Remove the word middleware (#1067)

* Rename middleware to plugin

first pass; mostly used 'sed', few spots where I manually changed
text.

This still builds a coredns binary.

* fmt error

* Rename AddMiddleware to AddPlugin

* Readd AddMiddleware to remain backwards compat

1 files changed, 0 insertions, 30 deletions

diff --git a/middleware/proxy/metrics.go b/middleware/proxy/metrics.go
deleted file mode 100644
index e9bb48d6f..000000000
--- a/middleware/proxy/metrics.go
+++ /dev/null
@@ -1,30 +0,0 @@
-package proxy
-
-import (
-	"sync"
-
-	"github.com/coredns/coredns/middleware"
-
-	"github.com/prometheus/client_golang/prometheus"
-)
-
-// Metrics the proxy middleware exports.
-var (
-	RequestDuration = prometheus.NewHistogramVec(prometheus.HistogramOpts{
-		Namespace: middleware.Namespace,
-		Subsystem: "proxy",
-		Name:      "request_duration_milliseconds",
-		Buckets:   append(prometheus.DefBuckets, []float64{50, 100, 200, 500, 1000, 2000, 3000, 4000, 5000, 10000}...),
-		Help:      "Histogram of the time (in milliseconds) each request took.",
-	}, []string{"proto", "proxy_proto", "from"})
-)
-
-// OnStartupMetrics sets up the metrics on startup. This is done for all proxy protocols.
-func OnStartupMetrics() error {
-	metricsOnce.Do(func() {
-		prometheus.MustRegister(RequestDuration)
-	})
-	return nil
-}
-
-var metricsOnce sync.Once