Merge pull request 'user: add gitea-vault-admin site-admin bot with one-time Vault KV seeding' (#46) from benvin/gitea-vault-admin into main

Reviewed-on: #46

config/git.unkin.net/user/gitea-vault-admin.yaml

@@ -0,0 +1,21 @@
+# Purpose-built Gitea site-admin bot for the vault-plugin-secrets-gitea engine.
+# The engine seeds itself from this account's credentials (Basic Auth) to mint
+# and delete per-user tokens for any user. Its randomly generated password is
+# written ONCE to Vault KV (vault_seed_path below) and never updated after; the
+# Vault gitea engine reads that seed only when first creating gitea/config and
+# then rotates it (rotate-root) so only Vault holds the live password.
+#
+# A local (not external-auth) account with 2FA disabled is required so the
+# engine can change the password via the admin API during rotate-root.
+email: gitea-vault-admin@unkin.net
+full_name: "Gitea Vault Admin"
+description: "site-admin bot; credentials seeded to Vault for vault-plugin-secrets-gitea"
+# Site admin so the engine may mint/delete tokens for any user. No org/repo
+# creation; profile visible only to signed-in users.
+visibility: limited
+admin: true
+allow_create_organization: false
+max_repo_creation: 0
+# Seed this account's generated password to Vault KV (mount "kv") at this path,
+# where the Vault gitea secrets engine reads it at creation time. Written once.
+vault_seed_path: "service/vault/au/syd1/secret_backend/gitea/config"

environments/root.hcl

@@ -11,6 +11,11 @@ provider "woodpecker" {
   server = "https://ci.k8s.syd1.au.unkin.net"
 }
 
+# Address + token come from VAULT_ADDR / VAULT_TOKEN in the environment (the
+# Makefile authenticates via k8s auth before running terragrunt). Used to seed
+# bot-account credentials into Vault KV (see modules/user vault_seed_path).
+provider "vault" {}
+
 terraform {
   backend "consul" {
     address = "https://consul.service.consul"

modules/gitea_instance/main.tf

@@ -55,6 +55,8 @@ module "user" {
   allow_create_organization = each.value.allow_create_organization
   max_repo_creation         = each.value.max_repo_creation
   must_change_password      = each.value.must_change_password
+  vault_seed_path           = each.value.vault_seed_path
+  vault_seed_mount          = each.value.vault_seed_mount
 }
 
 module "team" {

modules/gitea_instance/modules/user/main.tf

@@ -35,3 +35,24 @@ resource "gitea_user" "this" {
     ignore_changes = [password]
   }
 }
+
+# Optional one-time seed of the account's credentials to Vault KV, for the
+# vault-plugin-secrets-gitea engine to consume when it first creates gitea/config.
+# random_password never regenerates (no keepers), so the seed is stable; the
+# ignore_changes below makes the write strictly create-only, so a later
+# rotate-root on the Vault side (which diverges the live password from this seed)
+# is never clobbered by a re-apply here.
+resource "vault_kv_secret_v2" "seed" {
+  count = var.vault_seed_path != null ? 1 : 0
+
+  mount = var.vault_seed_mount
+  name  = var.vault_seed_path
+  data_json = jsonencode({
+    admin_username = var.username
+    admin_password = random_password.this.result
+  })
+
+  lifecycle {
+    ignore_changes = [data_json]
+  }
+}

modules/gitea_instance/modules/user/terraform.tf

@@ -9,5 +9,9 @@ terraform {
       source  = "hashicorp/random"
       version = ">= 3.5"
     }
+    vault = {
+      source  = "hashicorp/vault"
+      version = ">= 4.3"
+    }
   }
 }

modules/gitea_instance/modules/user/variables.tf

@@ -67,3 +67,21 @@ variable "must_change_password" {
   type        = bool
   default     = false
 }
+
+variable "vault_seed_path" {
+  description = <<-EOT
+    Optional. When set, the account's generated password is seeded ONCE to Vault
+    KV at this secret name (under vault_seed_mount) as admin_username +
+    admin_password, for the vault-plugin-secrets-gitea engine to consume at
+    creation time. The write is create-only; subsequent changes are ignored so
+    the seed never churns (and never overwrites a rotated password).
+  EOT
+  type        = string
+  default     = null
+}
+
+variable "vault_seed_mount" {
+  description = "KV v2 mount holding the seeded credential (used only when vault_seed_path is set)"
+  type        = string
+  default     = "kv"
+}

modules/gitea_instance/terraform.tf

@@ -13,5 +13,9 @@ terraform {
       source  = "hashicorp/random"
       version = ">= 3.5"
     }
+    vault = {
+      source  = "hashicorp/vault"
+      version = ">= 4.3"
+    }
   }
 }

modules/gitea_instance/variables.tf

@@ -79,6 +79,8 @@ variable "user" {
     allow_create_organization = optional(bool, false)
     max_repo_creation         = optional(number, 0)
     must_change_password      = optional(bool, false)
+    vault_seed_path           = optional(string)
+    vault_seed_mount          = optional(string, "kv")
   }))
   default = {}
 }