/*
* Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Git Development Community nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.spearce.jgit.transport;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.Map;
import java.util.Properties;
import java.util.TreeMap;
import org.spearce.jgit.errors.NotSupportedException;
import org.spearce.jgit.errors.TransportException;
import org.spearce.jgit.lib.Constants;
import org.spearce.jgit.lib.ObjectId;
import org.spearce.jgit.lib.ProgressMonitor;
import org.spearce.jgit.lib.Ref;
import org.spearce.jgit.lib.Repository;
import org.spearce.jgit.lib.Ref.Storage;
import org.spearce.jgit.util.FS;
/**
* Transport over the non-Git aware Amazon S3 protocol.
* <p>
* This transport communicates with the Amazon S3 servers (a non-free commercial
* hosting service that users must subscribe to). Some users may find transport
* to and from S3 to be a useful backup service.
* <p>
* The transport does not require any specialized Git support on the remote
* (server side) repository, as Amazon does not provide any such support.
* Repository files are retrieved directly through the S3 API, which uses
* extended HTTP/1.1 semantics. This make it possible to read or write Git data
* from a remote repository that is stored on S3.
* <p>
* Unlike the HTTP variant (see {@link TransportHttp}) we rely upon being able
* to list objects in a bucket, as the S3 API supports this function. By listing
* the bucket contents we can avoid relying on <code>objects/info/packs</code>
* or <code>info/refs</code> in the remote repository.
* <p>
* Concurrent pushing over this transport is not supported. Multiple concurrent
* push operations may cause confusion in the repository state.
*
* @see WalkFetchConnection
* @see WalkPushConnection
*/
public class TransportAmazonS3 extends HttpTransport implements WalkTransport {
static final String S3_SCHEME = "amazon-s3";
static boolean canHandle(final URIish uri) {
if (!uri.isRemote())
return false;
return S3_SCHEME.equals(uri.getScheme());
}
/** User information necessary to connect to S3. */
private final AmazonS3 s3;
/** Bucket the remote repository is stored in. */
private final String bucket;
/**
* Key prefix which all objects related to the repository start with.
* <p>
* The prefix does not start with "/".
* <p>
* The prefix does not end with "/". The trailing slash is stripped during
* the constructor if a trailing slash was supplied in the URIish.
* <p>
* All files within the remote repository start with
* <code>keyPrefix + "/"</code>.
*/
private final String keyPrefix;
TransportAmazonS3(final Repository local, final URIish uri)
throws NotSupportedException {
super(local, uri);
Properties props = null;
File propsFile = new File(local.getDirectory(), uri.getUser());
if (!propsFile.isFile())
propsFile = new File(FS.userHome(), uri.getUser());
if (propsFile.isFile()) {
try {
props = AmazonS3.properties(propsFile);
} catch (IOException e) {
throw new NotSupportedException("cannot read " + propsFile, e);
}
} else {
props = new Properties();
props.setProperty("accesskey", uri.getUser());
props.setProperty("secretkey", uri.getPass());
}
s3 = new AmazonS3(props);
bucket = uri.getHost();
String p = uri.getPath();
if (p.startsWith("/"))
p = p.substring(1);
if (p.endsWith("/"))
p = p.substring(0, p.length() - 1);
keyPrefix = p;
}
@Override
public FetchConnection openFetch() throws TransportException {
final DatabaseS3 c = new DatabaseS3(bucket, keyPrefix + "/objects");
final WalkFetchConnection r = new WalkFetchConnection(this, c);
r.available(c.readAdvertisedRefs());
return r;
}
@Override
public PushConnection openPush() throws TransportException {
final DatabaseS3 c = new DatabaseS3(bucket, keyPrefix + "/objects");
final WalkPushConnection r = new WalkPushConnection(this, c);
r.available(c.readAdvertisedRefs());
return r;
}
@Override
public void close() {
// No explicit connections are maintained.
}
class DatabaseS3 extends WalkRemoteObjectDatabase {
private final String bucketName;
private final String objectsKey;
DatabaseS3(final String b, final String o) {
bucketName = b;
objectsKey = o;
}
private String resolveKey(String subpath) {
if (subpath.endsWith("/"))
subpath = subpath.substring(0, subpath.length() - 1);
String k = objectsKey;
while (subpath.startsWith(ROOT_DIR)) {
k = k.substring(0, k.lastIndexOf('/'));
subpath = subpath.substring(3);
}
return k + "/" + subpath;
}
@Override
URIish getURI() {
URIish u = new URIish();
u = u.setScheme(S3_SCHEME);
u = u.setHost(bucketName);
u = u.setPath("/" + objectsKey);
return u;
}
@Override
Collection<WalkRemoteObjectDatabase> getAlternates() throws IOException {
try {
return readAlternates(INFO_ALTERNATES);
} catch (FileNotFoundException err) {
// Fall through.
}
return null;
}
@Override
WalkRemoteObjectDatabase openAlternate(final String location)
throws IOException {
return new DatabaseS3(bucketName, resolveKey(location));
}
@Override
Collection<String> getPackNames() throws IOException {
final HashSet<String> have = new HashSet<String>();
have.addAll(s3.list(bucket, resolveKey("pack")));
final Collection<String> packs = new ArrayList<String>();
for (final String n : have) {
if (!n.startsWith("pack-") || !n.endsWith(".pack"))
continue;
final String in = n.substring(0, n.length() - 5) + ".idx";
if (have.contains(in))
packs.add(n);
}
return packs;
}
@Override
FileStream open(final String path) throws IOException {
final URLConnection c = s3.get(bucket, resolveKey(path));
final InputStream raw = c.getInputStream();
final InputStream in = s3.decrypt(c);
final int len = c.getContentLength();
return new FileStream(in, raw == in ? len : -1);
}
@Override
void deleteFile(final String path) throws IOException {
s3.delete(bucket, resolveKey(path));
}
@Override
OutputStream writeFile(final String path,
final ProgressMonitor monitor, final String monitorTask)
throws IOException {
return s3.beginPut(bucket, resolveKey(path), monitor, monitorTask);
}
@Override
void writeFile(final String path, final byte[] data) throws IOException {
s3.put(bucket, resolveKey(path), data);
}
Map<String, Ref> readAdvertisedRefs() throws TransportException {
final TreeMap<String, Ref> avail = new TreeMap<String, Ref>();
readPackedRefs(avail);
readLooseRefs(avail);
readRef(avail, Constants.HEAD);
return avail;
}
private void readLooseRefs(final TreeMap<String, Ref> avail)
throws TransportException {
try {
for (final String n : s3.list(bucket, resolveKey(ROOT_DIR
+ "refs")))
readRef(avail, "refs/" + n);
} catch (IOException e) {
throw new TransportException(getURI(), "cannot list refs", e);
}
}
private Ref readRef(final TreeMap<String, Ref> avail, final String rn)
throws TransportException {
final String s;
String ref = ROOT_DIR + rn;
try {
final BufferedReader br = openReader(ref);
try {
s = br.readLine();
} finally {
br.close();
}
} catch (FileNotFoundException noRef) {
return null;
} catch (IOException err) {
throw new TransportException(getURI(), "read " + ref, err);
}
if (s == null)
throw new TransportException(getURI(), "Empty ref: " + rn);
if (s.startsWith("ref: ")) {
final String target = s.substring("ref: ".length());
Ref r = avail.get(target);
if (r == null)
r = readRef(avail, target);
if (r == null)
return null;
r = new Ref(r.getStorage(), rn, r.getObjectId(), r
.getPeeledObjectId(), r.isPeeled());
avail.put(r.getName(), r);
return r;
}
if (ObjectId.isId(s)) {
final Ref r = new Ref(loose(avail.get(rn)), rn, ObjectId
.fromString(s));
avail.put(r.getName(), r);
return r;
}
throw new TransportException(getURI(), "Bad ref: " + rn + ": " + s);
}
private Storage loose(final Ref r) {
if (r != null && r.getStorage() == Storage.PACKED)
return Storage.LOOSE_PACKED;
return Storage.LOOSE;
}
@Override
void close() {
// We do not maintain persistent connections.
}
}
}