Add support for "last update" metrics (#12)

* Add support for "last update" metrics

* Update exported metrics

README.md

@@ -16,6 +16,15 @@ Additionally, `pkg_reboot_required` is exported to indicate that an reboot is ne
 # HELP pkg_reboot_required Node Requires an Reboot
 # TYPE pkg_reboot_required gauge
 pkg_reboot_required 1.0
+# HELP pkg_update_start_time timestamp of last apt update start
+# TYPE pkg_update_start_time gauge
+pkg_update_start_time 1.641382890503045e+09
+# HELP pkg_update_end_time Timestamp of last apt update finish
+# TYPE pkg_update_end_time gauge
+pkg_update_end_time 1.641382892755024e+09
+# HELP pkg_update_time_available Availability of the apt update timestamp
+# TYPE pkg_update_time_available gauge
+pkg_update_time_available 1.0
 # HELP pkg_installed Installed packages per origin
 # TYPE pkg_installed gauge
 pkg_installed{archive="focal-updates",component="main",label="Ubuntu",origin="Ubuntu",site="ftp.fau.de",trusted="True"} 672.0
@@ -58,12 +67,16 @@ The exporter needs to be executed with appropriate privileges, which are not nec
 
 An example configuration will be provided in this repository in the future.
 
+### apt hook
+To enable monitoring for apt update calls, place the file under `docs/00-pve-exporter` in `/etc/apt/apt.conf.d` on your system. It will place files under `/tmp`, you can see the success of monitoring the apt update timestamps if the following metric is 1: `pkg_update_time_available 1.0`
+
+Please not that the presence of an timestamp does not mean that all repositories were updated without issues.
+
 ## Alerting
 
 Example alerting rules will be provided in the future.
 
 ## Roadmap
 
 - Support for other pkg managers
-- Timestamp Support ("Last List/Cache Update")
 - Deployment as dpkg-Packet

docs/00-pve-exporter

@@ -0,0 +1,4 @@
+# this is the apt hook provided by the pve exporter. This file shall be placed under /etc/apt/apt.conf.d
+APT::Update::Pre-Invoke {"touch /tmp/pkg-exporter-apt-update-pre"; };
+APT::Update::Post-Invoke {"touch /tmp/pkg-exporter-apt-update-post"; };
+APT::Periodic::Update-Package-Lists "1";

src/pkg_exporter/pkgmanager/apt.py

@@ -1,5 +1,6 @@
 import apt
 import apt.progress
+from pathlib import Path
 
 
 class AptPkgManager:
@@ -14,6 +15,11 @@ def __init__(self):
         self.metricDict["broken"] = \
             {"description": "Broken packages per origin"}
         self.metricsByOrigin = {}
+        self.metaMetrics = {}
+        self.metaMetrics["update_time_available"] = 0
+        self.metaMetrics["update_start_time"] = 0
+        self.metaMetrics["update_end_time"] = 0
+
         self.cache = apt.Cache()
         self.cache.open(None)
 
@@ -25,6 +31,16 @@ def labelValues(self, origin):
     def getMetricDict(self):
         return self.metricDict
 
+    def getMetaMetricDict(self):
+        updateMetrics = {}
+        updateMetrics["update_start_time"] = \
+            {"description": "timestamp of last apt update start"}
+        updateMetrics["update_end_time"] = \
+            {"description": "Timestamp of last apt update finish"}
+        updateMetrics["update_time_available"] = \
+            {"description": "Availability of the apt update timestamp"}
+        return updateMetrics
+
     def getLabelNames(self):
         labelNames = ["archive", "component", "label", "origin",
                       "site", "trusted"]
@@ -54,6 +70,15 @@ def query(self):
                 self.metricsByOrigin[key]["auto_removable"] += 1
             if selected_package.is_now_broken:
                 self.metricsByOrigin[key]["broken"] += 1
+        # apt update time
+        preUpdatePath = Path("/tmp/pkg-exporter-apt-update-pre")
+        postUpdatePath = Path("/tmp/pkg-exporter-apt-update-post")
+        if preUpdatePath.is_file() and postUpdatePath.is_file():
+            self.metaMetrics["update_time_available"] = 1
+            self.metaMetrics["update_start_time"] = \
+                preUpdatePath.stat().st_mtime
+            self.metaMetrics["update_end_time"] = \
+                postUpdatePath.stat().st_mtime
 
     def getMetricValue(self, name):
         metricValue = []
@@ -66,3 +91,6 @@ def getMetricValue(self, name):
                 continue
             metricValue.append(v)
         return metricValue
+
+    def getMetaValue(self, name):
+        return self.metaMetrics[name]

src/pkg_exporter/textfile.py

@@ -15,6 +15,8 @@ def main():
     # initially, check which metrics and labels are available
     metrics = pkgmanager.getMetricDict()
     labels = pkgmanager.getLabelNames()
+    gauges = {}
+    meta_gauges = {}
 
     # also add reboot metrics
     rebootmanager = reboot.RebootManager()
@@ -23,8 +25,15 @@ def main():
                 [], registry=registry
                 )
 
+    # add update statistics
+    meta_metric = pkgmanager.getMetaMetricDict()
+    for key, value in meta_metric.items():
+        meta_gauges[key] = Gauge(
+                f'pkg_{key}', value["description"],
+                registry=registry
+                )
+
     # Create all the gauge metrics
-    gauges = {}
     for key, value in metrics.items():
         gauges[key] = Gauge(
                 f'pkg_{key}', value["description"],
@@ -40,6 +49,9 @@ def main():
         for m in metricList:
             gauge.labels(*m["label"]).set(m["value"])
 
+    for name, gauge in meta_gauges.items():
+        gauge.set(pkgmanager.getMetaValue(name))
+
     rebootmanager.query()
     reboot_gauge.set(rebootmanager.getMetricValue())