void LogProcess::updated(const string& path)
{
if (znode + "/replicas" == path) {
regroup();
// Reset a watch on the replicas.
int ret = zk->getChildren(znode + "/replicas", true, NULL);
if (ret != ZOK) {
LOG(FATAL) << "Failed to set a watch on '" << znode << "/replicas"
<< "' in ZooKeeper: " << zk->message(ret);
}
} else {
CHECK(znode + "/coordinators" == path);
elect();
// Reset a watch on the coordinators.
int ret = zk->getChildren(znode + "/coordinators", true, NULL);
if (ret != ZOK) {
LOG(FATAL) << "Failed to set a watch on '" << znode << "/replicas"
<< "' in ZooKeeper: " << zk->message(ret);
}
}
}
Future<bool> ZooKeeperSlavesManagerStorage::remove(const string& hostname, uint16_t port)
{
// TODO(benh): Use ZooKeeperSlavesManagerStorage::parse to clean up code.
int ret;
string result;
Stat stat;
ret = zk->get(znode, true, &result, &stat);
if (ret != ZOK) {
LOG(WARNING) << "Slaves manager storage failed to get '" << znode
<< "' in ZooKeeper! (" << zk->message(ret) << ")";
return false;
}
ostringstream out;
out << hostname << ":" << port;
size_t index = result.find(out.str());
if (index == string::npos) {
LOG(WARNING) << "Slaves manager storage could not remove slave "
<< hostname << ":" << port
<< " because not currently active or inactive";
return false;
} else if (index == 0) {
LOG(WARNING) << "Bad data in '" << znode;
return false;
}
if (result[index - 1] == '=') {
if (result[index + out.str().size()] == '\n') {
result.erase(index, out.str().size());
} else {
result.erase(index, out.str().size() + 1);
}
} else {
result.erase(index - 1, out.str().size() + 1);
}
// Set the data in the znode.
ret = zk->set(znode, result, stat.version);
if (ret != ZOK) {
LOG(WARNING) << "Slaves manager storage could not remove slave "
<< hostname << ":" << port
<< " from '" << znode << "' in ZooKeeper! ("
<< zk->message(ret) << ")";
return false;
}
return true;
}
Future<bool> ZooKeeperSlavesManagerStorage::add(const string& hostname, uint16_t port)
{
// TODO(benh): Use ZooKeeperSlavesManagerStorage::parse to clean up code.
int ret;
string result;
Stat stat;
ret = zk->get(znode, true, &result, &stat);
if (ret != ZOK) {
LOG(WARNING) << "Slaves manager storage failed to get '" << znode
<< "' in ZooKeeper! (" << zk->message(ret) << ")";
return false;
}
ostringstream out;
out << hostname << ":" << port;
if (result.size() == 0) {
out << "active=" << hostname << ":" << port << "\n";
out << "inactive=\n";
result = out.str();
} else {
const string active("active=");
size_t index = result.find(active);
if (index == string::npos) {
LOG(WARNING) << "Slaves manager storage found bad data in '" << znode
<< "', could not find 'active='";
return false;
}
if (result[index + active.size()] != '\n') {
out << ",";
}
result.insert(index + active.size(), out.str());
}
// Set the data in the znode.
ret = zk->set(znode, result, stat.version);
if (ret != ZOK) {
LOG(WARNING) << "Slaves manager storage could not add slave "
<< hostname << ":" << port
<< " to '" << znode << "' in ZooKeeper! ("
<< zk->message(ret) << ")";
return false;
}
return true;
}
Future<bool> ZooKeeperSlavesManagerStorage::updated(const string& path)
{
int ret;
string result;
if (path == znode) {
LOG(INFO) << "Slaves manager storage found updates in ZooKeeper "
<< "... propogating changes";
ret = zk->get(znode, true, &result, NULL);
if (ret != ZOK) {
LOG(WARNING) << "Slaves manager storage failed to get '" << znode
<< "' in ZooKeeper! (" << zk->message(ret) << ")";
return false;
}
// Parse what's in ZooKeeper into active/inactive hostname port pairs.
multihashmap<string, uint16_t> active;
if (parse("active=", result, &active)) {
process::dispatch(slavesManager, &SlavesManager::updateActive, active);
}
multihashmap<string, uint16_t> inactive;
if (parse("inactive=", result, &inactive)) {
process::dispatch(slavesManager, &SlavesManager::updateInactive, inactive);
}
} else {
LOG(WARNING) << "Slaves manager stoage not expecting changes to path '"
<< path << "' in ZooKeeper";
return false;
}
return true;
}
Future<bool> ZooKeeperSlavesManagerStorage::connected()
{
int ret;
static const string delimiter = "/";
// Assume the znode that was created does not end with a "/".
CHECK(znode.at(znode.length() - 1) != '/');
// Create directory path znodes as necessary.
size_t index = znode.find(delimiter, 0);
while (index < string::npos) {
// Get out the prefix to create.
index = znode.find(delimiter, index + 1);
string prefix = znode.substr(0, index);
// Create the node (even if it already exists).
ret = zk->create(prefix, "", ZOO_OPEN_ACL_UNSAFE, 0, NULL);
if (ret != ZOK && ret != ZNODEEXISTS) {
// Okay, consider this a failure (maybe we lost our connection
// to ZooKeeper), increment the failure count, log the issue,
// and perhaps try again when ZooKeeper issues get sorted out.
LOG(WARNING) << "Slaves manager storage failed to create '" << znode
<< "' in ZooKeeper! (" << zk->message(ret) << ")";
return false;
}
}
// Reconcile what's in the znodes versus what we have in memory
// (this also puts watches on these znodes).
return updated(znode);
}
void LogProcess::regroup()
{
vector<string> results;
int ret = zk->getChildren(znode + "/replicas", false, &results);
if (ret != ZOK) {
LOG(FATAL) << "Failed to get children of '" << znode << "/replicas"
<< "' in ZooKeeper: " << zk->message(ret);
}
set<UPID> current;
set<UPID> added;
set<UPID> removed;
foreach (const string& result, results) {
string s;
int ret = zk->get(znode + "/replicas/" + result, false, &s, NULL);
UPID pid = s;
current.insert(pid);
}
void LogProcess::connected()
{
LOG(INFO) << "Log connected to ZooKeeper";
int ret;
string result;
// Assume the znode that was created does not end with a "/".
CHECK(znode.size() == 0 || znode.at(znode.size() - 1) != '/');
// Create directory path znodes as necessary.
size_t index = znode.find("/", 0);
while (index < string::npos) {
// Get out the prefix to create.
index = znode.find("/", index + 1);
string prefix = znode.substr(0, index);
LOG(INFO) << "Log trying to create znode '"
<< prefix << "' in ZooKeeper";
// Create the node (even if it already exists).
ret = zk->create(
prefix,
"",
ZOO_OPEN_ACL_UNSAFE,
// ZOO_CREATOR_ALL_ACL, // needs authentication
0,
&result);
if (ret != ZOK && ret != ZNODEEXISTS) {
LOG(FATAL) << "Failed to create '" << prefix
<< "' in ZooKeeper: " << zk->message(ret);
}
}
// Now create the "replicas" znode.
LOG(INFO) << "Log trying to create znode '" << znode
<< "/replicas" << "' in ZooKeeper";
// Create the node (even if it already exists).
ret = zk->create(znode + "/replicas", "", ZOO_OPEN_ACL_UNSAFE,
// ZOO_CREATOR_ALL_ACL, // needs authentication
0, &result);
if (ret != ZOK && ret != ZNODEEXISTS) {
LOG(FATAL) << "Failed to create '" << znode << "/replicas"
<< "' in ZooKeeper: " << zk->message(ret);
}
// Now create the "coordinators" znode.
LOG(INFO) << "Log trying to create znode '" << znode
<< "/coordinators" << "' in ZooKeeper";
// Create the node (even if it already exists).
ret = zk->create(znode + "/coordinators", "", ZOO_OPEN_ACL_UNSAFE,
// ZOO_CREATOR_ALL_ACL, // needs authentication
0, &result);
if (ret != ZOK && ret != ZNODEEXISTS) {
LOG(FATAL) << "Failed to create '" << znode << "/coordinators"
<< "' in ZooKeeper: " << zk->message(ret);
}
// Okay, create our replica, group, and coordinator.
replica = new ReplicaProcess(file);
spawn(replica);
group = new GroupProcess();
spawn(group);
coordinator = new Coordinator(quorum, replica, group);
// Set a watch on the replicas.
ret = zk->getChildren(znode + "/replicas", true, NULL);
if (ret != ZOK) {
LOG(FATAL) << "Failed to set a watch on '" << znode << "/replicas"
<< "' in ZooKeeper: " << zk->message(ret);
}
// Set a watch on the coordinators.
ret = zk->getChildren(znode + "/coordinators", true, NULL);
if (ret != ZOK) {
LOG(FATAL) << "Failed to set a watch on '" << znode << "/replicas"
<< "' in ZooKeeper: " << zk->message(ret);
}
// Add an ephemeral znode for our replica and coordinator.
ret = zk->create(znode + "/replicas/", replica->self(), ZOO_OPEN_ACL_UNSAFE,
// ZOO_CREATOR_ALL_ACL, // needs authentication
ZOO_SEQUENCE | ZOO_EPHEMERAL, &result);
if (ret != ZOK) {
LOG(FATAL) << "Failed to create an ephmeral node at '" << znode
<< "/replica/" << "' in ZooKeeper: " << zk->message(ret);
}
ret = zk->create(znode + "/coordinators/", "", ZOO_OPEN_ACL_UNSAFE,
// ZOO_CREATOR_ALL_ACL, // needs authentication
ZOO_SEQUENCE | ZOO_EPHEMERAL, &result);
if (ret != ZOK) {
LOG(FATAL) << "Failed to create an ephmeral node at '" << znode
<< "/replica/" << "' in ZooKeeper: " << zk->message(ret);
}
// Save the sequence id but only grab the basename, e.g.,
// "/path/to/znode/000000131" => "000000131".
result = utils::os::basename(result);
try {
id = boost::lexical_cast<uint64_t>(result);
} catch (boost::bad_lexical_cast&) {
LOG(FATAL) << "Failed to convert '" << result << "' into an integer";
}
// Run an election!
elect();
}