Improve PortCheck logging for distroless images (#954)

Author: digital88

packages/testcontainers/fixtures/docker/docker-no-shell/Dockerfile

@@ -0,0 +1,11 @@
+FROM node AS build
+WORKDIR /app
+RUN npm init -y \
+    && npm install [email protected]
+COPY index.js .
+
+FROM gcr.io/distroless/nodejs20-debian12 AS app
+EXPOSE 8080
+COPY --from=build /app /app
+WORKDIR /app
+CMD ["index.js"]

packages/testcontainers/fixtures/docker/docker-no-shell/index.js

@@ -0,0 +1,14 @@
+const http = require("http");
+const express = require("express");
+
+const app = express();
+
+app.get("/hello-world", (req, res) => {
+  res.status(200).send("hello-world");
+});
+
+const PORT = 8080;
+
+http
+  .createServer(app)
+  .listen(PORT, () => console.log(`Listening on port ${PORT}`));

packages/testcontainers/src/wait-strategies/utils/port-check.test.ts

@@ -140,5 +140,43 @@ describe("PortCheck", () => {
         ],
       ]);
     });
+
+    it("should error log the distroless image once, regardless of logs enabled or not", async () => {
+      // Make sure logging is disabled explicitly here
+      mockLogger.enabled.mockImplementation(() => false);
+
+      mockContainerExec
+        .mockReturnValueOnce(Promise.resolve({ output: "ERROR 1", exitCode: 126 }))
+        .mockReturnValueOnce(Promise.resolve({ output: "ERROR 2", exitCode: 126 }))
+        .mockReturnValueOnce(Promise.resolve({ output: "ERROR 2", exitCode: 126 }))
+        .mockReturnValueOnce(Promise.resolve({ output: "ERROR 1", exitCode: 126 }))
+        .mockReturnValueOnce(Promise.resolve({ output: "ERROR 2", exitCode: 126 }))
+        .mockReturnValueOnce(Promise.resolve({ output: "ERROR 2", exitCode: 126 }));
+
+      await portCheck.isBound(8080);
+      await portCheck.isBound(8080);
+
+      expect(mockLogger.error.mock.calls).toEqual([
+        [
+          "The HostPortWaitStrategy will not work on a distroless image, use an alternate wait strategy",
+          { containerId: "containerId" },
+        ],
+      ]);
+    });
+
+    it.for([126, 127])("should error log the distroless image when exit code is %i", async (code) => {
+      mockContainerExec.mockReturnValueOnce(Promise.resolve({ output: "ERROR 1", exitCode: code }));
+      mockContainerExec.mockReturnValueOnce(Promise.resolve({ output: "ERROR 2", exitCode: code }));
+      mockContainerExec.mockReturnValueOnce(Promise.resolve({ output: "ERROR 3", exitCode: code }));
+
+      await portCheck.isBound(8080);
+
+      expect(mockLogger.error.mock.calls).toEqual([
+        [
+          "The HostPortWaitStrategy will not work on a distroless image, use an alternate wait strategy",
+          { containerId: "containerId" },
+        ],
+      ]);
+    });
   });
 });

packages/testcontainers/src/wait-strategies/utils/port-check.ts

@@ -33,7 +33,7 @@ export class HostPortCheck implements PortCheck {
 
 export class InternalPortCheck implements PortCheck {
   private isDistroless = false;
-  private commandOutputs = new Set<string>();
+  private readonly commandOutputs = new Set<string>();
 
   constructor(
     private readonly client: ContainerRuntimeClient,
@@ -53,28 +53,29 @@ export class InternalPortCheck implements PortCheck {
     );
     const isBound = commandResults.some((result) => result.exitCode === 0);
 
+    // https://www.gnu.org/software/bash/manual/html_node/Exit-Status.html
+    // If a command is not found, the child process created to execute it returns a status of 127.
+    // If a command is found but is not executable, the return status is 126.
+    const shellExists = commandResults.some((result) => result.exitCode !== 126 && result.exitCode !== 127);
+    if (!isBound && !shellExists && !this.isDistroless) {
+      this.isDistroless = true;
+      log.error(`The HostPortWaitStrategy will not work on a distroless image, use an alternate wait strategy`, {
+        containerId: this.container.id,
+      });
+    }
+
     if (!isBound && log.enabled()) {
-      const shellExists = commandResults.some((result) => result.exitCode !== 126);
-      if (!shellExists) {
-        if (!this.isDistroless) {
-          this.isDistroless = true;
-          log.error(`The HostPortWaitStrategy will not work on a distroless image, use an alternate wait strategy`, {
-            containerId: this.container.id,
-          });
-        }
-      } else {
-        commandResults
-          .map((result) => ({ ...result, output: result.output.trim() }))
-          .filter((result) => result.exitCode !== 126 && result.output.length > 0)
-          .forEach((result) => {
-            if (!this.commandOutputs.has(this.commandOutputsKey(result.output))) {
-              log.trace(`Port check result exit code ${result.exitCode}: ${result.output}`, {
-                containerId: this.container.id,
-              });
-              this.commandOutputs.add(this.commandOutputsKey(result.output));
-            }
-          });
-      }
+      commandResults
+        .map((result) => ({ ...result, output: result.output.trim() }))
+        .filter((result) => result.exitCode !== 126 && result.output.length > 0)
+        .forEach((result) => {
+          if (!this.commandOutputs.has(this.commandOutputsKey(result.output))) {
+            log.trace(`Port check result exit code ${result.exitCode}: ${result.output}`, {
+              containerId: this.container.id,
+            });
+            this.commandOutputs.add(this.commandOutputsKey(result.output));
+          }
+        });
     }
 
     return isBound;