# Triglav::Agent::Vertica

Triglav Agent for Vertica

## Requirements

* Ruby >= 2.3.0

## Prerequisites

* Vertica table must have a DATE column for `daily` resource monitor
* Vertica table must have a TIMESTAMP or TIMESTAMPTZ column for `hourly` resource monitor
* Vertica view is not supported (since `epoch` column can not be retrieved)

## Installation

Add this line to your application's Gemfile:

```ruby
gem 'triglav-agent-vertica'
```

And then execute:

    $ bundle

Or install it yourself as:

    $ gem install triglav-agent-vertica

## CLI

```
Usage: triglav-agent-vertica [options]
    -c, --config VALUE               Config file (default: config.yml)
    -s, --status VALUE               Status stroage file (default: status.yml)
    -t, --token VALUE                Triglav access token storage file (default: token.yml)
        --dotenv                     Load environment variables from .env file (default: false)
    -h, --help                       help
        --log VALUE                  Log path (default: STDOUT)
        --log-level VALUE            Log level (default: info)
```

Run as:

```
TRIGLAV_ENV=development bundle exec triglav-agent-vertica --dotenv -c config.yml
```

## Configuration

Prepare config.yml as [example/config.yml](./example/config.yml).

You can use erb template. You may load environment variables from .env file with `--dotenv` option as an [example/example.env](./example/example.env) file shows.

### serverengine section

You can specify any [serverengine](https://github.com/fluent/serverengine) options at this section

### triglav section

Specify triglav api url, and a credential to authenticate.

The access token obtained is stored into a token storage file (--token option).

### vertica section

This section is the special section for triglav-agent-vertica.

* **monitor_interval**: The interval to watch tables (number, default: 60)
* **connection_info**: key-value pairs of vertica connection info where keys are resource URI pattern in regular expression, and values are connection infomation

### Specification of Resource URI

Resource URI must be a form of:

```
vertica://#{host}:#{port}/#{db}/#{schema}/#{table}
```

URI also accepts query parameters of `date`, `timestamp`, and `where`.

* **date** (string): date column name (default: `d`)
* **timestamp** (string): timestamp column name (defualt: `t`)
* **where** (hash): where conditions (default: nil)
 * A value looks like an integer string is treated as an integer such as `1`
 * If you want to treat it as as string, surround with double quote or single quote such as `'0'`
 * A value does not look like an integer is treated as a string such as `foo`
 * Only equality operator is supported now

ex)

```
?date=d&timestamp=t&where[id]=0&where[d]=2016-12-30
```

## How it behaves

1. Authenticate with triglav
  * Store the access token into the token storage file
  * Read the token from the token storage file next time
  * Refresh the access token if it is expired
2. Repeat followings in `monitor_interval` seconds:
3. Obtain resource (table) lists of the specified prefix (keys of connection_info) from triglav.
4. Connect to vertica with an appropriate connection info for a resource uri, and find tables which are newer than last check.
5. Store checking information into the status storage file for the next time check.

## Development

### Prepare

```
./prepare.sh
```

Edit `.env` or `config.yml` file directly.

### Start

Start up triglav api on localhost.

Run triglav-anget-vertica as:

```
TRIGLAV_ENV=development bundle exec triglav-agent-vertica --dotenv --debug -c example/config.yml
```

The debug mode with --debug option ignores the `last_epoch` value in status file.

## Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/triglav-workflow/triglav-agent-vertica. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](http://contributor-covenant.org) code of conduct.


## License

The gem is available as open source under the terms of the [MIT License](http://opensource.org/licenses/MIT).