From 91211036d84baa5e15286539ddadbe6b3d6e7b22 Mon Sep 17 00:00:00 2001
From: Timo Wilken
Date: Sun, 3 Dec 2023 21:48:06 +0100
Subject: Expose Grafana externally

---
 tw/services/grafana.scm | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

(limited to 'tw/services')

diff --git a/tw/services/grafana.scm b/tw/services/grafana.scm
index 6555ba62..a796ba19 100644
--- a/tw/services/grafana.scm
+++ b/tw/services/grafana.scm
@@ -6,22 +6,31 @@
   #:use-module (gnu services configuration)
   #:use-module (gnu services databases)
   #:use-module (gnu services shepherd)
+  #:use-module (guix records)
+  #:use-module (tw services web)
   #:export (grafana-service-type
             grafana-configuration))
 
 ;; TODO: Mimir for long-term Prometheus metrics storage?
 ;; TODO: Store Grafana data in Postgres instead of SQLite?
-;; TODO: Back up /var/lib/grafana, especially grafana.db
 
 (define %grafana-user "grafana")
 (define %grafana-uid 472)  ; to match container
 
-;; TODO: reverse proxy to make it accessible at http://vin.wg/grafana?
 (define-configuration/no-serialization grafana-configuration
+  ;; TODO: update to 10.2.2
+  ;; https://hub.docker.com/r/grafana/grafana-oss/tags
   (container (string "docker.io/grafana/grafana-oss:9.5.2") "Container image to run.")
+  (domain (string "localhost") "The external domain which will resolve to this
+Grafana instance.")
   (bind-address (string "0.0.0.0") "The host IP to bind to.")
   (host-port (integer 3000) "The port to bind to on the host.")
-  (data-path (string "/var/lib/grafana") "The path to store data in, on the host."))
+  (data-path (string "/var/lib/grafana") "The path to store data in, on the host.")
+  (metrics-credentials-file (string "/etc/grafana/metrics-credentials") "The
+file name containing the user name and password to use for basic
+authentication to Grafana's metrics endpoint.  These are specified as the
+GF_METRICS_BASIC_AUTH_USERNAME and GF_METRICS_BASIC_AUTH_PASSWORD environment
+variables."))
 
 (define (grafana-accounts config)
   (list (user-account
@@ -43,6 +52,7 @@
                    (list #$(file-append docker-cli "/bin/docker") "run" "--rm" "--network=host"
                          "--name" "grafana" "--user" '#$%grafana-user
                          "-v" '#$(format #f "~a:/var/lib/grafana" (grafana-configuration-data-path config))
+                         "--env-file" '#$(grafana-configuration-metrics-credentials-file config)
                          ;; https://grafana.com/docs/grafana/latest/setup-grafana/configure-docker/
                          "-e" "GF_SERVER_PROTOCOL=http"  ; use Wireguard for encryption
                          "-e" '#$(format #f "GF_SERVER_HTTP_ADDR=~a" (grafana-configuration-bind-address config))
@@ -58,11 +68,23 @@
                          '#$(grafana-configuration-container config))))
          (stop #~(make-kill-destructor)))))
 
+(define (grafana-reverse-proxy config)
+  (match-record config <grafana-configuration> (domain bind-address host-port)
+    (if (string=? domain "localhost") (list)
+        (list (https-reverse-proxy-configuration
+               (domains (list domain))
+               (destination-port host-port)
+               (destination-ip
+                (if (string=? bind-address "0.0.0.0")
+                    "127.0.0.1"
+                    bind-address)))))))
+
 (define grafana-service-type
   (service-type
    (name 'grafana)
    (extensions
     (list (service-extension shepherd-root-service-type grafana-shepherd-service)
-          (service-extension account-service-type grafana-accounts)))
+          (service-extension account-service-type grafana-accounts)
+          (service-extension https-reverse-proxy-service-type grafana-reverse-proxy)))
    (default-value (grafana-configuration))
    (description "Grafana server, running under Docker.")))
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