Deno Fest 2023 @Tokyo - Chiezo

Transcript

1. Persisting logs with Deno KV
   by Shun Ueda (Chiezo @hasundue)
   

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2. Topics
   Deno KV Hackathon
   Time-series data with Deno KV
   Logging with std/log
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3. Who's speaking?
   Chiezo @hasundue
   Legal name: Shun Ueda
   A housemaker, PhD (Engineering)
   Field: high-temperature processing of materials
   e.g. Cooking
   Amateur programmer
   Vim/Neovim (2009-)
   Julia (2016-)
   Deno (2021-)
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4. Deno KV Hackathon
   https://deno.com/blog/deno-kv-
   hackathon
   Jun 12 - Jun 16, 2023
   I wanted CUTE merch!
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5. What's Deno KV?
   Deno KV is a key-value database built directly into the Deno runtime,
   ... available in the Deno CLI and on Deno Deploy.
   https://docs.deno.com/kv/manual
   const kv = await Deno.openKv();
   const prefs = {
   username: "ada",
   theme: "dark",
   language: "en-US",
   };
   const result = await kv.set(["preferences", "ada"], prefs);
   const entry = await kv.get(["preferences", "ada"]);
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6. What to build?
   Logging on Deno Deploy:
   ... After closing the logs page,
   all streamed logs are
   discarded.
   https://docs.deno.com/deploy
   /manual/logs
   Can be persisted with Deno KV?
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7. Branding
   Name ... Paleon (paleontology)
   Character ... A cute illustration
   of a child dinosaur who is
   conducting a paleontological
   study (by Bing Image Creator)
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8. Time-series data in Deno KV?
   JavaScript arrays as keys
   const key = [...prefix, Date.now(), crypto.randomUUID()];
   return kv.set(key, record);
   std/ulid is a better choice right now
   Ordering
   ... within a given type, they are ordered by their value.
   https://docs.deno.com/kv/manual/key_space
   const iter = kv.list({ start, end }, { limit, reverse });
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9. Designing APIs
   Abstraction of KV interface
   import { PaleonStorage } from "./mod.ts";
   type TestLogRecord = {
   datetime: Date;
   msg: string;
   };
   const paleon = await PaleonStorage.open("my-app");
   await paleon.write({ datetime: new Date(), msg: "hello" });
   for await (const record of paleon.read()) {
   console.log(record);
   }
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10. Integration with std/log
    import * as log from "$std/log/mod.ts";
    import { BaseHandler } from "$std/log/handlers.ts";
    class LocalPaleonHandler extends BaseHandler {
    ...
    }
    setup({
    handlers: {
    console: new handlers.ConsoleHandler("DEBUG"),
    paleon: await LocalPaleonHandler.init("DEBUG"),
    },
    loggers: {
    default: { level: "DEBUG", handlers: ["console", "paleon"] },
    },
    });
    const logger = getLogger();
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11. Demo SaaS with Fresh & Deno Deploy
    https://paleon.deno.dev
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12. Client integrated with std/log
    import * as log from "https://deno.land/std/log/mod.ts";
    import { PaleonAppHandler } from "./client.ts";
    log.setup({
    handlers: {
    console: new log.handlers.ConsoleHandler("DEBUG"),
    paleon: new PaleonAppHandler("DEBUG", {
    project: "{PROJECT_NAME}",
    id: "{DEPLOYMENT_ID}",
    }),
    },
    loggers: {
    default: { level: "DEBUG", handlers: ["console", "paleon"] },
    },
    });
    const logger = getLogger();
    logger.info("Hello Paleon!");
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13. Log Viewer with SSE streaming
    https://paleon.deno.dev/{PROJECT_NAME}/{DEPLOYMENT_ID}
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14. Finally...
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15. Conclusion
    Deno-kun is CUTE!!!
    Deno KV is well-designed
    Merch-driven development is productive
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16. See also...
    Other works by me:
    denopendabot ... https://github.com/apps/denopendabot
    Dependabot-like GitHub App on Deno Deploy
    deno-molt ... https://deno.land/x/molt
    Update dependencies using deno_graph
    and more ...
    Find me on:
    GitHub ... https://github.com/hasundue
    Slack → deno-ja, vim-jp
    Discord → Deno official
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