system: add pipe-to-loki helper script

Adds a system-wide script for sending command output or interactive
sessions to Loki for easy sharing with Claude.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

system/default.nix

@@ -9,6 +9,7 @@
     ./motd.nix
     ./packages.nix
     ./nix.nix
+    ./pipe-to-loki.nix
     ./root-user.nix
     ./pki/root-ca.nix
     ./sshd.nix

system/pipe-to-loki.nix

@@ -0,0 +1,140 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}:
+let
+  pipe-to-loki = pkgs.writeShellApplication {
+    name = "pipe-to-loki";
+    runtimeInputs = with pkgs; [
+      curl
+      jq
+      util-linux
+      coreutils
+    ];
+    text = ''
+      set -euo pipefail
+
+      LOKI_URL="http://monitoring01.home.2rjus.net:3100/loki/api/v1/push"
+      HOSTNAME=$(hostname)
+      SESSION_ID=""
+      RECORD_MODE=false
+
+      usage() {
+        echo "Usage: pipe-to-loki [--id ID] [--record]"
+        echo ""
+        echo "Send command output or interactive sessions to Loki."
+        echo ""
+        echo "Options:"
+        echo "  --id ID      Set custom session ID (default: auto-generated)"
+        echo "  --record     Start interactive recording session"
+        echo ""
+        echo "Examples:"
+        echo "  command | pipe-to-loki           # Pipe command output"
+        echo "  command | pipe-to-loki --id foo  # Pipe with custom ID"
+        echo "  pipe-to-loki --record            # Start recording session"
+        exit 1
+      }
+
+      generate_id() {
+        local random_chars
+        random_chars=$(head -c 2 /dev/urandom | od -An -tx1 | tr -d ' \n')
+        echo "''${HOSTNAME}-$(date +%s)-''${random_chars}"
+      }
+
+      send_to_loki() {
+        local content="$1"
+        local type="$2"
+        local timestamp_ns
+        timestamp_ns=$(date +%s%N)
+
+        local payload
+        payload=$(jq -n \
+          --arg job "pipe-to-loki" \
+          --arg host "$HOSTNAME" \
+          --arg type "$type" \
+          --arg id "$SESSION_ID" \
+          --arg ts "$timestamp_ns" \
+          --arg content "$content" \
+          '{
+            streams: [{
+              stream: {
+                job: $job,
+                host: $host,
+                type: $type,
+                id: $id
+              },
+              values: [[$ts, $content]]
+            }]
+          }')
+
+        if curl -s -X POST "$LOKI_URL" \
+          -H "Content-Type: application/json" \
+          -d "$payload" > /dev/null; then
+          return 0
+        else
+          echo "Error: Failed to send to Loki" >&2
+          return 1
+        fi
+      }
+
+      # Parse arguments
+      while [[ $# -gt 0 ]]; do
+        case $1 in
+          --id)
+            SESSION_ID="$2"
+            shift 2
+            ;;
+          --record)
+            RECORD_MODE=true
+            shift
+            ;;
+          --help|-h)
+            usage
+            ;;
+          *)
+            echo "Unknown option: $1" >&2
+            usage
+            ;;
+        esac
+      done
+
+      # Generate ID if not provided
+      if [[ -z "$SESSION_ID" ]]; then
+        SESSION_ID=$(generate_id)
+      fi
+
+      if $RECORD_MODE; then
+        # Session recording mode
+        SCRIPT_FILE=$(mktemp)
+        trap 'rm -f "$SCRIPT_FILE"' EXIT
+
+        echo "Recording session $SESSION_ID... (exit to send)"
+
+        # Use script to record the session
+        script -q "$SCRIPT_FILE"
+
+        # Read the transcript and send to Loki
+        content=$(cat "$SCRIPT_FILE")
+        if send_to_loki "$content" "session"; then
+          echo "Session $SESSION_ID sent to Loki"
+        fi
+      else
+        # Pipe mode - read from stdin
+        if [[ -t 0 ]]; then
+          echo "Error: No input provided. Pipe a command or use --record for interactive mode." >&2
+          exit 1
+        fi
+
+        content=$(cat)
+        if send_to_loki "$content" "command"; then
+          echo "Sent to Loki with id: $SESSION_ID"
+        fi
+      fi
+    '';
+  };
+in
+{
+  environment.systemPackages = [ pipe-to-loki ];
+}