Improved hooks and scripts

* Invoke hooks before and after updating
* Scripts can now be run --before and --after

README.md

@@ -1,7 +1,18 @@
 # Fresh: Keeping your docker stacks up to date
 
 Fresh was written to scratch an itch. It works by querying the respective repositories
-returning
+for the various manifests in order to determine if the images have been changed. If so
+it can do a combination of things:
+
+- Set the exitcode to indicate the freshness, `0` means up-to-date and `1` outdated.
+- Pull the updated images with docker-compose, and optionally recreate the containers
+  with `docker-compose up`.
+- Run a script before and after updating, f.ex. to enable maintenance mode or update
+  permission on volumes.
+- Notify webhooks when updating. Currently only Slack and Mattermost are supported.
+
+Fresh is designed to be invoked using cron or systemd timers, and as such provides
+a light-weight easy-to-use alternative to more complex toolkits.
 
 ## Building
 
@@ -13,6 +24,8 @@ Build using NoccyLabs Pharlite:
 
 Download the latest version (or build it yourself) and move it into `/usr/bin`.
 
+Go grab it at [https://dev.noccylabs.info/noccy/fresh/releases](https://dev.noccylabs.info/noccy/fresh/releases)
+
 ## Usage
 
 To check for updates, pull updated images and recreate any containers defined in the
@@ -20,6 +33,15 @@ To check for updates, pull updated images and recreate any containers defined in
 
     $ fresh.phar 
 
+Specify a directory to chdir into; very useful with cron:
+
+    $ fresh.phar --dir /srv/docker/mystack
+
+To invoke scripts or webhooks:
+
+    $ fresh.phar --before scripts/sitedown.sh --after scripts/siteup.sh \
+        --slack https://my.slack.or/mattermost/webhook
+
 For all available options, use the `--help` flag.
 
 ## Known Issues
@@ -37,6 +59,8 @@ For all available options, use the `--help` flag.
 - **What are these hashes?** Fresh grabs the manifest for the image from the registry
   and proceeds to hash a concatenation of all the various build layer hashes. This
   should mean if the image is new but the layers are the same nothing will be updated.
+- **How do I notify a Mattermost webook?** Mattermost webhooks are compatible with
+  Slack webhooks, so simply use the `--slack` flag.
 
 ## Changes
 
@@ -54,3 +78,8 @@ For all available options, use the `--help` flag.
 - The `--image` option finally works.
 - Added a `--write-state`/`-w` option to write updated hashes to the state file.
 - Implemented `--config` and `--config-type`options.
+
+**0.1.3**
+
+- Added a `--before` script hook, to complement the `--after` hook.
+- Hooks now invoked both before and after deploy.

src/Refresher.php

@@ -30,7 +30,8 @@ class Refresher
         ],
         'Hooks' => [
             'slack' => [ null, 'slack:', "Notify a slack webhook when updating", "FRESH_SLACK" ],
-            'script' => [ null, 'after:', "Invoke script after updating", "FRESH_AFTER" ],
+            'script-after' => [ null, 'after:', "Invoke script after updating", "FRESH_AFTER" ],
+            'script-before' => [ null, 'before:', "Invoke script before updating", "FRESH_BEFORE" ],
         ],
         'Config' => [
             'config' => [ 'c:', 'config:', "Use custom configuration file", "FRESH_CONFIG" ],
@@ -175,9 +176,11 @@ class Refresher
             }
 
             if ($updated !== null) {
-                $this->callHooks($updated);
+                $this->callHooks($updated, 'before');
-                $this->doUpdate($updated);
+                $this->callScript('before');
-                $this->callScript();
+                $this->doUpdate();
+                $this->callHooks($updated, 'after');
+                $this->callScript('after');
             }
                 
             exit(($updated === null) ? 0 : 1);
@@ -362,13 +365,22 @@ class Refresher
         }
     }
 
-    private function callHooks(array $updated)
+    private function callHooks(array $updated, string $event)
     {
-        $images = [];
+        switch ($event) {
-        foreach ($updated as $u) {
+            case 'before':
-            $images[] = sprintf("%s/%s:%s", $u->ref->getRegistry(), $u->ref->getImage(), $u->ref->getTag());
+                $images = [];
+                foreach ($updated as $u) {
+                    $images[] = sprintf("%s/%s:%s", $u->ref->getRegistry(), $u->ref->getImage(), $u->ref->getTag());
+                }
+                $msg = "Deploying updated containers:\n* ".join("\n* ", $images);
+                break;
+            case 'after':
+                $msg = "Deploy complete";
+                break;
+            default:
+                return;
         }
-        $msg = "Deploying updated containers:\n* ".join("\n* ", $images);
 
         foreach ($this->hooks as $hook) {
             $hook->sendMessage($msg, []);
@@ -376,9 +388,9 @@ class Refresher
 
     }
 
-    private function callScript()
+    private function callScript(string $event)
     {
-        $script = $this->options['script'];
+        $script = $this->options["script-{$event}"] ?? null;
         if ($script) {
             $this->exec($script);
         }