README.md
gelf pro
=============
`gelf-pro` - Graylog2 client library for Node.js.
Sends logs to Graylog2 server in GELF (Graylog Extended Log Format) format.
**Features:**
- JS object marshalling
- UDP/TCP/TLS support
- Filtering, Transforming, Broadcasting.
## Installation
```
"dependencies": {
"gelf-pro": "~1.3" // see the "releases" section
}
```
`npm install gelf-pro` (**ALL** node.js versions are supported [0.x to 2x.x] :)
Library depends on: `lodash#~4.17`
## Initialization
```javascript
var log = require('gelf-pro');
```
### Adapters
> [!WARNING]
> To ensure consistent behavior, **none of the existing adapters re-use the socket connection**. Re-using socket connections can lead to resource leakage, complexity in state management, concurrency issues, security risks, and may not always provide significant performance benefits.
> It's often simpler and safer to establish new connections as needed rather than re-using existing ones, ensuring better resource utilization and reducing potential complications in network communication.
>
> There are multiple ([1](https://github.com/kkamkou/node-gelf-pro/pull/68), [2](https://github.com/fdelayen/node-gelf-pro/commit/b52b4b6b1ff26772314b8673dd6fd724c0937caa)) variants available for you to borrow from and create a new adapter. [See related section](#third-party-adapters).
- UDP (with deflation and chunking)
- Input: `GELF UDP`
- TCP
- Input: `GELF TCP` (with `Null frame delimiter`)
- TCP via TLS(SSL)
- Input: `GELF TCP` (with `Null frame delimiter` and `Enable TLS`)
> [!NOTE]
> Within a more or less stable network (which is most likely), I would recommend using the `udp` adapter.
> I would also recommend it for an average to high-loaded project.
> For sensitive information, the `tcp-tls` adapter is recommended.
### Configuration
```javascript
// simple
log.setConfig({adapterOptions: {host: 'my.glog-server.net'}});
// advanced
log.setConfig({
fields: {facility: "example", owner: "Tom (a cat)"}, // optional; default fields for all messages
filter: [], // optional; filters to discard a message
transform: [], // optional; transformers for a message
broadcast: [], // optional; listeners of a message
levels: {}, // optional; default: see the levels section below
aliases: {}, // optional; default: see the aliases section below
adapterName: 'udp', // optional; currently supported "udp", "tcp" and "tcp-tls"; default: udp
adapterOptions: { // this object is passed to the adapter.connect() method
// common
host: '127.0.0.1', // optional; default: 127.0.0.1
port: 12201, // optional; default: 12201
// ... and so on
// tcp adapter example
family: 4, // tcp only; optional; version of IP stack; default: 4
timeout: 1000, // tcp only; optional; default: 10000 (10 sec)
// udp adapter example
protocol: 'udp4', // udp only; optional; udp adapter: udp4, udp6; default: udp4
// tcp-tls adapter example
key: fs.readFileSync('client-key.pem'), // tcp-tls only; optional; only if using the client certificate authentication
cert: fs.readFileSync('client-cert.pem'), // tcp-tls only; optional; only if using the client certificate authentication
ca: [fs.readFileSync('server-cert.pem')] // tcp-tls only; optional; only for the self-signed certificate
}
});
```
> `log.setConfig` merges the data. Therefore, you can call it multiple times.
### Basic functionality
```javascript
var extra = {tom: 'cat', jerry: 'mouse', others: {spike: 1, tyke: 1}};
log.info("Hello world", extra, function (err, bytesSent) {});
log.info("Hello world", function (err, bytesSent) {});
log.info("Hello world", extra);
log.info("Hello world");
log.error('Oooops.', new Error('An error message'));
// ^-- extra becomes: {short_message: 'Oooops.', _error_message: 'An error message', _error_stack: Error's stack}
log.error(new Error('An error message'));
// ^-- extra becomes: {short_message: 'An error message', full_message: Error's stack}
log.message(new Error('An error message'), 3); // same as previous
```
##### Extra
In case `extra` [is a plain object](https://lodash.com/docs#isPlainObject),
the library converts it to a readable format. Other values [are converted to string](https://lodash.com/docs#toString).
The acceptable format of a key is: `^[\w-]$`
```javascript
log.info(
'a new msg goes here',
{me: {fname: 'k', lname: 'k', bdate: new Date(2000, 01, 01)}}
);
// ^-- extra becomes: {_me_fname: 'k', _me_lname: 'k', _me_bdate: 'Tue Feb 01 2000 00:00:00 GMT+0100 (CET)'}
```
##### Filtering
Sometimes we have to discard a message which is not suitable for the current environment. It is `NOT` possible to modify the data.
```javascript
log.setConfig({
filter: [
function (message) { // rejects a "debug" message
return (message.level < 7);
}
]
});
```
##### Transforming
`transforming` happens after `filtering`. It is possible to modify the data.
```javascript
log.setConfig({
transform: [
function (message) { // unwind an error
if (_.isError(message.error)) {
message.error = {message: message.error.message, stack: message.error.stack};
}
return message;
}
]
});
```
##### Broadcasting
`broadcasting` happens after `transforming`. It is `NOT` possible to modify the data.
```javascript
log.setConfig({
broadcast: [
function (message) { // broadcasting to console
console[message.level > 3 ? 'log' : 'error'](message.short_message, message);
}
]
});
```
### Levels ([1](https://httpd.apache.org/docs/current/mod/core.html#loglevel), [2](https://logging.apache.org/log4j/2.0/log4j-api/apidocs/org/apache/logging/log4j/Level.html), [3](http://stackoverflow.com/questions/2031163/when-to-use-the-different-log-levels))
Default:
`{emergency: 0, alert: 1, critical: 2, error: 3, warning: 4, notice: 5, info: 6, debug: 7}`
Example: `log.emergency(...)`, `log.critical(...)`, etc.
Custom example: `{alert: 0, notice: 1, ...}`
### Third party adapters
You can force using custom adapter by setting the `adapter` right after initialisation. The [signature](lib/adapter/abstract.js) might be found here.
```javascript
var log = require('gelf-pro');
var myFancyAdapter = require('...');
log.adapter = myFancyAdapter;
// (!) adapterName and adapterOptions will be ignored
```
### Aliases
Default: `{log: 'debug', warn: 'warning'}`
Example: `log.log(...) -> log.debug(...)`, `log.warn(...) -> log.warning(...)`, etc.
Custom example: `{red: 'alert', yellow: 'notice', ...}`
### Tests
#### Cli
```bash
npm install
npm test
```
#### Docker
```bash
[sudo] docker build --no-cache -t node-gelf-pro .
[sudo] docker run -ti --rm -v "${PWD}:/opt/app" -w "/opt/app" node-gelf-pro
```
#### Contributors
- [corbinu](https://github.com/corbinu)
- [joelharkes](https://github.com/joelharkes)
- [mkalam-alami](https://github.com/mkalam-alami)
#### License
[MIT](LICENSE)