influxdb-cpp-2.0

A header-only C++ query & write client for InfluxDB 2.0.

Support versions:
- InfluxDB v2.0
- Incompatible with versions 1.x
- Check yourself while using future versions.

Why use influxdb-cpp?

Exactly-small:
- Less than 300 lines and only 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 STL and std C libraries.

Examples

Before using

The very simple thing you should do before using is only:
```
#include "influxdb.hpp"
```

Writing example

You should refer to the write 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 according to the following example.
```
influxdb_cpp::server_info si("127.0.0.1", 8086, "org", "token", "bucket");
influxdb_cpp::builder()
    .meas("foo")
    .tag("k", "v")
    .tag("x", "y")
    .field("x", 10)
    .field("y", 10.3, 4)
    .field("z", 10.3456)
    .field("b", !!10)
    .timestamp(1512722735522840439)
    .post_http(si);
```
- Remarks:
  - 3rd parameter precision of field() is optional for floating point value, and default precision is defined in the top of the header.
  - The token must have access to write (and/or read) from the specified organization and bucket.
  - Although bucket is an optional parameter for a server info object, it is required for database writes.

The series sent is:

foo,k=v,x=y x=10i,y=10.30,z=10.346,b=t 1512722735522840439

Bulk/batch/multiple insert also supports:

influxdb_cpp::builder()
    .meas("foo")  // series 1
    .field("x", 10)

    .meas("bar")  // series 2
    .field("y", 10.3)
    .post_http(si);

The series sent are:
```
foo x=10i
bar y=10.30
```

Query example

And you can query series using the Flux query language.

influxdb_cpp::server_info si("localhost", 8086, "spartans", "my_token", "");

string resp;
string query("from(bucket: \\\"SR-20\\\")|> range(start: -5m)|>filter(fn: (r)=>r[\\\"_measurement\\\"] == \\\"cpu\\\")|>filter(fn: (r) => r[\\\"_field\\\"] == \\\"usage_user\\\")");

influxdb_cpp::query(resp, query, si);

NOTE: The query is sent in a JSON key-pair, therefore there must be no newlines/tabs, and " must be double-escaped as \\\"!
The results are returned in CSV format. A column, table, separates different measurements

Remarks for Windows

You should init socket environment by yourself under Windows.
- FYR: MSDN doc for WSAStartup

TODO

Add more test cases.
Supports DSN initializatin for server_info.
Do not need to connect every time.

Misc

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

sethcall / influxdb-cpp-2