factor out nixos conf (#526)

Reviewed-on: Fediversity/Fediversity#526

deployment/data-model.nix

@@ -29,6 +29,33 @@ let
       else
         lib.strings.toJSON v
     );
+  withPackages = packages: {
+    makeWrapperArgs = [
+      "--prefix"
+      "PATH"
+      ":"
+      "${lib.makeBinPath packages}"
+    ];
+  };
+  writeConfig =
+    {
+      system,
+      module,
+      root-path,
+      deployment-type,
+      deployment-name,
+      args,
+    }:
+    builtins.toString (
+      pkgs.writers.writeText "configuration.nix" ''
+        import ${root-path}/deployment/nixos.nix {
+          system = "${system}";
+          configuration = (import "${root-path}/${module}" (builtins.fromJSON "${
+            lib.replaceStrings [ "\"" ] [ "\\\"" ] (lib.strings.toJSON args)
+          }")).${deployment-name}.${deployment-type}.nixos-configuration;
+        }
+      ''
+    );
 
   functionType = submodule ./function.nix;
   application-resources = submodule {
@@ -85,6 +112,8 @@ let
       };
     };
   };
+  # FIXME allow custom deployment types
+  # FIXME make deployments environment resources?
   deployment-type = attrTag {
     ssh-host = mkOption {
       description = "A deployment by SSH to update a single existing NixOS host.";
@@ -134,30 +163,27 @@ let
                   ;
                 environment = {
                   key_file = key-file;
-                  deployment_name = deployment-name;
-                  root_path = root-path;
                   ssh_opts = sshOpts;
                   inherit
-                    system
                     host
                     username
-                    module
-                    args
                     ;
-                  deployment_type = "ssh-host";
+                  nixos_conf = writeConfig {
+                    inherit
+                      system
+                      module
+                      args
+                      deployment-name
+                      root-path
+                      ;
+                    deployment-type = "ssh-host";
+                  };
                 };
               in
               pkgs.writers.writeBashBin "deploy-sh.sh"
-                {
+                (withPackages [
-                  makeWrapperArgs = [
+                  pkgs.jq
-                    "--prefix"
+                ])
-                    "PATH"
-                    ":"
-                    "${lib.makeBinPath [
-                      pkgs.jq
-                    ]}"
-                  ];
-                }
                 ''
                   env ${
                     toString (lib.mapAttrsToList (k: v: "${k}=\"${toBash v}\"") environment)
@@ -219,32 +245,29 @@ let
                   ;
                 environment = {
                   key_file = key-file;
-                  deployment_name = deployment-name;
-                  root_path = root-path;
                   ssh_opts = sshOpts;
                   inherit
-                    system
                     host
                     username
-                    module
-                    args
                     ;
-                  deployment_type = "tf-host";
+                  nixos_conf = writeConfig {
+                    inherit
+                      system
+                      module
+                      args
+                      deployment-name
+                      root-path
+                      ;
+                    deployment-type = "tf-host";
+                  };
                 };
                 tf-env = pkgs.callPackage ./run/tf-single-host/tf-env.nix { };
               in
               pkgs.writers.writeBashBin "deploy-tf.sh"
-                {
+                (withPackages [
-                  makeWrapperArgs = [
+                  pkgs.jq
-                    "--prefix"
+                  (pkgs.callPackage ./run/tf-single-host/tf.nix { inherit sources; })
-                    "PATH"
+                ])
-                    ":"
-                    "${lib.makeBinPath [
-                      pkgs.jq
-                      (pkgs.callPackage ./run/tf-single-host/tf.nix { inherit sources; })
-                    ]}"
-                  ];
-                }
                 ''
                   env ${toString (lib.mapAttrsToList (k: v: "TF_VAR_${k}=\"${toBash v}\"") environment)} \
                   tf_env=${tf-env} bash ./deployment/run/tf-single-host/run.sh

deployment/run/ssh-single-host/run.sh

@@ -1,6 +1,6 @@
 #! /usr/bin/env bash
 set -xeuo pipefail
-declare username host system module args deployment_name deployment_type key_file root_path ssh_opts
+declare username host key_file ssh_opts nixos_conf
 IFS=" " read -r -a ssh_opts <<< "$( (echo "$ssh_opts" | jq -r '@sh') | tr -d \'\")"
 
 # DEPLOY
@@ -20,18 +20,16 @@ if [[ -n "$key_file" ]]; then
 fi
 destination="$username@$host"
 
-command=(nix-instantiate --show-trace --expr "
+command=(nix-instantiate --show-trace "${nixos_conf}")
-  import $root_path/deployment/nixos.nix {
-    system = \"$system\";
-    configuration = (import \"$root_path/$module\" (builtins.fromJSON ''$args'')).$deployment_name.$deployment_type.nixos-configuration;
-  }
-")
 
 # INSTANTIATE
 # instantiate the config in /nix/store
 "${command[@]}" -A out_path
 
 # get the realized derivation to deploy
+"${command[@]}" --show-trace --eval --strict --json
+
+# FIXME explore import/readFile as ways to instantiate the derivation, potentially allowing to realize the store path up-front from Nix?
 outPath=$(nix-store --realize "$("${command[@]}" --show-trace --eval --strict --json | jq -r '.drv_path')")
 # deploy the config by nix-copy-closure
 NIX_SSHOPTS="${sshOpts[*]}" nix-copy-closure --to "$destination" "$outPath" --gzip --use-substitutes

deployment/run/tf-single-host/main.tf

@@ -18,11 +18,8 @@ resource "terraform_data" "nixos" {
   # - `data` always runs, which is slow for deploy and especially build.
   triggers_replace = [
     data.external.hash.result,
+    var.nixos_conf,
     var.host,
-    var.module,
-    var.args,
-    var.root_path,
-    var.deployment_type,
   ]
 
   provisioner "local-exec" {
@@ -33,17 +30,11 @@ resource "terraform_data" "nixos" {
     # so are generally discouraged in TF.
     working_dir = path.root
     environment = {
-      system = var.system
+      nixos_conf = var.nixos_conf
       username = var.username
       host = var.host
-      module = var.module
-      host = var.host
-      args = var.args
       key_file = var.key_file
-      deployment_name = var.deployment_name
-      root_path = var.root_path
       ssh_opts = var.ssh_opts
-      deployment_type = var.deployment_type
     }
     # TODO: refactor back to command="ignoreme" interpreter=concat([]) to protect sensitive data from error logs?
     # TODO: build on target?

deployment/run/tf-single-host/variables.tf

@@ -1,7 +1,6 @@
-variable "system" {
+variable "nixos_conf" {
-  description = "The architecture of the system to deploy to."
+  description = "The path to the NixOS configuration to deploy."
   type = string
-  default = "x86_64-linux"
 }
 
 variable "username" {
@@ -15,40 +14,13 @@ variable "host" {
   type = string
 }
 
-variable "module" {
-  description = "The module to call to obtain the NixOS configuration from."
-  type = string
-}
-
-variable "args" {
-  description = "The arguments with which to call the module to obtain the NixOS configuration."
-  type = string
-  default = "{}"
-}
-
 variable "key_file" {
   description = "path to the user's SSH private key"
   type = string
 }
 
-variable "deployment_name" {
-  description = "The name of the deployment for which to obtain the NixOS configuration."
-  type = string
-}
-
-variable "root_path" {
-  description = "The path to the root of the repository."
-  type = string
-}
-
 variable "ssh_opts" {
   description = "Extra SSH options (`-o`) to use."
   type = string
   default = "[]"
 }
-
-variable "deployment_type" {
-  description = "A `deployment-type` from the Fediversity data model, for grabbing the desired NixOS configuration."
-  type = string
-  default = "tf-host"
-}