This package is API gateway for generalpvaccess-datasource.
It receives http requests from generalpvaccess-datasource and retrieves data from pvAccess RPC server.
This package supports Python 3.7 or later.
See docmentation
# clone the repository
git clone https://github.com/sasaki77/gfhttpva
cd gfhttpva
# install gfhttpva
pip install -e .Simple usage is below.
export FLASK_APP=gfhttpva
export FLASK_ENV=development
export GFHTTPVA_CONFIG=/absolute/path/to/config/file
flask run --port=3003See here for more flask information.
Refer config file example gfhttpva.cfg.
pvAccess Server should implement 3 channels:
get RPCshould return metrics or table based on inputannotation RPCshould return annotationssearch RPCused by the find metric options on the query tab in Grafana panels (optional)
Each RPC channel names are passed from generalpvaccess-datasource.
Example request
starttime, endtime and entity are necessary arguments and their labels are passed from generalpvaccess-datasource, i.e. these 3 arguments are necessary but their labels are arbitrary. Any other arguments are optional which are determined by generalpvaccess-datasource settings.
structure
string starttime 2018-05-16T07:08:44
string endtime 2018-05-16T13:08:44
string entity point3
string begin 5
NTURI style request is also available if generalpvaccess-datasource passes nturi_style as True.
epics:nt/NTURI:1.0
string scheme pva
string path PATH:TO:NTURI:STYLE:RPC
structure query
string starttime 2018-05-16T07:08:44
string endtime 2018-05-16T13:08:44
string entity point3
string begin 5
Example timeserie reponse
timeserie response must has value, secondsPastEpoch and nanoseconds column. Each element name of structure value must be columnX or consistent with labels.
epics:nt/NTTable:1.0
string[] labels [value,secondsPastEpoch,nanoseconds]
structure value
double[] column0 [5, 6, 7]
double[] column1 [1526422268, 1526433068, 1526443868] // unixtimestamp in seconds
double[] column2 [123456, 135246, 124536]
Example table reponse
The table can be composed of any columns but each element name of structure value must be columnX or consistent with labels.
epics:nt/NTTable:1.0
string[] labels [value,secondsPastEpoch,nanoseconds,status,severity]
structure value
double[] column0 [1.1, 1.2, 2.0]
double[] column1 [1460589140, 1460589141, 1460589142]
double[] column2 [164235768, 164235245, 164235256]
double[] column3 [0, 0, 1]
double[] column4 [0, 0, 3]
Example request
structure
string starttime 2018-05-16T07:08:44
string endtime 2018-05-16T13:08:44
string entity test
NTURI style request is also available if generalpvaccess-datasource passes nturi_style as True.
epics:nt/NTURI:1.0
string scheme pva
string path PATH:TO:NTURI:STYLE:RPC
structure query
string starttime 2018-05-16T07:08:44
string endtime 2018-05-16T13:08:44
string entity test
Example response
epics:nt/NTTable:1.0
string[] labels [time,title,tags,text]
structure value
ulong[] column0 [1526439600000] // unixtimestamp in milliseconds
string[] column1 [Title]
string[] column2 [tag1,tag2]
string[] column3 [Text]
Example request
structure
string name entity
string entity s
NTURI style request is also available if generalpvaccess-datasource passes nturi_style as True.
epics:nt/NTURI:1.0
string scheme pva
string path PATH:TO:NTURI:STYLE:RPC
structure query
string name entity
string entity s
Example response
epics:nt/NTScalarArray:1.0
string[] value [sine,string]
Before runnging tests, test pvAccess RPC server must be running.
python tests/pvaserver/run.pyRun without coverage:
pip install pytest
pytestRun with coverage:
pip install pytest pytest-cov
pytest --cov gfhttpva
coverage report -m