Implement implicit provisioning with config file; move cmd folder

README.md

@@ -64,12 +64,27 @@ Save this file as `config.json` in your working directory.
 
 ### Setting up storage on S3
 
-The easiest way to do this is to create an IAM user that has these two privileges:
+The easiest way to do this is to give an IAM user these two privileges (keep the credentials secret):
 
 - arn:aws:iam::aws:policy/**IAMFullAccess**
 - arn:aws:iam::aws:policy/**AmazonS3FullAccess**
 
-Keep its credentials secret, but export the following information to environment variables and run the provisioning command:
+##### Implicit Provisioning
+
+If you give these permissions to the same user as with the credentials in your JSON config above, then you can simply run:
+
+```bash
+$ checkup provision
+```
+
+and checkup will read the config file and provision S3 for you. If the user is different, you may want to use explicit provisioning instead.
+
+This command creates a new IAM user with read-only permission to S3 and also creates a new bucket just for your check files. The credentials of the new user are printed to your screen. **Make note of the Public Access Key ID and Public Access Key!** You won't be able to see them again.
+
+
+##### Explicit Provisioning
+
+If you do not prefer implicit provisioning using your checkup.json file, do this instead. Export the information to environment variables and run the provisioning command:
 
 ```bash
 $ export AWS_ACCESS_KEY_ID=...
@@ -78,8 +93,6 @@ $ export AWS_BUCKET_NAME=...
 $ checkup provision s3
 ```
 
-This command creates a new IAM user with read-only permission to S3 and also creates a new bucket just for your check files. The credentials of the new user are printed to your screen. **Make note of the Public Access Key ID and Public Access Key!** You won't be able to see them again.
-
 
 ### Setting up the status page
 

cmd/checkup/main.go

@@ -0,0 +1,7 @@
+package main
+
+import "github.com/sourcegraph/checkup/cmd"
+
+func main() {
+	cmd.Execute()
+}

cmd/provision.go

@@ -0,0 +1,114 @@
+package cmd
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strings"
+
+	"github.com/sourcegraph/checkup"
+	"github.com/spf13/cobra"
+)
+
+var provisionCmd = &cobra.Command{
+	Use:   "provision",
+	Short: "Provision a storage service",
+	Long: `Use the provision command to provision storage for your
+check files on any supported provider. Provisioning need 
+only be done once per status page. After provisioning,
+you will be provided some credentials; use those to
+configure your status page and/or checker. 
+
+By default, checkup.json will be loaded and used, if it 
+exists in the current working directory. Otherwise, you
+may provision your storage manually according to the
+instructions below.
+
+To do it manually, run 'checkup provision <provider>'
+with your provider of choice after setting the required
+environment variables.
+
+PROVIDERS
+
+s3
+    Create an IAM user with at least these two permissions:
+    
+       - arn:aws:iam::aws:policy/IAMFullAccess
+       - arn:aws:iam::aws:policy/AmazonS3FullAccess
+
+    Then set these env variables:
+
+       - AWS_ACCESS_KEY_ID=<AccessKeyID of user> 
+       - AWS_SECRET_ACCESS_KEY=<SecretAccessKey of user>
+       - AWS_BUCKET_NAME=<unique bucket name>`,
+	Run: func(cmd *cobra.Command, args []string) {
+		var prov checkup.Provisioner
+		var err error
+
+		switch len(args) {
+		case 0:
+			prov, err = provisionerConfig()
+		case 1:
+			prov, err = provisionerEnvVars(cmd, args)
+		default:
+			fmt.Println(cmd.Long)
+			os.Exit(1)
+		}
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		fmt.Println("One sec...")
+
+		info, err := prov.Provision()
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		fmt.Printf("Provision successful\n\n")
+		fmt.Printf("             User ID: %s\n", info.UserID)
+		fmt.Printf("            Username: %s\n", info.Username)
+		fmt.Printf("Public Access Key ID: %s\n", info.PublicAccessKeyID)
+		fmt.Printf("   Public Access Key: %s\n\n", info.PublicAccessKey)
+		fmt.Println(`IMPORTANT: Copy the Public Access Key ID and Public Access
+Key into the config.js file for your status page. You will
+not be shown these credentials again.`)
+	},
+}
+
+func provisionerConfig() (checkup.Provisioner, error) {
+	c := loadCheckup()
+	if c.Storage == nil {
+		return nil, fmt.Errorf("no storage configuration found")
+	}
+	prov, ok := c.Storage.(checkup.Provisioner)
+	if !ok {
+		return nil, fmt.Errorf("configured storage type does not have provisioning capabilities")
+	}
+	return prov, nil
+}
+
+func provisionerEnvVars(cmd *cobra.Command, args []string) (checkup.Provisioner, error) {
+	providerName := strings.ToLower(args[0])
+	switch providerName {
+	case "s3":
+		keyID := os.Getenv("AWS_ACCESS_KEY_ID")
+		secretKey := os.Getenv("AWS_SECRET_ACCESS_KEY")
+		bucket := os.Getenv("AWS_BUCKET_NAME")
+		if keyID == "" || secretKey == "" || bucket == "" {
+			fmt.Println(cmd.Long)
+			os.Exit(1)
+		}
+		return checkup.S3{
+			AccessKeyID:     keyID,
+			SecretAccessKey: secretKey,
+			Bucket:          bucket,
+		}, nil
+	default:
+		return nil, fmt.Errorf("unknown storage provider '%s'", providerName)
+	}
+}
+
+func init() {
+	RootCmd.AddCommand(provisionCmd)
+}

s3.go

@@ -70,6 +70,11 @@ func (s S3) Maintain() error {
 
 		var objsToDelete []*s3.ObjectIdentifier
 		for _, o := range listResp.Contents {
+			if o == nil || o.LastModified == nil {
+				continue
+			}
+			// TODO: This next line panicked once with nil ptr deref. Why?
+			// (at the time we did not have the if statement above checking for nils)
 			if time.Since(*o.LastModified) > s.CheckExpiry {
 				objsToDelete = append(objsToDelete, &s3.ObjectIdentifier{Key: o.Key})
 			}