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A header-only C write client for InfluxDB.

• Supported versions:
  • InfluxDB v0.9 ~ v1.4
  • Check yourself while using other versions.

• Exactly small:
  • Less than 300 lines and only about 10KB.
• Easy to use:
  • It's designed to be used without extra studies.
• Easy to assemble:
  • Only a tiny header file needs to be included.
• No dependencies:
  • Unless std C libraries.
• Under serious testing:
  • Uses gtest &mockcpp

• The very simple thing you should do before using is only:

  #include"influxdb.h"

• You should according to thewrite syntax while writing series(metrics).

  measurement[,tag-key=tag-value...] field-key=field-value[,field2-key=field2-value...] [unix-nano-timestamp]

• You can rapidly start writing series by using one of the following examples:

• Client configurations:

  influx_client_tc;c.host=strdup("127.0.0.1");c.port=8086;c.db=strdup("db");c.usr=strdup("usr");c.pwd=strdup("pwd");

• Under C99, you can use:

  influx_client_tc= {    .host=strdup("127.0.0.1"),    .port=8086,    .db=strdup("db"),    .usr=strdup("usr"),    .pwd=strdup("pwd")};

• Then send out the series by callingpost_http:

  post_http(&c,INFLUX_MEAS("foo"),INFLUX_TAG("k","v"),INFLUX_TAG("x","y"),INFLUX_F_INT("x",10),INFLUX_F_FLT("y",10.3,2),INFLUX_F_FLT("z",10.3456,2),INFLUX_F_BOL("b",10),INFLUX_TS(1512722735522840439),INFLUX_END);

  • NOTE:
    • 3rd parameter ofINFLUX_F_FLT() isprecision for floating point value.
    • usr andpwd is optional for authorization.
    • INFLUX_END is the delimiter for variable arguments list thatshould not be ommitted.

• The series sent is:

  foo,k=v,x=y x=10i,y=10.30,z=10.35,b=t 1512722735522840439

• You could changepost_http tosend_udp for UDP request. And onlyhost andport are required for UDP operation.

  influx_client_tc= {strdup("127.0.0.1"),8091,NULL,NULL,NULL};send_udp(&c,INFLUX_MEAS("foo"),INFLUX_TAG("k","v"),INFLUX_F_INT("x",10),INFLUX_END);

• Bulk/batch write is also supported:

  send_udp(&c,INFLUX_MEAS("foo"),// series 1INFLUX_F_INT("x",10),INFLUX_MEAS("foo"),// series 2INFLUX_F_FLT("y",10.3,2),INFLUX_END);

• The series sent are:

  foo x=10ibar y=10.30

• If measurement data is sent from within a loop, but higher write performanceis needed, one has to format each measurement separately, then at the endsend the formatted line to the database. This example sends 10 measurementswith a single http request:

  influx_client_tc= {strdup("127.0.0.1"),8091,NULL,NULL,NULL};char*line=NULL;intlen=0;intused=0;for (inti=0;i<10;++i) {used=format_line(line,&len,used,INFLUX_MEAS("foo"),INFLUX_TAG("k","v"),INFLUX_F_INT("x",i),INFLUX_END);}post_http_send_line(&c,line,used);

• Add more test cases for send functions.
• Supports DSN initializatin for influx_client_t.
• Add query function.
• Do not need to connect every time.

• Please feel free to use influxdb-c.
• Looking forward to your suggestions.
• If your project is using influxdb-c, you can show your project or company here by creating a issue or let me know.