Replace telegraf with node exporter

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

packages/docker/prometheus-podman-exporter/default.nix

@@ -0,0 +1,40 @@
+{
+  pkgs,
+  inputs,
+  system,
+  ...
+}:
+let
+  selfPkgs = inputs.self.packages.${system};
+
+  entrypoint = pkgs.writeTextFile {
+    name = "entrypoint";
+    executable = true;
+    destination = "/bin/entrypoint";
+    text = builtins.readFile ./entrypoint.sh;
+  };
+in
+pkgs.dockerTools.buildImage {
+  name = "prometheus-podman-exporter";
+  fromImage = import ../base { inherit pkgs; };
+
+  copyToRoot = pkgs.buildEnv {
+    name = "root";
+    paths = [
+      entrypoint
+      selfPkgs.prometheus-podman-exporter
+    ];
+    pathsToLink = [ "/bin" ];
+  };
+
+  runAsRoot = ''
+    ${pkgs.dockerTools.shadowSetup}
+  '';
+
+  config = {
+    Entrypoint = [ "/bin/entrypoint" ];
+    ExposedPorts = {
+      "9882/tcp" = { };
+    };
+  };
+}

packages/docker/prometheus-podman-exporter/entrypoint.sh

@@ -0,0 +1,23 @@
+#!/bin/sh
+
+set -o errexit
+set -o nounset
+
+mkdir -p /tmp
+LOG_PIPE="$(mktemp -u)"
+mkfifo "$LOG_PIPE"
+
+(
+  while IFS= read -r line; do
+    if echo "$line" | grep -qEi "WARN|ERROR|FATAL"; then
+      echo "$line" >&2
+    else
+      echo "$line"
+    fi
+  done < "$LOG_PIPE"
+) &
+LOG_PID=$!
+
+trap 'kill $LOG_PID' EXIT
+
+exec /bin/prometheus-podman-exporter "$@" > "$LOG_PIPE" 2>&1