multithreaded downloads and non docker registries

Runs each layer download on a different thread.
Allows using registries other than registry.docker.io

1 files changed, 77 insertions, 0 deletions

diff --git a/src/main/java/io/github/jshipit/BlobDownloader.java b/src/main/java/io/github/jshipit/BlobDownloader.java
new file mode 100644
index 0000000..5fa3959
--- /dev/null
+++ b/src/main/java/io/github/jshipit/BlobDownloader.java
@@ -0,0 +1,77 @@
+package io.github.jshipit;
+
+import me.tongfei.progressbar.ProgressBar;
+
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.*;
+
+public class BlobDownloader extends Thread {
+
+    private final String url;
+    private final String digest;
+    private final String[][] headers;
+    private final String tmpdir;
+
+    public BlobDownloader(String url, String digest, String[][] headers, String tmpdir) {
+        this.url = url;
+        this.digest = digest;
+        this.headers = headers;
+        this.tmpdir = tmpdir;
+    }
+
+    public void run() throws RuntimeException {
+        URL url_obj = null;
+        try {
+            url_obj = new URI(this.url).toURL();
+            System.out.println(url_obj.toString());
+        } catch(URISyntaxException | MalformedURLException e) {
+            System.out.println("URISyntaxException | MalformedURLException");
+            e.printStackTrace();
+        }
+
+        assert url_obj != null;
+        HttpURLConnection con;
+
+        try {
+            con = (HttpURLConnection) url_obj.openConnection();
+            con.setRequestMethod("GET");
+            for (String[] header : this.headers) {
+                con.setRequestProperty(header[0], header[1]);
+            }
+            con.connect();
+
+            if (con.getResponseCode() != 200) {
+                System.out.println("Error: " + con.getResponseCode());
+                throw new RuntimeException("Failed : HTTP error code : "
+                        + con.getResponseCode());
+            } else {
+                System.out.println("Success: " + con.getResponseCode());
+            }
+        } catch (IOException e) {
+            System.out.println("Failed to connect");
+            e.printStackTrace();
+            return;
+        }
+
+
+        int fileSize = con.getContentLength();
+
+        try (InputStream in = con.getInputStream();
+             OutputStream out = new FileOutputStream(tmpdir + "/" + digest.replace("sha256:", "") + "layer.tar")) {
+            byte[] buffer = new byte[4096];
+            int bytesRead;
+            try (ProgressBar pb = new ProgressBar("Download blob "+digest.replace("sha256:", ""), fileSize)) {
+                while ((bytesRead = in.read(buffer)) != -1) {
+                    out.write(buffer, 0, bytesRead);
+                    pb.stepBy(bytesRead);
+                }
+            }
+        } catch (IOException e) {
+            System.out.println("Failed to download blob "+digest);
+            e.printStackTrace();
+        }
+    }
+}