Migrate to flatcar linux from coreos (#1836)

* Migrate to flatcar linux from coreos

* Remove errors package references - stick with fmt.Errorf
Reduce nesting in GetAMI function

Author: davidmccormick

cmd/init.go

@@ -6,8 +6,8 @@ import (
 
 	"github.com/kubernetes-incubator/kube-aws/builtin"
 	"github.com/kubernetes-incubator/kube-aws/core/root/config"
-	"github.com/kubernetes-incubator/kube-aws/coreos/amiregistry"
 	"github.com/kubernetes-incubator/kube-aws/filegen"
+	"github.com/kubernetes-incubator/kube-aws/flatcar/amiregistry"
 	"github.com/kubernetes-incubator/kube-aws/logger"
 	"github.com/spf13/cobra"
 )

coreos/amiregistry/amiregistry.go

@@ -0,0 +1,50 @@
+package amiregistry
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+func GetAMI(region, channel string) (string, error) {
+
+	amis, err := GetAMIData(channel)
+
+	if err != nil {
+		return "", fmt.Errorf("uanble to fetch AMI for channel \"%s\": %v", channel, err)
+	}
+
+	for _, v := range amis {
+		if v["name"] != region {
+			continue
+		}
+		if hvm, ok := v["hvm"]; ok {
+			return hvm, nil
+		} else {
+			break
+		}
+	}
+
+	return "", fmt.Errorf("could not find \"hvm\" image for region \"%s\" in flatcar channel \"%s\"", region, channel)
+}
+
+func GetAMIData(channel string) ([]map[string]string, error) {
+	url := fmt.Sprintf("https://%s.release.flatcar-linux.net/amd64-usr/current/flatcar_production_ami_all.json", channel)
+	r, err := newHttp().Get(url)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get AMI data from url \"%s\": %v", channel, err)
+	}
+
+	if r.StatusCode != 200 {
+		return nil, fmt.Errorf("failed to get AMI data from url \"%s\": invalid status code: %d", url, r.StatusCode)
+	}
+
+	output := map[string][]map[string]string{}
+
+	err = json.NewDecoder(r.Body).Decode(&output)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse AMI data from url \"%s\": %v", url, err)
+	}
+	r.Body.Close()
+
+	return output["amis"], nil
+}

flatcar/amiregistry/amiregistry.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/kubernetes-incubator/kube-aws/coreos/amiregistry"
+	"github.com/kubernetes-incubator/kube-aws/flatcar/amiregistry"
 	"github.com/kubernetes-incubator/kube-aws/pkg/api"
 	"github.com/pkg/errors"
 )

coreos/amiregistry/reliable_http.go renamed to flatcar/amiregistry/reliable_http.go

@@ -3,7 +3,7 @@ package model
 import (
 	"fmt"
 
-	"github.com/kubernetes-incubator/kube-aws/coreos/amiregistry"
+	"github.com/kubernetes-incubator/kube-aws/flatcar/amiregistry"
 	"github.com/kubernetes-incubator/kube-aws/logger"
 	"github.com/kubernetes-incubator/kube-aws/pkg/api"
 	"github.com/pkg/errors"