Expose node exporter for scraping

bundles/uberspace-clerie-monitoring/files/prometheus-node-exporter-web-config.yml

@@ -0,0 +1,2 @@
+basic_auth_users:
+  monitor: "$2y$05$b4TibqWAj3MDv3g.SCaPZe9r6jV8Vowvn/CBZOdScwgkE7JcIuUfK"

bundles/uberspace-clerie-monitoring/files/prometheus-node-exporter.ini

@@ -1,6 +1,7 @@
 [program:prometheus-node-exporter]
 command=prometheus-node-exporter
     --web.listen-address 0.0.0.0:9100
+    --web.config.file=/home/{{ node.username }}/.config/prometheus-node-exporter/web-config.yml
     --collector.disable-defaults
     --collector.textfile
     --collector.textfile.directory=/home/{{ node.username }}/.local/state/prometheus-node-exporter/textfiles

bundles/uberspace-clerie-monitoring/items.py

@@ -22,6 +22,12 @@ files = uberspaceify.files({
             "svc_uberspace_supervisord:prometheus-node-exporter:update",
         ],
     },
+    f"/home/{node.username}/.config/prometheus-node-exporter/web-config.yml": {
+        "source": "prometheus-node-exporter-web-config.yml",
+        "triggers": [
+            "svc_uberspace_supervisord:prometheus-node-exporter:restart",
+        ],
+    },
 })
 
 actions["prometheus-node-exporter-exists"] = {
@@ -45,3 +51,9 @@ svc_uberspace_supervisord["prometheus-node-exporter"] = {
         f"file:/home/{node.username}/etc/services.d/prometheus-node-exporter.ini",
     ],
 }
+
+uberspace_web_backend["/.node-exporter"] = {
+    "backend": "http",
+    "port": 9100,
+    "remove_prefix": True,
+}

items/uberspace_web_backend.py

@@ -0,0 +1,138 @@
+from bundlewrap.exceptions import BundleError
+from bundlewrap.items import Item
+
+
+def backend_segments_to_dict(segments):
+    attributes = {}
+
+    name = segments[0].strip()
+
+    attributes["backend"] = segments[1].strip().rstrip(",")
+
+    attributes["port"] = None
+
+    if ":" in attributes["backend"]:
+        backend_segments = attributes["backend"].split(":")
+        attributes["backend"] = backend_segments[0]
+        attributes["port"] = int(backend_segments[1])
+
+    attributes["remove_prefix"] = None
+
+    flag = segments[2]
+    if flag == "--remove-prefix":
+        attributes["remove_prefix"] = True
+
+    return attributes
+
+def get_backend_config(node, name):
+    result = node.run("uberspace web backend list", may_fail=True)
+    backend_lines = result.stdout_text.splitlines()
+
+    for line in backend_lines:
+        segments = line.split("=>", 1)[0].strip().split(" ")
+        if segments[0] == name:
+            d = backend_segments_to_dict(segments)
+            return d
+
+def make_display_string(name, attributes):
+    backend_name = attributes.get("backend")
+    if attributes.get("backend") == "http":
+        backend_name += f":{attributes.get('port')}"
+
+    args = [ backend_name ]
+
+    if attributes["remove_prefix"]:
+        args.append("--remove-prefix")
+
+    arg_string = ", ".join(args)
+
+    return f"{name} {arg_string}"
+
+def make_option_string(name, attributes):
+    out = []
+
+    out.append(name)
+    out.append(f" --{attributes.get('backend')}")
+
+    if attributes.get("backend") == "http":
+        out.append("--port")
+        out.append(str(attributes.get('port')))
+
+    if attributes["remove_prefix"]:
+        out.append("--remove-prefix")
+
+    return " ".join(out)
+
+class UberspaceWebBackend(Item):
+    """
+    Manage uberspace web backends
+    """
+    BUNDLE_ATTRIBUTE_NAME = "uberspace_web_backend"
+    ITEM_ATTRIBUTES = {
+        "backend": "apache",
+        "port": None,
+        "remove_prefix": None,
+    }
+    ITEM_TYPE_NAME = "uberspace_web_backend"
+
+    def __repr__(self):
+        return f"<UberspaceWebBackend {make_display_string(self.name, self.attributes)}>"
+
+    def cdict(self):
+        cdict = {}
+        for option, value in self.attributes.items():
+            if value is not None:
+                cdict[option] = value
+        return cdict
+
+    def fix(self, status):
+        self.node.run(f"uberspace web backend set {make_option_string(self.name, self.attributes)}", may_fail=True)
+
+    def sdict(self):
+        return get_backend_config(self.node, self.name)
+
+    @classmethod
+    def validate_attributes(cls, bundle, item_id, attributes):
+
+        if attributes.get("backend") == "apache":
+            if attributes.get("port") is not None:
+                raise BundleError(_(
+                    "do not set 'port' while using 'apache' for 'backend' on {item} in bundle '{bundle}'"
+                ).format(
+                    item=item_id,
+                    bundle=bundle.name,
+                ))
+
+            if attributes.get("remove_prefix") is not None:
+                raise BundleError(_(
+                    "do not set 'port' while using 'apache' for 'backend' on {item} in bundle '{bundle}'"
+                ).format(
+                    item=item_id,
+                    bundle=bundle.name,
+                ))
+
+        elif attributes.get("backend") == "http":
+            if not isinstance(attributes.get("port"), int):
+                raise BundleError(_(
+                    "'port' required and needs to be numeric while using 'http' for 'backend' on {item} in bundle '{bundle}'"
+                ).format(
+                    item=item_id,
+                    bundle=bundle.name,
+                ))
+
+            if attributes.get("remove_prefix") not in [True, False, None]:
+                raise BundleError(_(
+                    "expected boolean for 'remove_prefix' on {item} in bundle '{bundle}'"
+                ).format(
+                    item=item_id,
+                    bundle=bundle.name,
+                ))
+
+        else:
+            raise BundleError(_(
+                "expected 'apache' or 'http' for 'backend' on {item} in bundle '{bundle}'"
+            ).format(
+                item=item_id,
+                bundle=bundle.name,
+            ))
+