readme update, added goreleaser

.goreleaser.yml

@@ -0,0 +1,30 @@
+before:
+  hooks:
+    # You may remove this if you don't use go modules.
+    - go mod download
+    # you may remove this if you don't need go generate
+    - go generate ./...
+builds:
+- env:
+  - CGO_ENABLED=0
+  goarch:
+    - amd64
+    - arm
+    - arm64
+  goos:
+    - linux
+    - windows
+    - darwin
+
+project_name: openhab_exporter
+
+checksum:
+  name_template: 'checksums.txt'
+snapshot:
+  name_template: "{{ .Tag }}"
+changelog:
+  sort: asc
+  filters:
+    exclude:
+    - '^docs:'
+    - '^test:'

README.md

@@ -4,4 +4,44 @@ Implementation in Go ready to export [Openhab](https://www.openhab.org/) metrics
 
 Exported are metrics from items types: `Number`, `Dimmer`, `Switch`,`Contact`.
 
-## Installation
+## Example usage
+Only one parameter is required `--apiurl`, which should be address of your Openhab installation.
+```
+-> % ./openhab_exporter --apiurl=http://192.168.0.116:8080
+level=info ts=2020-07-08T15:34:45.713Z caller=main.go:42 msg="Starting openhab_exporter" version="(version=, branch=, revision=)"
+level=info ts=2020-07-08T15:34:45.713Z caller=main.go:43 build_context="(go=go1.14.4, user=, date=)"
+level=info ts=2020-07-08T15:34:45.879Z caller=main.go:47 msg="Listening on address" address=:9266
+```
+
+Open new terminal window and check results:
+```
+-> % curl -v localhost:9266/metrics
+*   Trying 127.0.0.1...
+* TCP_NODELAY set
+* Connected to localhost (127.0.0.1) port 9266 (#0)
+> GET /metrics HTTP/1.1
+> Host: localhost:9266
+> User-Agent: curl/7.64.1
+> Accept: */*
+>
+< HTTP/1.1 200 OK
+< Content-Type: text/plain; version=0.0.4; charset=utf-8
+< Date: Wed, 08 Jul 2020 15:35:24 GMT
+< Transfer-Encoding: chunked
+<
+# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.
+# TYPE go_gc_duration_seconds summary
+go_gc_duration_seconds{quantile="0"} 0
+go_gc_duration_seconds{quantile="0.25"} 0
+
+...
+
+# HELP openhab_item_state_current Openhab items current state
+# TYPE openhab_item_state_current gauge
+openhab_item_state_current{groupnames="",item="ActionsPower",label="Power on/off",tags="",type="Switch"} 0
+openhab_item_state_current{groupnames="",item="AlarmAlert",label="Alarm alert",tags="",type="Switch"} 0
+openhab_item_state_current{groupnames="",item="Gateway_AddDevice",label="",tags="",type="Switch"} 0
+
+...
+
+```