Belle II Software  release-05-01-25
ZMQRawInput Class Reference

Input connection allowing to speak with non-zmq sockets via a ZMQ_STREAM socket. More...

#include <ZMQRawConnection.h>

Inheritance diagram for ZMQRawInput:
Collaboration diagram for ZMQRawInput:

Public Types

using ReactorFunction = std::function< void(void)>
 Typedef of a function which will be called if a connection has a message.
 

Public Member Functions

 ZMQRawInput (const std::string &inputAddress, unsigned int maximalBufferSize, bool receiveEventMessages, const std::shared_ptr< ZMQParent > &parent)
 Create a new raw input connection. The bind or connect behavior is chosen according to the given address.
 
std::vector< zmq::message_t > handleIncomingData ()
 Block until a TCP packet can be received from the socket. More...
 
void clear ()
 Reset the internal buffer and counter.
 
std::vector< zmq::socket_t * > getSockets () const final
 The socket used for polling is just the stored socket.
 
virtual bool isReady () const
 Return true of this connection is able to send messages right now. Can be overloaded in derived classes.
 
virtual std::string getMonitoringJSON () const
 Convert the stored monitoring values to a JSON string ready for sending out via a message.
 
template<class AClass >
void log (const std::string &key, const AClass &value)
 Store a value under a certain key. Different types of values can be stored, namely long, double or string. Mixtures are not allowed for a given key.
 
void increment (const std::string &key)
 Increment the value with the given key (only numerical values). If not present, set to 1.
 
void decrement (const std::string &key)
 Decrement the value with the given key (only numerical values). If not present, set to -1.
 
template<size_t MAX_SIZE = 100>
void average (const std::string &key, double value)
 Instead of storeing the double value directly under the given key, store the average of the last MAX_SIZE values.
 
template<size_t AVERAGE_SIZE = 2000>
void timeit (const std::string &key)
 Measure the rate of calls with the same key every AVERAGE_SIZE calls (and also display the last time AVERAGE_SIZE was reached under <key>_last_measurement)
 
void logTime (const std::string &key)
 Store the current time as a string under the given key.
 

Static Public Member Functions

static bool poll (const std::map< const ZMQConnection *, ReactorFunction > &connectionList, int timeout)
 Poll on the given connections and call the attached function if a messages comes in. More...
 
static bool hasMessage (const ZMQConnection *connection)
 Check if the given connection as an incoming message (right now, no waiting).
 

Protected Attributes

std::shared_ptr< ZMQParentm_parent
 The shared ZMQParent instance.
 
std::unique_ptr< zmq::socket_t > m_socket
 The memory of the socket. Needs to be initialized in a derived class.
 

Private Attributes

unsigned int m_maximalBufferSize
 Parameter for the maximal buffer size. If this size is reached, a FATAL will be issued.
 
std::vector< char > m_buffer
 Internal storage for the buffer.
 
size_t m_writeAddress = 0
 Where in the buffer are we currently writing to.
 
unsigned int m_currentSize = 0
 How large should the full message be? The information is from the first int of the message.
 
bool m_receiveEventMessages
 Parameter to receive event messages (see above)
 
std::string m_inputIdentity = ""
 Internal storage of the connected socket to check if we get messages from multiple ones.
 
std::map< std::string, std::variant< long, double, std::string > > m_monitoring
 Internal storage of all stored values.
 
std::unordered_map< std::string, std::tuple< std::vector< double >, size_t > > m_averages
 Internal storage of the previous values when calculating averages.
 
std::unordered_map< std::string, std::tuple< unsigned long, std::chrono::system_clock::time_point > > m_timeCounters
 Internal storage how often the timeit function for a given key was called and when it has last reached MAX_SIZE.
 

Detailed Description

Input connection allowing to speak with non-zmq sockets via a ZMQ_STREAM socket.

Can only speak with a single socket.

On receiving a TC packet, it is stored in an internal buffer. Only if the message is complete it is returned wrapped up as a zmq:message_t.

Two message formats are understood:

  • if receiveEventMessages is set to false, the first int of the message must be the size L of the message, in units of sizeof(int) = words. (so full message size in bytes = L * sizeof(int)) Please note that this size also includes this first int, so the real data message has a size in bytes of L * sizeof(int) - sizeof(int)
  • if it is true, the first int of the message must be the ntohl-converted size of the message in bytes without this first size int.

The two message formats are chosen to be compatible with the HLT implementation.

Definition at line 51 of file ZMQRawConnection.h.

Member Function Documentation

◆ handleIncomingData()

std::vector< zmq::message_t > handleIncomingData ( )

Block until a TCP packet can be received from the socket.

Returns only full messages as zmq:message_t. Please note that this can be

  • 0 messages if there has not been a full message so far
  • 1 message if there was
  • more than 1 if the message size is smaller than the TCP package size (~8kB)

Definition at line 48 of file ZMQRawConnection.cc.

49 {
50  std::vector<zmq::message_t> receivedMessages;
51 
52  // We will always get one or two parts. The first one is the identity..
53  zmq::message_t identity;
54  m_socket->recv(&identity);
55  std::string identityString(identity.data<char>(), identity.size());
56  B2ASSERT("The message is incomplete!", m_socket->getsockopt<int>(ZMQ_RCVMORE) == 1);
57  B2ASSERT("The app can only handle a single connection!",
58  m_inputIdentity == identityString or m_inputIdentity.empty());
59 
60  // ... and the second one is the message itself.
61  const size_t remainingSpace = m_maximalBufferSize - m_writeAddress;
62  const size_t receivedBytes = m_socket->recv(&m_buffer[m_writeAddress], remainingSpace);
63  B2ASSERT("The message is longer than expected! Increase the buffer size.", m_socket->getsockopt<int>(ZMQ_RCVMORE) == 0);
64  if (receivedBytes == 0) {
65  // Empty message means the client connected or disconnected
66  if (m_inputIdentity.empty()) {
67  m_inputIdentity = identityString;
68  log("socket_state", "connected");
69  increment("socket_connects");
70  } else {
71  m_inputIdentity = "";
72  log("socket_state", "disconnected");
73  increment("socket_disconnects");
74  }
75  return receivedMessages;
76  }
77  // We can maximal write `remainingSpace` into the buffer. If the message was longer, ZMQ will just cut it.
78  // This means we are loosing data and the buffer size should be increased.
79  if (receivedBytes > remainingSpace) {
80  B2FATAL("The size of the buffer is too small! " << receivedBytes << " > " << remainingSpace);
81  }
82  average("average_received_byte_packages", receivedBytes);
83 
84  // `m_writeAddress` always points to the index on where we will write next.
85  // As we have written `receivedBytes` we need to advance
86  m_writeAddress += receivedBytes;
87 
88  log("write_address", static_cast<long>(m_writeAddress));
89 
90  // If the current buffer is smaller than an int, we can not get the size
91  while (m_writeAddress >= sizeof(int)) {
92  if (m_currentSize == 0) {
93  // we do not know the size of the data package already, so lets get it from the buffer.
94  // It is always in the first sizeof(int) of the data
95  memcpy(&m_currentSize, &m_buffer[0], sizeof(int));
96 
97  // Here the two different message formats differ
100  }
101  B2ASSERT("Strange size in the data!", m_currentSize > 0);
103  m_currentSize += sizeof(int);
104  } else {
105  m_currentSize *= sizeof(int);
106  }
107 
108  log("current_size", static_cast<long>(m_currentSize));
109  }
110  if (m_writeAddress >= m_currentSize) {
111  // Now we know the size already, and we have enough data received so we have actually the full
112  // data. We can build the total message.
113  average("data_size", m_currentSize);
114  increment("received_events");
115  timeit("event_rate");
116 
117  // Again, here the two different message formats differ. One includes the first int with the length...
118  unsigned int startAddress = 0;
120  // .. and the other does not
121  startAddress = sizeof(int);
122  }
123  zmq::message_t dataMessage(&m_buffer[startAddress], static_cast<size_t>(m_currentSize - startAddress));
124 
127  m_currentSize = 0;
128 
129  log("write_address", static_cast<long>(m_writeAddress));
130  log("current_size", static_cast<long>(m_currentSize));
131 
132  receivedMessages.push_back(std::move(dataMessage));
133  } else {
134  // We did not receive a full message up to now
135  break;
136  }
137  }
138 
139  average("average_number_of_events_per_package", receivedMessages.size());
140  return receivedMessages;
141 }

◆ poll()

bool poll ( const std::map< const ZMQConnection *, ReactorFunction > &  connectionList,
int  timeout 
)
staticinherited

Poll on the given connections and call the attached function if a messages comes in.

If after timeout milliseconds still no message is received, return anyways. If timeout is 0, do not wait. If timeout is -1, wait infinitely.

Returns true if a message was received on any socket, false otherwise. Attention: in case of an interrupted system call (e.g. because a signal was received) the function might return anyways with a negative result even before the timeout!

Definition at line 29 of file ZMQConnection.cc.


The documentation for this class was generated from the following files:
Belle2::ZMQLogger::timeit
void timeit(const std::string &key)
Measure the rate of calls with the same key every AVERAGE_SIZE calls (and also display the last time ...
Definition: ZMQLogger.h:127
Belle2::ZMQRawInput::m_receiveEventMessages
bool m_receiveEventMessages
Parameter to receive event messages (see above)
Definition: ZMQRawConnection.h:79
Belle2::ZMQLogger::log
void log(const std::string &key, const AClass &value)
Store a value under a certain key. Different types of values can be stored, namely long,...
Definition: ZMQLogger.h:106
Belle2::ZMQRawInput::m_maximalBufferSize
unsigned int m_maximalBufferSize
Parameter for the maximal buffer size. If this size is reached, a FATAL will be issued.
Definition: ZMQRawConnection.h:71
Belle2::ZMQLogger::increment
void increment(const std::string &key)
Increment the value with the given key (only numerical values). If not present, set to 1.
Definition: ZMQLogger.cc:34
Belle2::ZMQRawInput::m_inputIdentity
std::string m_inputIdentity
Internal storage of the connected socket to check if we get messages from multiple ones.
Definition: ZMQRawConnection.h:81
Belle2::ZMQRawInput::m_currentSize
unsigned int m_currentSize
How large should the full message be? The information is from the first int of the message.
Definition: ZMQRawConnection.h:77
Belle2::ZMQLogger::average
void average(const std::string &key, double value)
Instead of storeing the double value directly under the given key, store the average of the last MAX_...
Definition: ZMQLogger.h:112
Belle2::ZMQRawInput::m_buffer
std::vector< char > m_buffer
Internal storage for the buffer.
Definition: ZMQRawConnection.h:73
Belle2::ZMQConnectionOverSocket::m_socket
std::unique_ptr< zmq::socket_t > m_socket
The memory of the socket. Needs to be initialized in a derived class.
Definition: ZMQConnection.h:84
Belle2::ZMQRawInput::m_writeAddress
size_t m_writeAddress
Where in the buffer are we currently writing to.
Definition: ZMQRawConnection.h:75