1 files changed, 169 insertions, 0 deletions
diff --git a/deno/tools/service.ts b/deno/tools/service.ts
new file mode 100644
index 0000000..1172473
--- /dev/null
+++ b/deno/tools/service.ts
@@ -0,0 +1,169 @@
+import { dirname, join, relative } from "@std/path";
+import { copySync, existsSync, walkSync } from "@std/fs";
+import { parse } from "@std/dotenv";
+import { distinct } from "@std/collections";
+// @ts-types="npm:@types/mustache"
+import Mustache from "mustache";
+
+import { defineYargsModule, DEMAND_COMMAND_MESSAGE } from "./yargs.ts";
+
+const MUSTACHE_RENDER_OPTIONS: Mustache.RenderOptions = {
+  tags: ["@@", "@@"],
+  escape: (value: unknown) => String(value),
+};
+
+function mustacheParse(template: string) {
+  return Mustache.parse(template, MUSTACHE_RENDER_OPTIONS.tags);
+}
+
+function mustacheRender(template: string, view: Record<string, string>) {
+  return Mustache.render(template, view, {}, MUSTACHE_RENDER_OPTIONS);
+}
+
+function getVariableKeysOfTemplate(template: string): string[] {
+  return distinct(
+    mustacheParse(template)
+      .filter((v) => v[0] === "name")
+      .map((v) => v[1]),
+  );
+}
+
+function loadTemplatedConfigFiles(
+  files: string[],
+): Record<string, string> {
+  console.log("Scan config files ...");
+  const config: Record<string, string> = {};
+  for (const file of files) {
+    console.log(`  from file ${file}`);
+    const text = Deno.readTextFileSync(file);
+    for (const [key, valueText] of Object.entries(parse(text))) {
+      // TODO: dotenv silently override old values, so everything will be new for now.
+      console.log(`    (${key in config ? "override" : "new"}) ${key}`);
+      getVariableKeysOfTemplate(valueText).forEach((name) => {
+        if (!(name in config)) {
+          throw new Error(
+            `Variable ${name} is not defined yet, perhaps due to typos or wrong order.`,
+          );
+        }
+      });
+      config[key] = mustacheRender(valueText, config);
+    }
+  }
+  return config;
+}
+
+const TEMPLATE_FILE_EXT = ".template";
+
+class TemplateDir {
+  templates: { path: string; ext: string; text: string; vars: string[] }[] = [];
+  plains: { path: string }[] = [];
+
+  constructor(public dir: string) {
+    console.log(`Scan template dir ${dir} ...`);
+    Array.from(
+      walkSync(dir, { includeDirs: false, followSymlinks: true }),
+    ).forEach(({ path }) => {
+      path = relative(this.dir, path);
+      if (path.endsWith(TEMPLATE_FILE_EXT)) {
+        console.log(`  (template) ${path}`);
+        const text = Deno.readTextFileSync(join(dir, path));
+        this.templates.push({
+          path,
+          ext: TEMPLATE_FILE_EXT,
+          text,
+          vars: getVariableKeysOfTemplate(text),
+        });
+      } else {
+        console.log(`  (plain) ${path}`);
+        this.plains.push({ path });
+      }
+    });
+  }
+
+  allNeededVars() {
+    return distinct(this.templates.flatMap((t) => t.vars));
+  }
+
+  generate(vars: Record<string, string>, generatedDir?: string) {
+    console.log(
+      `Generate to dir ${generatedDir ?? "[dry-run]"} ...`,
+    );
+
+    const undefinedVars = this.allNeededVars().filter((v) => !(v in vars));
+    if (undefinedVars.length !== 0) {
+      throw new Error(
+        `Needed variables are not defined: ${undefinedVars.join(", ")}`,
+      );
+    }
+
+    if (generatedDir != null) {
+      if (existsSync(generatedDir)) {
+        console.log(`  delete old generated dir`);
+        Deno.removeSync(generatedDir, { recursive: true });
+      }
+
+      for (const file of this.plains) {
+        const [source, destination] = [
+          join(this.dir, file.path),
+          join(generatedDir, file.path),
+        ];
+        console.log(`  copy ${file.path}`);
+        Deno.mkdirSync(dirname(destination), { recursive: true });
+        copySync(source, destination);
+      }
+      for (const file of this.templates) {
+        const path = file.path.slice(0, -file.ext.length);
+        const destination = join(generatedDir, path);
+        console.log(`  generate ${path}`);
+        const rendered = mustacheRender(file.text, vars);
+        Deno.mkdirSync(dirname(destination), { recursive: true });
+        Deno.writeTextFileSync(destination, rendered);
+      }
+    }
+  }
+}
+
+export default defineYargsModule({
+  command: "service",
+  aliases: ["sv"],
+  describe: "Manage services.",
+  builder: (builder) => {
+    return builder
+      .option("project-dir", {
+        type: "string",
+      })
+      .demandOption("project-dir")
+      .command({
+        command: "gen-tmpl",
+        describe: "Generate files from templates",
+        builder: (builder) => {
+          return builder
+            .option("dry-run", {
+              type: "boolean",
+              default: true,
+            })
+            .strict();
+        },
+        handler: (argv) => {
+          const { projectDir, dryRun } = argv;
+
+          const config = loadTemplatedConfigFiles(
+            [
+              join(projectDir, "data/config"),
+              join(projectDir, "services/config.template"),
+            ],
+          );
+
+          new TemplateDir(
+            join(projectDir, "services/templates"),
+          ).generate(
+            config,
+            dryRun ? undefined : join(projectDir, "services/generated"),
+          );
+          console.log("Done!");
+        },
+      })
+      .demandCommand(1, DEMAND_COMMAND_MESSAGE);
+  },
+  handler: () => {},
+});