# Tarolog

Library for flexible configuration of tarantool logs. Allows you to set your own log format or choose from builtin formats.
Supports "data injectors" for enrichment log records with any data (e.g. instance-id or request-id).
All formats are applying to tarantool internal logs as well.

### Builtin formats

- JsonRaw - json logs. This format is as close as possible to an original tarantool 'json' format.
- Json - json logs, use `serde` library for a log record generation.
- Plain - plain text. This format is as close as possible to an original tarantool 'plain' format.

Also, you can implement your own format.

### Benchmark

|                    | generate file size (lines per sec) <br/> bigger is better | generated stdout output (mb per sec) <br/> bigger is better |
|--------------------|-----------------------------------------------------------|-------------------------------------------------------------|
| tarantool-json     | 144135                                                    | 49,675                                                      |
| tarolog-json       | 203785                                                    | 82                                                          |
| tarolog-json-serde | 188217                                                    | 70,25                                                       |
| tarantool-plain    | 210876                                                    | 29,475                                                      |
| tarolog-plain      | 231691                                                    | 29,95                                                       |

See a "bench" package for familiarize with benchmark process.

### Example

In this example we use json format with injectors that propagate two fields:
- key: "additional data", value: true
- key: "request_id", value: {request id extracted from fiber local storage}

```rust
use tarolog;
use tarolog::Format;
use tarantool;
use tarantool::ffi;
use std::collections::HashMap;
use log::info;

fn main() {
    tarolog::set_default_logger_format(Format::Json(Some(|| {
        let mut additional_info =
            HashMap::from([("additional data".to_string(), serde_json::Value::Bool(true))]);
        
        // lua available only in tx thread, check it
        let cord_is_main = unsafe { ffi::tarantool::cord_is_main() };
        if cord_is_main {
            let lua = tarantool::lua_state();
            if let Ok(Some(rid)) = lua.eval("return require('fiber').self().storage['rid']") {
                additional_info.insert("request_id".to_string(), serde_json::Value::String(rid));
            }
        }

        additional_info
    })));
    
    info!("now new format is installed");
}
```

### Tests

[tarantool-test](https://crates.io/crates/tarantool-test) is required.

#### Run unit tests

```shell
cargo test
```

#### Run integration tests

```shell
cargo build; tarantool-test -p ./target/debug/libtests.so -- -i tests/test_init.lua
```

#### All tests

```shell
make test
```