OpenTSDB output plugin broken when host is given without scheme

[alfredkrohmer]

In this code line, url.Parse is used to parse the given host string. If this string does not contain a scheme (e.g. google.com instead of tcp://google.com), u.Host is an empty string and the connect fails.

Bug report

Relevant telegraf.conf:

[[outputs.opentsdb]]
 prefix = "telegraf."
 host = "google.com"
 port = 4242

System info:

• Telegraf version 1.1.2

Steps to reproduce:

Provide a host without a scheme to the OpenTSDB output plugin.

Expected behavior:

The plugin should be able connect to the host.

Actual behavior:

The connection fails with: Failed to connect to output opentsdb, retrying in 15s, error was 'OpenTSDB: Telnet connect fail'

[phemmer]

On the larger scope of the issue, it would be really nice if telegraf were consistent in its naming of such parameters. Right now it's all over the place. Some parameters are called "url" and take a host, some parameters are called "host" and take a url. Others are called "address" and take a url, or host, etc.
Then you have other examples like this one, where they take a url, but parameters that are able to be placed in the url are instead configured separately (e.g. port).

[sparrc]

@phemmer that would be better, but would also be a breaking change at this point :(

[alfredkrohmer]

Also, the error message is not really helpful. Maybe the error returned from DialTCP can be returned instead of that generic error message?

[sparrc]

I will add the error message in as well