shinypebbles / shelly

Collect and process data from Shelly in an Oracle database

Shelly

Collect and process data from Shelly in an Oracle database

This project collects data from the Shelly Plus Plug S and stores it in an Oracle database (v12.1). The data is displayed in a graph using Oracle APEX (v20.1).

The Shelly Plug delivers data in JSON, so let's create a data model to store the data. The owner of the tables is: SHELLY.

CREATE TABLE  "PLUG" 
   (	"SEQ#" NUMBER NOT NULL ENABLE, 
	"HOSTNAME" VARCHAR2(40) NOT NULL ENABLE, 
	"NAME" VARCHAR2(40), 
	 CONSTRAINT "PLUG_PK" PRIMARY KEY ("SEQ#")
  USING INDEX  ENABLE
   )
/

CREATE TABLE  "PLUGSTATUS" 
   (	"PLUGSEQ#" NUMBER, 
	"DATA" CLOB, 
	 CONSTRAINT "PLUGSTATUS_JSON_CHK" CHECK (data IS JSON) ENABLE
   )
/
ALTER TABLE  "PLUGSTATUS" ADD CONSTRAINT "PLUGSTATUS_FK1" FOREIGN KEY ("PLUGSEQ#")
	  REFERENCES  "PLUG" ("SEQ#") ENABLE
/

CREATE INDEX  "PLUGSTATUS_IND1" ON  "PLUGSTATUS" ("PLUGSEQ#")
/

The parent table contains an ID called seq#, the hostname of the Shelly plugs and a name, for example 'freezer'. The child table contains a reference to the parent ID and the collected data in JSON-format.

The data is collected through a http REST API call. First we need to allow the table owner SHELLY http-access to hosts in the network.

BEGIN
  DBMS_NETWORK_ACL_ADMIN.append_host_ace (
    host       => '*', 
    lower_port => 80,
    upper_port => 80,
    ace        => xs$ace_type(privilege_list => xs$name_list('http'),
                              principal_name => 'SHELLY',
                              principal_type => xs_acl.ptype_db)); 
END;
/

Documentation of the JSON-format. Here is an example of the returned JSON:

{"id":0, "source":"init", "output":true, "apower":0.0, "voltage":236.4, "current":0.047, "aenergy":{"total":3158.258,"by_minute":[0.000,0.000,0.000],"minute_ts":1684960207},"temperature":{"tC":37.5, "tF":99.5}}

The following procedure fetches the data and inserts it in the database.

create or replace PROCEDURE getplugstatus AS
  req   UTL_HTTP.REQ;
  resp  UTL_HTTP.RESP;
  value VARCHAR2(1024);
BEGIN
  for c1_rec in (select seq# 
    , hostname
    from plug
    order by 1)
  LOOP
    BEGIN
      req := UTL_HTTP.BEGIN_REQUEST('http://'||c1_rec.hostname||'/rpc/Switch.GetStatus?id=0');
      UTL_HTTP.SET_HEADER(req, 'User-Agent', 'Mozilla/4.0');
      resp := UTL_HTTP.GET_RESPONSE(req);
      LOOP
        UTL_HTTP.READ_LINE(resp, value, TRUE);
        DBMS_OUTPUT.PUT_LINE(value);
        insert into plugstatus(plugseq#, data) values (c1_rec.seq#, value);
      END LOOP;
      UTL_HTTP.END_RESPONSE(resp);
    EXCEPTION
      WHEN UTL_HTTP.END_OF_BODY THEN
        UTL_HTTP.END_RESPONSE(resp);
      WHEN others THEN
        DBMS_OUTPUT.PUT_LINE('other error');
    END;
  END LOOP;
END;

Create a job to collect the data every minute.

BEGIN
    DBMS_SCHEDULER.CREATE_JOB (
            job_name => '"SHELLY"."JOB_GET_STATUS"',
            job_type => 'PLSQL_BLOCK',
            job_action => 'begin getplugstatus; end;',
            number_of_arguments => 0,
            start_date => TO_TIMESTAMP_TZ('2015-11-17 21:35:00.000000000 EUROPE/AMSTERDAM','YYYY-MM-DD HH24:MI:SS.FF TZR'),
            repeat_interval => 'FREQ=MINUTELY',
            end_date => NULL,
            enabled => FALSE,
            auto_drop => TRUE,
            comments => 'Get Shelly status every minute');
 
    DBMS_SCHEDULER.SET_ATTRIBUTE( 
             name => '"SHELLY"."JOB_GET_STATUS"', 
             attribute => 'store_output', value => TRUE);
    DBMS_SCHEDULER.SET_ATTRIBUTE( 
             name => '"SHELLY"."JOB_GET_STATUS"', 
             attribute => 'logging_level', value => DBMS_SCHEDULER.LOGGING_OFF);
      
    DBMS_SCHEDULER.enable(
             name => '"SHELLY"."JOB_GET_STATUS"');
END;

The JSON minute_ts field is in Unix epoch format in UTC. So it needs to be converted to CET or CEST. For this a function is created.

create or replace function epoch2cet_cest
( pl_epoch in number)
  return date
is
  pl_date date;
  pl_start date;
  pl_end date;
  pl_offset number;
begin
  pl_date:=TO_DATE('1970-01-01', 'YYYY-MM-DD') + NUMTODSINTERVAL(pl_epoch, 'SECOND');
  pl_start:=NEXT_DAY(to_date('24-03-'||to_char(sysdate, 'YYYY'), 'DD-MM-YYYY'),'SUNDAY');
  pl_end:=NEXT_DAY(to_date('24-10-'||to_char(sysdate, 'YYYY'), 'DD-MM-YYYY'),'SUNDAY');
  if pl_date>pl_start and pl_date<pl_end then
    pl_offset:=2; --Central European Summer Time (CEST)
  else
    pl_offset:=1; --Central European Time (CET)
  end if;
  return pl_date+pl_offset/24;
end epoch2cet_cest;

The data needed for the graph is selected from the JSON data in the child table.

select to_number(S.data.apower) as power
, epoch2cet_cest(S.data.aenergy.minute_ts) as date_time
, P.seq#
from plug P, plugstatus S
where P.seq#=S.plugseq#
  and P.seq#=:P88_SEQ
  and trunc(epoch2cet_cest(S.data.aenergy.minute_ts))=trunc(to_date(:P88_DATUM))
order by epoch2cet_cest(S.data.aenergy.minute_ts)

Line graph of the freezer power consumption in one day.