drv-daemon: ad-hoc Builds + queue-runner handoff

Cargo.toml

@@ -1,6 +1,12 @@
 [workspace]
 
-members  = [ "subprojects/hydra-builder", "subprojects/hydra-queue-runner", "subprojects/crates/*" ]
+members = [
+    "subprojects/hydra-builder",
+    "subprojects/hydra-drv-daemon",
+    "subprojects/hydra-evaluator",
+    "subprojects/hydra-queue-runner",
+    "subprojects/crates/*",
+]
 resolver = "2"
 
 [workspace.package]
@@ -29,10 +35,13 @@ futures = "0.3"
 futures-util = "0.3"
 gethostname = "1"
 h2 = "0.4"
+harmonia-protocol = { git = "https://github.com/nix-community/harmonia.git" }
 harmonia-store-aterm = { git = "https://github.com/nix-community/harmonia.git" }
 harmonia-store-core = { git = "https://github.com/nix-community/harmonia.git" }
+harmonia-store-remote = { git = "https://github.com/nix-community/harmonia.git" }
 harmonia-utils-base-encoding = { git = "https://github.com/nix-community/harmonia.git" }
 harmonia-utils-hash = { git = "https://github.com/nix-community/harmonia.git" }
+harmonia-utils-io = { git = "https://github.com/nix-community/harmonia.git" }
 hashbrown = "0.16"
 http = "1.1"
 http-body-util = "0.1"
@@ -94,7 +103,12 @@ uuid = "1.16"
 zerocopy = { version = "0.8", features = [ "derive" ] }
 
 [patch.crates-io]
+harmonia-nar                 = { git = "https://github.com/nix-community/harmonia.git" }
+harmonia-protocol            = { git = "https://github.com/nix-community/harmonia.git" }
+harmonia-protocol-derive     = { git = "https://github.com/nix-community/harmonia.git" }
 harmonia-store-aterm         = { git = "https://github.com/nix-community/harmonia.git" }
 harmonia-store-core          = { git = "https://github.com/nix-community/harmonia.git" }
+harmonia-store-remote        = { git = "https://github.com/nix-community/harmonia.git" }
 harmonia-utils-base-encoding = { git = "https://github.com/nix-community/harmonia.git" }
 harmonia-utils-hash          = { git = "https://github.com/nix-community/harmonia.git" }
+harmonia-utils-io            = { git = "https://github.com/nix-community/harmonia.git" }

Procfile

@@ -1,6 +1,7 @@
 hydra-evaluator: ./foreman/start-evaluator.sh
 hydra-queue-runner: ./foreman/start-queue-runner.sh
 hydra-builder: ./foreman/start-builder.sh
+hydra-drv-daemon: ./foreman/start-drv-daemon.sh
 hydra-notify: ./foreman/start-notify.sh
 hydra-server: ./foreman/start-hydra.sh
 manual: ./foreman/start-manual.sh

flake.nix

@@ -83,6 +83,10 @@
           hydra-builder = self'.callPackage ./subprojects/hydra-builder/package.nix {
             inherit nixComponents;
           };
+          hydra-drv-daemon = self'.callPackage ./subprojects/hydra-drv-daemon/package.nix { };
+          hydra-evaluator = self'.callPackage ./subprojects/hydra-evaluator/package.nix {
+            inherit nixComponents;
+          };
         });
       mkHydraBuilder =
         { pkgs, nixComponents }:
@@ -137,6 +141,8 @@
           hydra-linters
           hydra-queue-runner
           hydra-builder
+          hydra-drv-daemon
+          hydra-evaluator
           ;
       };
 
@@ -153,6 +159,8 @@
 
         builder = forEachSystemIncDarwin (system: packages.${system}.hydra-builder);
 
+        drvDaemon = forEachSystem (system: packages.${system}.hydra-drv-daemon);
+
         nixosTests = import ./nixos-tests.nix {
           inherit forEachSystem nixpkgs nixosModules;
         };
@@ -280,6 +288,8 @@
               hydra-linters
               hydra-queue-runner
               hydra-builder
+              hydra-evaluator
+              hydra-drv-daemon
               ;
             foreman = pkgs.callPackage ./packaging/foreman/package.nix {
               foreman-src = foreman;

foreman/start-drv-daemon.sh

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+. ./foreman/common.sh
+
+wait_for_postgres
+
+# wait until the hydra database exists (hydra-server creates it)
+while ! psql -h "$HYDRA_PG_SOCKET_DIR" -p "$HYDRA_PG_PORT" -d hydra -c 'SELECT 1' >/dev/null 2>&1; do sleep 1; done
+
+wait_for_hydra_server
+
+DAEMON_SOCK="$HYDRA_DATA/drv-daemon.sock"
+UPSTREAM_SOCK="${NIX_DAEMON_SOCKET_PATH:-/nix/var/nix/daemon-socket/socket}"
+
+export HYDRA_DBA="postgres://${USER}@localhost:$HYDRA_PG_PORT/hydra"
+
+exec hydra-drv-daemon \
+    --socket "$DAEMON_SOCK" \
+    --upstream-socket "$UPSTREAM_SOCK"

foreman/start-evaluator.sh

@@ -9,4 +9,11 @@ wait_for_postgres
 wait_for_hydra_db
 wait_for_hydra_server
 
+# Route IFD store ops through the drv-daemon when its socket is up.
+# When the socket is missing the evaluator falls back to the local nix-daemon.
+DAEMON_SOCK="$HYDRA_DATA/drv-daemon.sock"
+if [ -S "$DAEMON_SOCK" ]; then
+    export NIX_REMOTE="unix://$DAEMON_SOCK"
+fi
+
 HYDRA_CONFIG=$HYDRA_DATA/hydra.conf exec hydra-evaluator