Improve error message from image building

Translate IOException to DockerException for a more meaningful error
message when the Docker daemon is not available.

Fixes gh-20151

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/HttpClientHttp.java

@@ -19,6 +19,8 @@ package org.springframework.boot.buildpack.platform.docker;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.io.PrintWriter;
+import java.io.StringWriter;
 import java.net.URI;
 
 import org.apache.http.HttpEntity;
@@ -36,7 +38,6 @@ import org.apache.http.entity.AbstractHttpEntity;
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.http.impl.client.HttpClients;
-import org.apache.http.util.EntityUtils;
 
 import org.springframework.boot.buildpack.platform.io.Content;
 import org.springframework.boot.buildpack.platform.io.IOConsumer;
@@ -46,6 +47,7 @@ import org.springframework.boot.buildpack.platform.json.SharedObjectMapper;
  * {@link Http} implementation backed by a {@link HttpClient}.
  *
  * @author Phillip Webb
+ * @author Mike Smithson
  */
 class HttpClientHttp implements Http {
 
@@ -66,10 +68,9 @@ class HttpClientHttp implements Http {
 	 * Perform a HTTP GET operation.
 	 * @param uri the destination URI
 	 * @return the operation response
-	 * @throws IOException on IO error
 	 */
 	@Override
-	public Response get(URI uri) throws IOException {
+	public Response get(URI uri) {
 		return execute(new HttpGet(uri));
 	}
 
@@ -77,10 +78,9 @@ class HttpClientHttp implements Http {
 	 * Perform a HTTP POST operation.
 	 * @param uri the destination URI
 	 * @return the operation response
-	 * @throws IOException on IO error
 	 */
 	@Override
-	public Response post(URI uri) throws IOException {
+	public Response post(URI uri) {
 		return execute(new HttpPost(uri));
 	}
 
@@ -90,11 +90,10 @@ class HttpClientHttp implements Http {
 	 * @param contentType the content type to write
 	 * @param writer a content writer
 	 * @return the operation response
-	 * @throws IOException on IO error
 	 */
 
 	@Override
-	public Response post(URI uri, String contentType, IOConsumer<OutputStream> writer) throws IOException {
+	public Response post(URI uri, String contentType, IOConsumer<OutputStream> writer) {
 		return execute(new HttpPost(uri), contentType, writer);
 	}
 
@@ -104,11 +103,10 @@ class HttpClientHttp implements Http {
 	 * @param contentType the content type to write
 	 * @param writer a content writer
 	 * @return the operation response
-	 * @throws IOException on IO error
 	 */
 
 	@Override
-	public Response put(URI uri, String contentType, IOConsumer<OutputStream> writer) throws IOException {
+	public Response put(URI uri, String contentType, IOConsumer<OutputStream> writer) {
 		return execute(new HttpPut(uri), contentType, writer);
 	}
 
@@ -116,39 +114,44 @@ class HttpClientHttp implements Http {
 	 * Perform a HTTP DELETE operation.
 	 * @param uri the destination URI
 	 * @return the operation response
-	 * @throws IOException on IO error
 	 */
 
 	@Override
-	public Response delete(URI uri) throws IOException {
+	public Response delete(URI uri) {
 		return execute(new HttpDelete(uri));
 	}
 
 	private Response execute(HttpEntityEnclosingRequestBase request, String contentType,
-			IOConsumer<OutputStream> writer) throws IOException {
+			IOConsumer<OutputStream> writer) {
 		request.setHeader(HttpHeaders.CONTENT_TYPE, contentType);
 		request.setEntity(new WritableHttpEntity(writer));
 		return execute(request);
 	}
 
-	private Response execute(HttpUriRequest request) throws IOException {
-		CloseableHttpResponse response = this.client.execute(request);
-		StatusLine statusLine = response.getStatusLine();
-		int statusCode = statusLine.getStatusCode();
-		HttpEntity entity = response.getEntity();
-		if (statusCode >= 200 && statusCode < 300) {
-			return new HttpClientResponse(response);
-		}
-		Errors errors = null;
-		if (statusCode >= 400 && statusCode < 500) {
-			try {
-				errors = SharedObjectMapper.get().readValue(entity.getContent(), Errors.class);
+	private Response execute(HttpUriRequest request) {
+		CloseableHttpResponse response;
+		try {
+			response = this.client.execute(request);
+			StatusLine statusLine = response.getStatusLine();
+			int statusCode = statusLine.getStatusCode();
+			HttpEntity entity = response.getEntity();
+
+			if (statusCode >= 400 && statusCode < 500) {
+				Errors errors = SharedObjectMapper.get().readValue(entity.getContent(), Errors.class);
+				throw new DockerException(request.getURI(), statusCode, statusLine.getReasonPhrase(), errors);
 			}
-			catch (Exception ex) {
+			if (statusCode == 500) {
+				throw new DockerException(request.getURI(), statusCode, statusLine.getReasonPhrase(), null);
 			}
 		}
-		EntityUtils.consume(entity);
-		throw new DockerException(request.getURI(), statusCode, statusLine.getReasonPhrase(), errors);
+		catch (IOException ioe) {
+			StringWriter stringWriter = new StringWriter();
+			PrintWriter printWriter = new PrintWriter(stringWriter);
+			ioe.printStackTrace(printWriter);
+			throw new DockerException(request.getURI(), 500, stringWriter.toString(), null);
+		}
+
+		return new HttpClientResponse(response);
 	}
 
 	/**
@@ -175,7 +178,7 @@ class HttpClientHttp implements Http {
 		}
 
 		@Override
-		public InputStream getContent() throws IOException, UnsupportedOperationException {
+		public InputStream getContent() throws UnsupportedOperationException {
 			throw new UnsupportedOperationException();
 		}
 

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/docker/HttpClientHttpTests.java

@@ -26,7 +26,6 @@ import org.apache.http.HttpEntity;
 import org.apache.http.HttpEntityEnclosingRequest;
 import org.apache.http.HttpHeaders;
 import org.apache.http.StatusLine;
-import org.apache.http.client.ClientProtocolException;
 import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpDelete;
 import org.apache.http.client.methods.HttpGet;
@@ -54,6 +53,7 @@ import static org.mockito.Mockito.verify;
  * Tests for {@link HttpClientHttp}.
  *
  * @author Phillip Webb
+ * @author Mike Smithson
  */
 class HttpClientHttpTests {
 
@@ -132,7 +132,7 @@ class HttpClientHttpTests {
 		assertThat(entity.isRepeatable()).isFalse();
 		assertThat(entity.getContentLength()).isEqualTo(-1);
 		assertThat(entity.isStreaming()).isTrue();
-		assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(() -> entity.getContent());
+		assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(entity::getContent);
 		assertThat(writeToString(entity)).isEqualTo("test");
 		assertThat(response.getContent()).isSameAs(this.content);
 	}
@@ -152,7 +152,7 @@ class HttpClientHttpTests {
 		assertThat(entity.isRepeatable()).isFalse();
 		assertThat(entity.getContentLength()).isEqualTo(-1);
 		assertThat(entity.isStreaming()).isTrue();
-		assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(() -> entity.getContent());
+		assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(entity::getContent);
 		assertThat(writeToString(entity)).isEqualTo("test");
 		assertThat(response.getContent()).isSameAs(this.content);
 	}
@@ -171,7 +171,7 @@ class HttpClientHttpTests {
 	}
 
 	@Test
-	void executeWhenResposeIsIn400RangeShouldThrowDockerException() throws ClientProtocolException, IOException {
+	void executeWhenResposeIsIn400RangeShouldThrowDockerException() throws IOException {
 		given(this.entity.getContent()).willReturn(getClass().getResourceAsStream("errors.json"));
 		given(this.statusLine.getStatusCode()).willReturn(404);
 		assertThatExceptionOfType(DockerException.class).isThrownBy(() -> this.http.get(this.uri))
@@ -179,12 +179,20 @@ class HttpClientHttpTests {
 	}
 
 	@Test
-	void executeWhenResposeIsIn500RangeShouldThrowDockerException() throws ClientProtocolException, IOException {
+	void executeWhenResposeIsIn500RangeShouldThrowDockerException() {
 		given(this.statusLine.getStatusCode()).willReturn(500);
 		assertThatExceptionOfType(DockerException.class).isThrownBy(() -> this.http.get(this.uri))
 				.satisfies((ex) -> assertThat(ex.getErrors()).isNull());
 	}
 
+	@Test
+	void executeWhenClientExecutesRequestThrowsIOExceptionRethrowsAsDockerException() throws IOException {
+		given(this.client.execute(any())).willThrow(IOException.class);
+		assertThatExceptionOfType(DockerException.class).isThrownBy(() -> this.http.get(this.uri))
+				.satisfies((ex) -> assertThat(ex.getErrors()).isNull()).satisfies(DockerException::getStatusCode)
+				.withMessageContaining("500").satisfies((ex) -> assertThat(ex.getReasonPhrase())).isNotNull();
+	}
+
 	private String writeToString(HttpEntity entity) throws IOException {
 		ByteArrayOutputStream out = new ByteArrayOutputStream();
 		entity.writeTo(out);