THttpServer for ROOT Bertrand Bellenot, CERN Sergey Linev, GSI - PowerPoint PPT Presentation

THttpServer for ROOT Bertrand Bellenot, CERN Sergey Linev, GSI Darmstadt 28.02.2014

JSRootIO Written on JavaScript, works in all major browsers  IE, Firefox, Opera, Safari, Android, …  Allows to draw many kinds of ROOT objects  TH1, TH2, TH3, TProfile, TGraph, THStack, TCanvas  Demonstrator:  http://web-docs.gsi.de/~linev/JSRootIO/index_local.htm  Interactive graphics directly in the browser:  changing of draw style, zooming, bins info  update of statistic in stat box  different context menu commands  Main aim – display objects from ROOT files  PRO - no need for special code on the web server  CONTRA – not possible to update data dynamically  28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 2

JSRootIO for online?  JSRootIO is file-based  difficult to use for online tasks  not really scales for big systems  Much more benefits if will run online  one would see live results from running experiment from any place of the world  One need special web application, which can provide online data to JSRootIO 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 3

Web server for ROOT  THttpServer class provides web server for arbitrary ROOT application  In any place of ROOT macro: root [0] .x $ROOTSYS/tutorials/hsimple.C root [1] new THttpServer();  No any changes in ROOT framework are required  No any changes in user code are required 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 4

hsimple.C in web browser 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 5

Main classes  TRootSniffer - `sniffer`for objects hierarchies in TFolder, TFile/TDirectory, TTree, TCollection  THttpEngine – abstract class for implementing http protocol TMongoose – embeddable web server, based on   https://github.com/valenok/mongoose TFastCgi – FastCGI protocol implementation  supported by all major web servers like Apache, MS IIS, lighttpd, ...   THttpServer – central class receive http requests from engine(s)  http requests processed by sniffer  takes care about threads safety  28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 6

THttpServer Any object can be registered in TFolder structure:  root [5] h1 = new TH1I(“h1”, “title”, 5, 0, 5);  root [6] serv- >Register(“folder”, h1);  Following http requests are processed:  http://host:654/ROOT/h.xml   xml file with objects hierarchy, used to build tree structures in browser http://host:654/ROOT/h1/get.bin   binary zipped data, produced by object streaming http://host:654/ROOT/StreamerInfo/get.bin   binary zipped data of current streamer infos http://host:654/ROOT/h1/get.png?w=100&h=100   png image, produced from TCanvas http://host:654/ROOT/   returns generic (or user-defined) html page, shown before 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 7

FastCGI support Protocol for interfacing interactive programs with web servers  Supported by all major web servers  Apache, lighttpd, MS IIS, Cherokee, Hiawatha, LiteSpeed, Kerio,  Nginx, Resin, Roxen, Zeus ... One benefits from common infrastructure  user access, security, encryption, balancing, ...  Can run in parallel to HTTP server  ROOT http FastCGI Apache http 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 8

Project state  Developed since mid 2013  Works with ROOT 5.14 and 6.00  Tested on Linux and Windows  No external dependencies  mongoose is just two source files  mongoose is GPL2, can be replaced by civetweb with MIT license  FastCGI is optional, provided by all Linux distributions  For the moment available on: https://subversion.gsi.de/dabc/http/ 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 9

Current applications  Integrated into DABC  DABC is DAQ framework, used in different experiments  now also provides generic web interface for online software  DAQ – DABC, MBS (GSI standard DAQ)  slow control – FESA (CERN/GSI accelerator control), EPICS, DIM  online analysis – Go4, ROOT  Integrated with Go4  Go4 is analysis framework with QtRoot online monitoring interface  now also web interface without changing user-code  Evaluated by different groups in GSI:  HADES, SuperFRS, R3B  Could be used in AMORE framework of ALICE 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 10

Possible developments Replace mongoose by ROOT TThread/TSocket classes  many parts of original mongoose code can be reused, ~1 month of work  Implement caching on the server  preventing application from overload, ~1 week of work  Implement more http requests  http://host:654/ROOT/h1/get.xml  convert object into xml with TBufferXML, ~1 hour of work  http://host:654/ROOT/h1/get.json  stream object into JSON representation directly  no need for ROOT I/O in JavaScript  one need TBufferJSON class, ~2 weeks of work  http://host:654/ROOT/h1/fTitle/get.txt  access to object members in simple text form  mostly implemented, ~3 days of work  http://host:654/ROOT/Cmd/Reset/exe.cmd?par1=10  provide command interface via http protocol  any user-defined commands with extra parameters  user authentication with standard http methods  28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 11

More than web interface  One can use http protocol to communicate with any running ROOT application  From any script: wget http://host:654/ROOT/obj/fPar/get.txt wget http://host:654/ROOT/obj/fPar/set.txt?value=1  For many cases no need for extra sockets and special protocols 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 12

Backup slides 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 13

Use case – HADES DABC TRB Event builder EvBld HYDRA2 stream TRB hld files TRB TRB hld Event builder TRB Event builder hld TRB go4 gui TRB hld Event builder TRB TRB TRB web browser 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 14

Use case – HADES  DABC as DAQ system  collects data from TRBs  store HLD files  deliver data to online analysis  Stream event source to connect DAQ  HYDRA2 analysis gets data directly via socket instead of temporary hld files  THttpServer for analysis monitoring  no any change in HYDRA2 itself  Monitor DAQ and analysis via same interface 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 15

Use case – HADES HYDRA2 DABC HYDRA2 Histograms Event builder HYDRA2 EvBld stream collector HYDRA2 HYDRA2 hld files  Online analysis  Many processes in parallel  doing same events or different events  Histograms collector (to be done) 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 16

Go4ExampleSimple in web browser 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 17

Use case – DAQ and slow-control middleware ROOT online go4 online analysis analysis beam DABC FESA profiles http DAQ status and log slow-control information variables MBS MBS DABC EPICS 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 18

Use case – several DABC nodes MBS DABC socket http MBS DABC FastCGI Master FESA http go4 online DABC analysis socket http Preferable EPICS FastCGI Apache MBS DABC http ROOT socket http analysis Optional FastCGI ROOT analysis 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 19

Alternatives to web browser web browser DABC SOAP, JSON DABC API http socket go4 gui with native ROOT graphics console-based tools 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 20

How it works – hierarchy request wget http://lxg0538:8090/FESA/h.xml <?xml version="1.0"?> <dabc version="2" xmlns:dabc="http://dabc.gsi.de/xhtml" path="/FESA/"> <FESA> <Monitor dabc:producer="dabc://lxg0538:1237/fesa_monitor"> <GetMeasVoltage dabc:history="100"/> <GetMeasCurrent dabc:history="100"/> <GetMeasWeight dabc:history="100"/> </Monitor> <Test dabc:producer="dabc://lxg0538:1237/fesa"> <BeamProfile dabc:hash="74647" dabc:kind="FESA.2D"/> <BeamRate dabc:kind="rate"/> <BeamRate2 dabc:history="100" dabc:kind="rate"/> <TestRate dabc:history="100" dabc:kind="rate"/> <StreamerInfo dabc:hash="32" dabc:kind="ROOT.TList"/> <BeamRoot dabc:hash="7464700" dabc:kind="ROOT.TH2I" dabc:master="StreamerInfo"/> <ImageRoot dabc:kind="image.png"/> </Test> </FESA> </dabc> 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 21

How it works – item request wget http://lxg0538:8090/FESA/Test/TestRate/get.xml server item request <Reply xmlns:dabc="http://dabc.gsi.de/xhtml" itemname="/FESA/Test/TestRate" dabc:version="75177"> <get dabc:history="100" dabc:kind="rate" time="2013-09-20T12:12:43.874Z" value="96.00"/> </Reply> 28.02.2014 B.Bellenot, S.Linev, THttpServer for ROOT 22