Embedded the frontend in the binary, and built it in the build script

`npm run sync` in web/ copies the build output (web/dist, from npm run build)
to internal/frontend/dist, which the binary embeds. Go can't embed from
outside the package's directory (web/ is also outside the Go module), hence
the copy. Only dist/.gitkeep is committed, so a fresh clone still compiles,
and a binary built without syncing first serves no frontend.

job-search serve serves server.frontend.dir if it is set, or else the
embedded build, or warns that there is no frontend. scripts/build.sh builds
and syncs the frontend before building, running npm ci first for a release
or when web/node_modules is missing.

.gitignore

@@ -39,3 +39,8 @@ build/
 release/
 
 mock-data/
+
+# The frontend's build output, copied by npm run sync in web/ for embedding.
+# .gitkeep is kept, as Go can't embed a missing directory.
+internal/frontend/dist/*
+!internal/frontend/dist/.gitkeep

README.md

@@ -15,11 +15,24 @@ scripts/build.sh                    # build/job-search-<version>
 scripts/build.sh --release          # also package release/job-search-<version>-<arch>.tar.gz
 ```
 
-The build script runs `go generate ./...`, which needs `swag` installed (see
+The build script builds the frontend and copies it into place for embedding
+(`npm run build` and `npm run sync` in `web/`, which need Node and npm; it
+runs `npm ci` first for a release, or when `web/node_modules` is missing). It
+then runs `go generate ./...`, which needs `swag` installed (see
 [Installation of dev tools](#installation-of-dev-tools)), and stamps the
 version from the latest git tag. A build from untagged commits is marked as a development build
 and isn't packaged unless `--force` is also given.
 
+The frontend (`web/`) is embedded in the binary. Without the build script,
+build it and copy it into place first, or the binary serves no frontend
+(`job-search serve` warns):
+
+```bash
+cd web && npm ci && npm run build && npm run sync   # web/dist -> internal/frontend/dist
+```
+
+Setting `server.frontend.dir` serves a build from disk instead.
+
 During development, `go run -tags sqlite_fts5 ./cmd/jobsearch` works as well.
 The `sqlite_fts5` tag is needed for the database's title search (see
 [Testing](#testing)).
@@ -157,6 +170,8 @@ second one fails with "address already in use".
 | `internal/logging` | slog setup and the HTTP access log |
 | `internal/mock` | Mock external services |
 | `internal/version` | Version information set at build time |
+| `internal/frontend` | Serves the frontend's build output; embeds `dist/`, copied there from `web/dist` by `npm run sync` |
+| `web` | The frontend (see [web](web/README.md)) |
 
 
 ## Testing

internal/cli/serve/command.go

@@ -31,7 +31,9 @@ func NewCommand(opts *cli.Options) *cobra.Command {
 		Use:   "serve",
 		Short: "Serve the REST API, WebSocket and frontend, and fetch from sources",
 		Long: `Serve the REST API under /api, the WebSocket endpoint under /ws, and the
-frontend's files from server.frontend.dir under / if it is set.
+frontend under /: the files in server.frontend.dir if it is set, or else the
+build embedded in the binary (copied there by npm run sync in web/ before
+building), if there is one.
 
 It also runs a worker for every enabled source, as fetcher service does,
 saving what they fetch to database.file if it is set, and pushing an
@@ -196,9 +198,10 @@ set, the API serves the stored opportunities under /api/opportunities.`,
 }
 
 // serverOptions returns the server's options for conf: the access log, if
-// server.access_log is set, and the frontend's files, if server.frontend.dir
-// is (checked first). closeAccessLog closes the access log; call it once the
-// server has stopped.
+// server.access_log is set, and the frontend's files: those in
+// server.frontend.dir if it is set (checked first), or else the build
+// embedded in the binary, if there is one. closeAccessLog closes the access
+// log; call it once the server has stopped.
 func serverOptions(
 	conf *config.JSCServer,
 ) ([]server.Option, func() error, error) {
@@ -225,7 +228,15 @@ func serverOptions(
 			)
 		}
 		options = append(options, server.WithFrontend(files))
+		return options, closeAccessLog, nil
 	}
 
+	files := frontend.Embedded()
+	if files == nil {
+		slog.Warn("no frontend embedded and server.frontend.dir not set")
+		return options, closeAccessLog, nil
+	}
+	options = append(options, server.WithFrontend(files))
+
 	return options, closeAccessLog, nil
 }

internal/config/README.md

@@ -179,7 +179,7 @@ The `server` section is split into a number of sub-sections:
 
 | Key | Type | Default | Notes |
 |---|---|---|---|
-| `server.frontend.dir` | string | | Directory of the frontend's build output, holding `index.html`; empty: no frontend is served (there is no embedded build yet) |
+| `server.frontend.dir` | string | | Directory of the frontend's build output, holding `index.html`; empty: the build embedded in the binary (see `npm run sync` in `web/`), or no frontend if it has none |
 | `server.frontend.immutable_prefix` | string | | Where Vite emits content-hashed files, cached for a year; empty: `/assets/` |
 | `server.frontend.index_cache_control` | string | | `Cache-Control` of HTML and other files without a hash; empty: `no-cache` |
 

internal/config/conf_server_frontend.go

@@ -9,7 +9,7 @@ const JSCKServerFrontend string = "frontend"
 
 // JSCServerFrontend configures how the server serves the frontend. Dir is
 // the directory of the frontend's build output (holding index.html); empty
-// means no frontend is served, as there is no embedded build yet.
+// means the build embedded in the binary, or no frontend if it has none.
 // ImmutablePrefix is where Vite emits content-hashed files, cached for a
 // year; empty means "/assets/". IndexCacheControl is the Cache-Control of
 // HTML and other files without a hash; empty means "no-cache".

internal/frontend/embed.go

@@ -0,0 +1,24 @@
+package frontend
+
+import (
+	"embed"
+	"io/fs"
+)
+
+// dist holds the frontend's build output, copied from web/dist by `npm run
+// sync` in web/. Only dist/.gitkeep is committed (Go can't embed a missing
+// directory), so a binary built without syncing first has no frontend.
+//
+//go:embed all:dist
+var dist embed.FS
+
+// Embedded returns the frontend's build output embedded in the binary, or
+// nil if none was synced before it was built (there is no index.html).
+func Embedded() fs.FS {
+	files, err := fs.Sub(dist, "dist")
+	if err != nil || CheckFS(files) != nil {
+		return nil
+	}
+
+	return files
+}

scripts/build.sh

@@ -39,6 +39,14 @@ if [ "$GIT_COMMIT" != "" ]; then
     LD_FLAGS="$LD_FLAGS -X git.avsdev.uk/Go/job-search/internal/version.GitCommit=${GIT_COMMIT}"
 fi
 
+# Build the frontend and copy it to internal/frontend/dist, where the binary
+# embeds it. npm ci installs exactly the lock file's versions: always for a
+# release, otherwise only when nothing is installed yet.
+if [[ $DO_RELEASE -eq 1 || ! -d web/node_modules ]]; then
+    (cd web && npm ci)
+fi
+(cd web && npm run build && npm run sync)
+
 # Process any generators
 go generate ./...
 

web/CODE_CONVENTIONS.md

@@ -15,7 +15,8 @@ npm run lint           # eslint .
 npm run format:check   # prettier --check .
 npm run format         # prettier --write .: formats every file
 npm run generate:api   # regenerate src/types/api.ts from the backend's OpenAPI description
-npm run build          # typecheck, then vite build
+npm run build          # typecheck, then vite build into dist/
+npm run sync           # copy dist/ to ../internal/frontend/dist/, which the backend embeds
 npm run dev            # dev server; /api and /ws go to the backend (API_PROXY_TARGET, default localhost:9393)
 ```
 
@@ -79,7 +80,7 @@ if (isRelease(parsed)) { ... }
 | `src/primitives/` | Solid primitives: state and loading, no markup (`createX.ts`)                                      |
 | `src/components/` | Components, one exported component per file                                                        |
 | `src/lib/`        | Plain functions: no Solid, no DOM where avoidable                                                  |
-| `scripts/`        | Development scripts run by npm, in TypeScript (`generateApiTypes.ts`)                              |
+| `scripts/`        | Development scripts run by npm, in TypeScript (`generateApiTypes.ts`, `syncDist.ts`)               |
 
 - Components' files are PascalCase, named after the component
   (`MarkMenu.tsx`). Other files are usually camelCase (`format.ts`); the

web/README.md

@@ -14,6 +14,10 @@ default address (`http://localhost:9393`). To use another, copy `.env.example`
 to `.env` and set `API_PROXY_TARGET`. `VITE_API_BASE_URL` changes the `/api`
 prefix for production builds.
 
+`npm run build` type-checks and builds the app into `dist/`. `npm run sync`
+then copies `dist/` to `../internal/frontend/dist/`, where the backend embeds
+it: the next Go build of `job-search` serves it. The copy isn't committed.
+
 Before committing, `npm run check` type-checks, lints (ESLint) and checks
 formatting (Prettier); `npm run format` formats everything. See
 [CODE_CONVENTIONS.md](CODE_CONVENTIONS.md).

web/package.json

@@ -12,7 +12,8 @@
     "format": "prettier --write .",
     "format:check": "prettier --check .",
     "check": "npm run typecheck && npm run lint && npm run format:check",
-    "generate:api": "node scripts/generateApiTypes.ts"
+    "generate:api": "node scripts/generateApiTypes.ts",
+    "sync": "node scripts/syncDist.ts"
   },
   "dependencies": {
     "solid-js": "^1.9.3"

web/scripts/syncDist.ts

@@ -0,0 +1,24 @@
+// Copies the frontend's build output, dist/ (from npm run build), to
+// ../internal/frontend/dist/, which the backend embeds, so the next Go build
+// of job-search serves this frontend:
+//
+//   npm run build && npm run sync
+//
+// The old copy is replaced entirely, so files from an earlier build don't
+// linger. Its .gitkeep, the only file there that's committed, is put back:
+// Go can't embed a directory that doesn't exist.
+import { cpSync, existsSync, rmSync, writeFileSync } from 'node:fs';
+
+const source = 'dist';
+const target = '../internal/frontend/dist';
+
+if (!existsSync(`${source}/index.html`)) {
+  console.error(`${source}/index.html not found: run npm run build first`);
+  process.exit(1);
+}
+
+rmSync(target, { recursive: true, force: true });
+cpSync(source, target, { recursive: true });
+writeFileSync(`${target}/.gitkeep`, '');
+
+console.log(`Copied ${source}/ to ${target}/`);