Add stub of std-stream-send

This commit is contained in:
2021-07-05 17:59:09 +02:00
parent 13547a5fef
commit 9d56da96f9
9 changed files with 334 additions and 0 deletions
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file(GLOB SOURCES
src/*.cpp)
add_library(std-stream-send-lib STATIC ${SOURCES})
target_include_directories(std-stream-send-lib PUBLIC include/)
target_link_libraries(std-stream-send-lib
core-buffer-lib)
add_executable(std-stream-send src/main.cpp)
set_target_properties(std-stream-send PROPERTIES OUTPUT_NAME std_stream_send)
target_link_libraries(std-stream-send
std-stream-send-lib
zmq
pthread
rt)
enable_testing()
add_subdirectory(test/)
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# sf-stream
sf-stream is the component that receives a live stream of frame data from
sf-buffers over ZMQ and assembles them into images. This images are then
sent again over ZMQ to external components. There is always only 1 sf-stream
per detector.
It currently has 3 output streams:
- **Full data full meta** rate stream (send all images and meta)
- **Reduced data full meta** rate stream (send less images, but
all meta)
- **Pulse_id** stream (send only the current pulse_id)
In addition to receiving and assembling images, sf-stream also calculates
additional meta and constructs the structures needed to send data in
Array 1.0 protocol.
This component does not guarantee that the streams will always contain all
the data - it can happen that frame resynchronization is needed, and in this
case 1 or more frames could potentially be lost. This happens so rarely that in
practice is not a problem.
## Overview
![image_stream_overview](../docs/sf_daq_buffer-overview-stream.jpg)
sf-stream is a single threaded application (without counting the ZMQ IO threads)
that is used for providing live assembled images to anyone willing to listen.
In addition, it also provides a pulse_id stream, which is the most immediate
pulse_id feedback we currently have in case we need to synchronize external
components to the current machine pulse_id.
## ZMQ receiving
Each ZMQ stream is coming from a separate sf-buffer. This means that we have as
many connections as we have modules in a detector.
Messages are multipart (2 parts) and are received in PUB/SUB mode.
There is no need for special synchronization between modules as we expect that
frames will always be in the correct order and all modules will provide the
same frame more or less at the same time. If any of this 2 conditions is not
met, the detector is not working properly and we cannot guaranty that sf-stream
will work correctly.
Nonetheless we provide the capability to synchronize the streams in image
assembly phase - this is needed rarely, but occasionally happens. In this sort
of hiccups we usually loose only a couple of consecutive images.
### Messages format
Each message is composed by 2 parts:
- Serialization of ModuleFrame in the first part.
- Frame data in the second part.
Module frame is defined as:
```c++
#pragma pack(push)
#pragma pack(1)
struct ModuleFrame {
uint64_t pulse_id;
uint64_t frame_index;
uint64_t daq_rec;
uint64_t n_recv_packets;
uint64_t module_id;
};
#pragma pack(pop)
```
The frame data is a 1MB (1024*512 pixels * 2 bytes/pixel) blob of data in
**uint16** representing the detector image.
## Image assembly
We first synchronize the modules. We do this by reading all sockets and
deciding the largest frame pulse_id among them (max_pulse_id). We then calculate
the diff between a specific socket pulse_id and the max_pulse_id.
This difference tells us how many messages we need to discard from a specific socket.
This discarding is the source of possible missing images in the output stream.
It can happen in 3 cases:
- At least one of the detector modules did not sent any packets for the specific
pulse_id.
- All the packets from a specific module for a pulse_id were lost before UDP
receiving them.
- ZMQ HWM was reached (either on the sf-buffer or sf-stream) and the message was
dropped.
All this 3 cases are highly unlikely, so synchronization is mostly needed when
first starting sf-stream. Different sockets connect to sf-buffers at different
times. Apart from the initial synchronization there should be no need to
re-synchronize modules in a healthy running environment.
If an image is missing any ZMQ messages from sf-buffers (not all modules data
arrived), the image will be dropped. We do not do partial reconstruction in
sf-stream. However, it is important to note, that this does not cover the case
where frames are incomplete (missing UDP packets on sf-buffer) - we still
assemble this images as long as at least 1 packet/frame for a specific pulse_id
arrived.
## ZMQ sending
We devide the ZMQ sending to 3 types of stream:
- Data processing stream. This is basically the complete stream from
the detector with all meta and data. It can be described as full data full
meta stream. Only 1 client at the time can be connected to this stream
(PUSH/PULL for load balancing).
- Live viewing stream. This is a reduced data full meta stream. We send
meta for all frames, but data only for subset of them (10Hz, for example).
Any number of clients can connect to the 10Hz stream, because we use PUB/SUB
for this socket.
- Pulse_id stream. This is a stream that sends out only the current pulse_id.
It can be used to synchronize any external system with the current pulse_id
being recorded. Multiple clients can connect to this stream.
In the data processing and live viewing stream we use
[Array 1.0](https://github.com/paulscherrerinstitute/htypes/blob/master/array-1.0.md)
as our protocol to be compatible with currently available external components.
We use following fields in the JSON header:
| Name | Type | Comment |
| --- | --- | --- |
| pulse_id | uint64 |bunchid from detector header|
|frame|uint64|frame_index from detector header|
|is_good_frame|bool|true if all packets for this frame are present|
|daq_rec|uint32|daqrec from detector header|
|pedestal_file|string|Path to pedestal file|
|gain_file|string|Path to gain file|
|number_frames_expected|int|Number of expected frames|
|run_name|string|Name of the run|
|detector_name|string|Name of the detector|
|htype|string|Value: "array-1.0"|
|type|string|Value: "uint16"|
|shape|Array[uint64]|Shape of the image in stream|
### Full data full meta stream
This stream runs at detector frequency and uses PUSH/PULL to distribute data
to max 1 client (this client can have many processes, but it needs to be a
single logical entity, since the images are evenly distributed to all
connected sockets).
![image_full_stream](../docs/sf_daq_buffer-FullStream.jpg)
The goal here is to provide a complete copy of the detector image stream
for purposes of online analysis. Given the large amount of data on this
stream only "pre-approved" applications that can handle the load should be
attached here.
### Reduced data full meta stream
This streams also runs at detector frequency for JSON headers (meta), but
it sends only part of the images in the stream. The rest of the images are
sent as empty buffers (the receiver needs to be aware of this behaviour, as
Array 1.0 alone does not define it).
![image_reduced_stream](../docs/sf_daq_buffer-ReducedStream.jpg)
This is the lightweight version of the image stream. Any number of clients
can connect to this stream (PUB/SUB) but no client can do load
balancing automatically (it would require PUSH/PULL).
This is a "public interface" for anyone who wants to get detector data live,
and can do with only a subset of images.
### Pulse_id stream
This stream runs ar detector frequency in PUB/SUB mode. The only thing it
does is sends out the pulse_id (of the just received image) in uint64_t
format.
![image_pulse_stream](../docs/sf_daq_buffer-PulseStream.jpg)
This is also a "public interface" for anyone who wants to get the current
system pulse_id.
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#!/bin/bash
VERSION=1.0.0
docker build --no-cache=true -f debug.Dockerfile -t paulscherrerinstitute/std-stream-send-sim .
docker tag paulscherrerinstitute/std-stream-send-sim paulscherrerinstitute/std-stream-send-sim:$VERSION
docker login
docker push paulscherrerinstitute/std-stream-send-sim:$VERSION
docker push paulscherrerinstitute/std-stream-send-sim
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FROM paulscherrerinstitute/sf-daq_phdf5:1.0.0
COPY . /sf_daq_buffer/
RUN mkdir /sf_daq_buffer/build && \
cd /sf_daq_buffer/build && \
cmake3 .. && \
make std-stream-send
WORKDIR /sf_daq_buffer/build
ENTRYPOINT ["/sf_daq_buffer/build/std_stream"]
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#ifndef SF_DAQ_BUFFER_UDPRECVCONFIG_HPP
#define SF_DAQ_BUFFER_UDPRECVCONFIG_HPP
#include <rapidjson/istreamwrapper.h>
#include <rapidjson/document.h>
#include <rapidjson/stringbuffer.h>
#include <string>
#include <fstream>
struct StreamSendConfig {
static StreamSendConfig from_json_file(const std::string& filename) {
std::ifstream ifs(filename);
rapidjson::IStreamWrapper isw(ifs);
rapidjson::Document config_parameters;
config_parameters.ParseStream(isw);
return {
config_parameters["detector_name"].GetString(),
config_parameters["detector_type"].GetString(),
config_parameters["n_modules"].GetInt(),
config_parameters["start_udp_port"].GetInt(),
};
}
const std::string detector_name;
const std::string detector_type;
const int n_modules;
const int start_udp_port;
};
#endif //SF_DAQ_BUFFER_UDPRECVCONFIG_HPP
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namespace stream_config
{
// N of IO threads to receive data from modules.
const int STREAM_ZMQ_IO_THREADS = 1;
// How long should the RECV queue be.
const size_t STREAM_RCVHWM = 100;
const int PROCESSING_ZMQ_SNDHWM = 10;
// Keep the last second of pulses in the buffer.
const int PULSE_ZMQ_SNDHWM = 100;
// Number of pulses between each statistics print out.
const size_t STREAM_STATS_MODULO = 1000;
}
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#include <iostream>
#include <zmq.h>
#include "stream_config.hpp"
#include <chrono>
#include <thread>
#include "RamBuffer.hpp"
using namespace std;
using namespace stream_config;
int main (int argc, char *argv[])
{
auto ctx = zmq_ctx_new();
zmq_ctx_set(ctx, ZMQ_IO_THREADS, STREAM_ZMQ_IO_THREADS);
auto sender = zmq_socket(ctx, ZMQ_PUSH);
const int sndhwm = PROCESSING_ZMQ_SNDHWM;
if (zmq_setsockopt(
sender, ZMQ_SNDHWM, &sndhwm, sizeof(sndhwm)) != 0) {
throw runtime_error(zmq_strerror(errno));
}
const int linger = 0;
if (zmq_setsockopt(
sender, ZMQ_LINGER, &linger, sizeof(linger)) != 0) {
throw runtime_error(zmq_strerror(errno));
}
if (zmq_bind(sender, "tcp://127.0.0.1:10000") != 0) {
throw runtime_error(zmq_strerror(errno));
}
RamBuffer image_buffer(config.detector_name + "_assembler",
sizeof(ImageMetadata), assembler.get_image_n_bytes(), 1);
while (true) {
image_id = 123;
zmq_send(sender,
ram_buffer.get_slot_meta(image_id),
sizeof(ImageMetadata), ZMQ_SNDMORE);
zmq_send(sender,
ram_buffer.get_slot_data(image_id),
buffer_config::MODULE_N_BYTES * 4, 0);
pulse_id++;
std::this_thread::sleep_for(std::chrono::milliseconds(10));
}
}
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add_executable(std-stream-send-tests main.cpp)
target_link_libraries(std-stream-send-tests
std-stream-send-lib
gtest
)
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#include "gtest/gtest.h"
using namespace std;
int main(int argc, char **argv) {
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}