split image tag

closes #20

---------

Co-authored-by: Danny Groenewegen <danny@ecommons.space>
Reviewed-on: #21
Reviewed-by: ammaratef45 <ammaratef45@proton.me>
Reviewed-by: Danny Groenewegen <247+dannygroenewegen@noreply.git.coopcloud.tech>
Co-authored-by: f <f@sutty.nl>

config.alloy.tmpl

@@ -48,7 +48,32 @@ prometheus.scrape "default" {
     prometheus.exporter.cadvisor.docker.targets,
   )
 
+  forward_to = [prometheus.relabel.container_meta.receiver]
+}
+
+prometheus.relabel "container_meta" {
   forward_to = [prometheus.remote_write.prometheus.receiver]
+
+  // remove sha tail: nginx:1.31.1@sha256:608a... -> nginx:1.31.1
+  rule {
+    source_labels = ["image"]
+    regex         = "([^@]+)@sha256:.*"
+    target_label  = "image"
+    replacement   = "$1"
+  }
+  // split image in name and tag
+  rule {
+    source_labels = ["image"]
+    regex         = "(.+):[^:/]+"
+    target_label  = "image_name"
+    replacement   = "$1"
+  }
+  rule {
+    source_labels = ["image"]
+    regex         = ".+:([^:/]+)"
+    target_label  = "image_tag"
+    replacement   = "$1"
+  }
 }
 
 prometheus.remote_write "prometheus" {