listen_ipv6 config option is removed and we now
listen on both ipv4 and ipv6 addresses.
HTTP keepalive is enabled and set to 70s by default.

With uhttpd-mod-lua there is a small change in behavior,
all code is loaded/parsed/executed once on startup as before,
but now each request is executed in his own fork, so we can't
keep a state between requests.

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>
(cherry picked from commit 60460f0046)

Add my email address to the copyright for the file.

Signed-off-by: Kevin Lyda <kevin@lyda.ie>

Signed-off-by: Leonid Evdokimov <leon@darkk.net.ru>

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

As prometheus-node-exporter-lua is a reimplementation of node_exporter,
I'm using "collector" instead of "scraper" and renaming some collectors

put each collector in a separate file

report collector success/failure and duration per scrape
(follow https://github.com/prometheus/node_exporter/pull/516)

allow to filter collectors using "collect[]" params
(see https://github.com/prometheus/node_exporter#filtering-enabled-collectors)

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

On my bullet m2, scrape duration goes from between 0.2 and 0.5 to a stable 0.025
We also don't depend on luci anymore

This remove wifi_network_up metric, but this metric was buggy
wifi_network_up{ifname="wlan0-1",ssid="test1",channel="11",mode="Master",bssid="12:34:56:78:9A:BC",country="FR",frequency="2.462"} 1
wifi_network_up{ifname="radio0.network2",ssid="test1",channel="11",mode="Master",country="US",frequency="2.462"} 0

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

Testing on a bullet m2, uname collector was taking on average 0.12
it now takes 0.0007

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

also reduce calls to output()

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

Signed-off-by: Christian Simon <simon@swine.de>