add first steps for ghettoscale

3 files changed, 144 insertions, 0 deletions

diff --git a/cmd/ghettoscale/main.go b/cmd/ghettoscale/main.go
new file mode 100644
index 0000000..8ad78c6
--- /dev/null
+++ b/cmd/ghettoscale/main.go
@@ -0,0 +1,42 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"net/url"
+	"os"
+	"time"
+
+	"github.com/Xe/ln"
+	_ "github.com/joho/godotenv/autoload"
+)
+
+var (
+	every = flag.Duration("every", 10*time.Minute, "how often this binary is being run")
+	do    = flag.Int("do", 1, "do this number of scale checks, staggered by -every")
+)
+
+func main() {
+	flag.Parse()
+	ctx := context.Background()
+	ctx = ln.WithF(ctx, ln.F{"at": "main"})
+
+	pool, err := NewRedisPoolFromURL(os.Getenv("REDIS_URL"))
+	if err != nil {
+		ln.FatalErr(ctx, err)
+	}
+	_ = pool
+
+	for _, a := range flag.Args() {
+		ln.Log(ctx, ln.F{"url": a})
+		u, err := url.Parse(a)
+		if err != nil {
+			ln.FatalErr(ctx, err)
+		}
+
+		err = Check(ctx, u)
+		if err != nil {
+			ln.FatalErr(ctx, err)
+		}
+	}
+}
diff --git a/cmd/ghettoscale/redis.go b/cmd/ghettoscale/redis.go
new file mode 100644
index 0000000..94375c0
--- /dev/null
+++ b/cmd/ghettoscale/redis.go
@@ -0,0 +1,27 @@
+package main
+
+import (
+	"time"
+
+	"github.com/garyburd/redigo/redis"
+)
+
+// NewRedisPoolFromURL returns a new *redigo/redis.Pool configured for th1e supplied url
+// The url can include a password in the standard form and if so is used to AUTH against
+// the redis server.
+func NewRedisPoolFromURL(url string) (*redis.Pool, error) {
+	return &redis.Pool{
+		MaxIdle:     3,
+		IdleTimeout: 240 * time.Second,
+		Dial: func() (redis.Conn, error) {
+			return redis.DialURL(url)
+		},
+		TestOnBorrow: func(c redis.Conn, t time.Time) error {
+			if time.Since(t) < time.Minute {
+				return nil
+			}
+			_, err := c.Do("PING")
+			return err
+		},
+	}, nil
+}
diff --git a/cmd/ghettoscale/scale.go b/cmd/ghettoscale/scale.go
new file mode 100644
index 0000000..fa503f8
--- /dev/null
+++ b/cmd/ghettoscale/scale.go
@@ -0,0 +1,75 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+)
+
+// State is the state of the ghetto autoscaler.
+type State int
+
+/*
+States that this can be in
+
+    digraph G {
+	ok [label="OK"]
+	scaling_up [label="Scaling Up"]
+	scaling_down [label="Scaling Down"]
+	max_scale [label="Max Scale"]
+
+	init -> ok [label="test passes"]
+	init -> scaling_up [label="test fails"]
+	ok -> scaling_up [label="test fails"]
+	scaling_up -> scaling_up [label="test fails"]
+	scaling_up -> max_scale [label="test fails"]
+	scaling_up -> ok [label="test passes"]
+	scaling_down -> ok [label="minimum\nscale"]
+	ok -> scaling_down [label="test has\npassed\nn times"]
+	scaling_down -> scaling_down [label="test passes"]
+	max_scale -> scaling_down [label="test passes"]
+	max_scale -> ok [label="test passes"]
+    }
+
+This is the overall state machine for the autoscaler.
+*/
+const (
+	Init State = iota
+	OK
+	ScalingUp
+	MaxScale
+	ScalingDown
+)
+
+func Check(ctx context.Context, u *url.URL) error {
+	switch u.Scheme {
+	case "heroku":
+		return CheckHeroku(ctx, u)
+	}
+
+	return fmt.Errorf("no such scheme for %s", u.Scheme)
+}
+
+func CheckHeroku(ctx context.Context, u *url.URL) error {
+	// q := u.Query()
+	var err error
+
+	// heroku://printerfacts/web?kind=lang&metric=g:go.routines_max&min=1&max=3&stagger=1&mode=threshold&threshold=500
+	// appID := u.Host
+	// processType := u.Path[1:]
+	// kind := q.Get("kind")
+	// metric := q.Get("metric")
+	// min := q.Get("min")
+	// max := q.Get("max")
+	// stagger := q.Get("stagger")
+	// mode := q.Get("mode")
+
+	// get redis connection
+	//  check if app:process type is currently staggered in redis
+	//   if so decrement stagger counter in redis and exit
+	// fetch metrics data from metrics-api
+	// fetch current number of dynos for this app id and process type
+	// fetch state of the
+
+	return err
+}