pull-policy";
 import {
   checkContainerIsHealthy,
   checkContainerIsHealthyUdp,
+  createTempSymlinkedFile,
   getDockerEventStream,
   getRunningContainerNames,
   waitForDockerEvent,
@@ -374,6 +375,23 @@ describe("GenericContainer", { timeout: 180_000 }, () => {
     expect((await container.exec(["cat", target])).output).toEqual(expect.stringContaining("hello world"));
   });
 
+  it("should follow symlink when copying file to container", async () => {
+    if (process.platform === "win32") {
+      return;
+    }
+
+    const content = `hello world ${new RandomUuid().nextUuid()}`;
+    const target = "/tmp/test.txt";
+    await using symlinkedFile = await createTempSymlinkedFile(content);
+    await using container = await new GenericContainer("cristianrgreco/testcontainer:1.1.14")
+      .withCopyFilesToContainer([{ source: symlinkedFile.symlink, target }])
+      .withExposedPorts(8080)
+      .start();
+
+    expect((await container.exec(["cat", target])).output).toEqual(expect.stringContaining(content));
+    expect((await container.exec(["sh", "-c", `[ -L ${target} ]`])).exitCode).toBe(1);
+  });
+
   it("should copy file to container with permissions", async () => {
     const source = path.resolve(fixtures, "docker", "test.txt");
     const target = "/tmp/test.txt";
@@ -399,6 +417,24 @@ describe("GenericContainer", { timeout: 180_000 }, () => {
     expect((await container.exec(["cat", target])).output).toEqual(expect.stringContaining("hello world"));
   });
 
+  it("should follow symlink when copying file to started container", async () => {
+    if (process.platform === "win32") {
+      return;
+    }
+
+    const content = `hello world ${new RandomUuid().nextUuid()}`;
+    const target = "/tmp/test.txt";
+    await using symlinkedFile = await createTempSymlinkedFile(content);
+    await using container = await new GenericContainer("cristianrgreco/testcontainer:1.1.14")
+      .withExposedPorts(8080)
+      .start();
+
+    await container.copyFilesToContainer([{ source: symlinkedFile.symlink, target }]);
+
+    expect((await container.exec(["cat", target])).output).toEqual(expect.stringContaining(content));
+    expect((await container.exec(["sh", "-c", `[ -L ${target} ]`])).exitCode).toBe(1);
+  });
+
   it("should copy directory to container", async () => {
     const source = path.resolve(fixtures, "docker");
     const target = "/tmp";

packages/testcontainers/src/generic-container/generic-container.ts

@@ -1,6 +1,7 @@
 import archiver from "archiver";
 import AsyncLock from "async-lock";
 import { Container, ContainerCreateOptions, HostConfig } from "dockerode";
+import { promises as fs } from "fs";
 import { Readable } from "stream";
 import { containerLog, hash, log, toNanos } from "../common";
 import { ContainerRuntimeClient, getContainerRuntimeClient, ImageName } from "../container-runtime";
@@ -179,7 +180,7 @@ export class GenericContainer implements TestContainer {
     }
 
     if (this.filesToCopy.length > 0 || this.directoriesToCopy.length > 0 || this.contentsToCopy.length > 0) {
-      const archive = this.createArchiveToCopyToContainer();
+      const archive = await this.createArchiveToCopyToContainer();
       archive.finalize();
       await client.container.putArchive(container, archive, "/");
     }
@@ -255,11 +256,17 @@ export class GenericContainer implements TestContainer {
     }
   }
 
-  private createArchiveToCopyToContainer(): archiver.Archiver {
+  private async createArchiveToCopyToContainer(): Promise<archiver.Archiver> {
     const tar = archiver("tar");
+    const filesToCopyWithStats = await Promise.all(
+      this.filesToCopy.map(async (fileToCopy) => ({
+        ...fileToCopy,
+        stats: await fs.stat(fileToCopy.source),
+      }))
+    );
 
-    for (const { source, target, mode } of this.filesToCopy) {
-      tar.file(source, { name: target, mode });
+    for (const { source, target, mode, stats } of filesToCopyWithStats) {
+      tar.file(source, { name: target, mode, stats });
     }
     for (const { source, target, mode } of this.directoriesToCopy) {
       tar.directory(source, target, { mode });

packages/testcontainers/src/generic-container/started-generic-container.ts

@@ -1,6 +1,7 @@
 import archiver from "archiver";
 import AsyncLock from "async-lock";
 import Dockerode, { ContainerInspectInfo } from "dockerode";
+import { promises as fs } from "fs";
 import { Readable } from "stream";
 import { containerLog, log } from "../common";
 import { ContainerRuntimeClient, getContainerRuntimeClient } from "../container-runtime";
@@ -183,7 +184,13 @@ export class StartedGenericContainer implements StartedTestContainer {
     log.debug(`Copying files to container...`, { containerId: this.container.id });
     const client = await getContainerRuntimeClient();
     const tar = archiver("tar");
-    filesToCopy.forEach(({ source, target }) => tar.file(source, { name: target }));
+    const filesToCopyWithStats = await Promise.all(
+      filesToCopy.map(async (fileToCopy) => ({
+        ...fileToCopy,
+        stats: await fs.stat(fileToCopy.source),
+      }))
+    );
+    filesToCopyWithStats.forEach(({ source, target, mode, stats }) => tar.file(source, { name: target, mode, stats }));
     tar.finalize();
     await client.container.putArchive(this.container, tar, "/");
     log.debug(`Copied files to container`, { containerId: this.container.id });

packages/testcontainers/src/utils/test-helper.ts

@@ -2,7 +2,7 @@ import { GetEventsOptions, ImageInspectInfo } from "dockerode";
 import { createServer, Server } from "http";
 import { createSocket } from "node:dgram";
 import fs from "node:fs";
-import { EOL } from "node:os";
+import { EOL, tmpdir } from "node:os";
 import path from "node:path";
 import { Readable } from "stream";
 import { Agent, request } from "undici";
@@ -198,3 +198,21 @@ export async function createTestServer(port: number): Promise<Server> {
   await new Promise<void>((resolve) => server.listen(port, resolve));
   return server;
 }
+
+export const createTempSymlinkedFile = async (
+  content: string
+): Promise<{ source: string; symlink: string } & AsyncDisposable> => {
+  const directory = await fs.promises.mkdtemp(path.join(tmpdir(), "testcontainers-"));
+  const source = path.join(directory, "source.txt");
+  const symlink = path.join(directory, "symlink.txt");
+  await fs.promises.writeFile(source, content);
+  await fs.promises.symlink(source, symlink);
+
+  return {
+    source,
+    symlink,
+    [Symbol.asyncDispose]: async () => {
+      await fs.promises.rm(directory, { recursive: true, force: true });
+    },
+  };
+};