Added migrating eventline to nixos blog article

content/blog/nix/migrating-eventline.md

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+---
+title: Migrating eventline to nixos
+description: How I migrated my eventline installation to nixos
+date: 2024-03-22
+tags:
+- eventline
+- nix
+---
+
+## Introduction
+
+I am migrating several services from a FreeBSD server to a nixos server. Here is how I performed the operation for [eventline](https://www.exograd.com/products/eventline/).
+
+## Eventline on nixos
+
+Eventline is not packaged on nixos, so that might be a good project to try and tackle in the near future. In the meantime I used the container image.
+
+Here is the module I wrote to deploy an eventline container, configure postgresql and borg backups:
+```nix
+{ config, lib, pkgs, ... }:
+{
+    imports = [
+      ../../lib/postgresql.nix
+    ];
+    environment.etc = {
+        "borg-eventline-db.key" = {
+            mode = "0400";
+            source = ./borg-db.key;
+        };
+        "eventline.yaml" = {
+            mode = "0400";
+            source = ./eventline.yaml;
+            uid = 1000;
+        };
+        "eventline-entrypoint" = {
+            mode = "0500";
+            source = ./eventline-entrypoint;
+            uid = 1000;
+        };
+    };
+    services = {
+        borgbackup.jobs = let defaults = {
+            compression = "auto,zstd";
+            doInit = true;
+            encryption.mode = "none";
+            prune.keep = {
+                daily = 14;
+                weekly = 4;
+                monthly = 3;
+            };
+            startAt = "daily";
+        }; in {
+            "eventline-db" = defaults // {
+                environment.BORG_RSH = "ssh -i /etc/borg-eventline-db.key";
+                paths = "/tmp/eventline.sql";
+                postHook = "rm -f /tmp/eventline.sql";
+                preHook = ''rm -f /tmp/eventline.sql; /run/current-system/sw/bin/pg_dump -h localhost -U eventline -d eventline > /tmp/eventline.sql'';
+                repo = "ssh://borg@gcp.adyxax.org/srv/borg/eventline-db";
+            };
+        };
+        nginx.virtualHosts = let
+            headersSecure = ''
+                # A+ on https://securityheaders.io/
+                add_header X-Frame-Options deny;
+                add_header X-XSS-Protection "1; mode=block";
+                add_header X-Content-Type-Options nosniff;
+                add_header Referrer-Policy strict-origin;
+                add_header Cache-Control no-transform;
+                add_header Content-Security-Policy "script-src 'self'";
+                add_header Permissions-Policy "accelerometer=(), camera=(), geolocation=(), gyroscope=(), magnetometer=(), microphone=(), payment=(), usb=()";
+                # 6 months HSTS pinning
+                add_header Strict-Transport-Security max-age=16000000;
+            '';
+            headersStatic = headersSecure + ''
+                add_header Cache-Control "public, max-age=31536000, immutable";
+            '';
+        in {
+            "eventline.adyxax.org" = {
+                forceSSL = true;
+                locations = {
+                    "/" = {
+                        extraConfig = headersSecure;
+                        proxyPass = "http://127.0.0.1:8087";
+                    };
+                };
+                sslCertificate = "/etc/nginx/adyxax.org.crt";
+                sslCertificateKey = "/etc/nginx/adyxax.org.key";
+            };
+            "eventline-api.adyxax.org" = {
+                locations = {
+                    "/" = {
+                        extraConfig = headersSecure;
+                        proxyPass = "http://127.0.0.1:8085";
+                    };
+                };
+                onlySSL = true;
+                sslCertificate = "/etc/nginx/adyxax.org.crt";
+                sslCertificateKey = "/etc/nginx/adyxax.org.key";
+            };
+        };
+        postgresql = {
+            ensureDatabases = ["eventline"];
+            ensureUsers = [{
+                name = "eventline";
+                ensureDBOwnership = true;
+            }];
+        };
+    };
+    virtualisation.oci-containers.containers = {
+        eventline = {
+            image = "exograd/eventline:1.1.0";
+            ports = [
+                "127.0.0.1:8085:8085" # api
+                "127.0.0.1:8087:8087" # web
+            ];
+            user = "root:root";
+            volumes = [
+                "/etc/eventline.yaml:/etc/eventline/eventline.yaml:ro"
+                "/etc/eventline-entrypoint:/usr/bin/entrypoint:ro"
+            ];
+        };
+    };
+}
+```
+
+## Dependencies
+
+The dependencies are mostly the same as in [my article about vaultwarden migration]({{< ref "migrating-vaultwarden.md" >}}#dependencies). One key difference is that there are two nginx virtual hosts and a bunch of files I need for eventline.
+
+## Migration process
+
+The first step is obviously to deploy this new configuration to the server, then I need to login and manually restore the backups.
+```sh
+make run host=dalinar.adyxax.org
+```
+
+The container will be failing because no password is set on the database user yet, so I stop it:
+```sh
+systemctl stop podman-eventline
+```
+
+There is only one backup job for eventline and it holds a dump of the database:
+```sh
+export BORG_RSH="ssh -i /etc/borg-eventline-db.key"
+borg list ssh://borg@gcp.adyxax.org/srv/borg/eventline-db
+borg extract ssh://borg@gcp.adyxax.org/srv/borg/eventline-db::dalinar-eventline-db-2023-11-20T00:00:01
+psql -h localhost -U postgres -d eventline
+```
+
+Restoring the data itself is done with the psql shell:
+```sql
+ALTER USER eventline WITH PASSWORD 'XXXXXX';
+\i tmp/eventline.sql
+```
+
+Afterwards I clean up the database dump and restart eventline:
+```sh
+rm -rf tmp/
+systemctl start podman-eventline
+```
+
+To wrap this up I migrate the DNS records to the new host, update my monitoring system and clean up the jail on the FreeBSD server.
+
+## Conclusion
+
+I did all this in november, I still have quite the backlog of articles to write about nix!