Fix parse monitor URL

[lifenod]

url.Parse will fail when to parse Lacoste3 INFLUXDB_URL, error is net/url: invalid userinfo.

Because Lacoste3 userinfo contain invalid character ], see detail https://github.com/golang/go/blob/6a64efc25004175e198e75191e215a7b1a08a2fa/src/net/url/url.go#L1115.

I write a regexp to capture config.

[junhuif]

It seems it's quite common to use url.Parse to parse the URL configuration, for example

• lib/pq
• jackc/pgx
• go-goracle/goracle

So, I think it's more useful to change that password instead of modifying the code.

[lifenod]

Let's change back, and abstract a parseConfig function.

[bodhi]

It seems it's quite common to use url.Parse to parse the URL configuration

Agree with this.

Because Lacoste3 userinfo contain invalid character ]

So if we define the input as a URL, then ] should be escaped, as it says in the comment above the linked function (and in the RFC):

// validUserinfo reports whether s is a valid userinfo string per RFC 3986
// Section 3.2.1:
//     userinfo    = *( unreserved / pct-encoded / sub-delims / ":" )
//     unreserved  = ALPHA / DIGIT / "-" / "." / "_" / "~"
//     sub-delims  = "!" / "$" / "&" / "'" / "(" / ")"
//                   / "*" / "+" / "," / ";" / "="

so ] should be %5D, and it's decoded by url.Userinfo: https://play.golang.org/p/7D8BCvdizYZ

package main

import (
	"fmt"
	"net/url"
)

func main() {
	u, e := url.Parse("http://hello%5d:password@example.com")
	fmt.Println(u, e)
	fmt.Println(u.User.Username())
}

output:

http://hello%5D:password@example.com <nil>
hello]

[lifenod]

Let's escape the URL.