Feat/admin command (#2022)

* WIP: cli admin command

* configure admin command to load ledger admin view

an express service was implemented, which serves the default site from
the instances

test plan: run `sourcecred admin` and browse to the ledger admin
instance to ensure it loads

* implement GET and POST handlers for ledger.json

The GET localhost:6006/data/ledger.json request will return
the ledger.json file if it exists

The POST request will write the submitted json to disk at
./data/ledger.json

test plan: run `$ sourcecred admin` or `$ yarn admin` then
post some json to the path by doing something like
```
$ curl --header "Content-Type: application/json" \
  --request POST \
  --data '{"username":"derp","password":"slerp"}' \
http://localhost:6006/data/ledger.json
```
and ensure there are no errors.

then
```
$ curl http://localhost:6006/data/ledger.json
```
and ensure the submitted json is returned

* remove unused variables

* Add Ledger to the UI load result

Note: This will fail if there is no ledger file. An empty JSON array is
technically a valid ledger, so if you want to update the example
instance just use:

`echo [] > data/ledger.json`

Test plan: Not yet tested, integrate into frontend

* implement button to save ledger to disk

test-plan: put and empty array ("[]") in the instance's ledger.json
file, then start the admin service "yarn admin" or "sourcecred admin"
then generate some ledger data using the identity interface and ensure
it saves back to disk

* Load ledger from disk for real

* add text middleware to express libdefs

* move ledger disk saving from application/json to text/plain

ledger.json files are encoded in such a way that they are indented and
escaped for some readability from the CLI. using json content-typing
will discard that escaping. By treating the payload as raw text, that
encoding is preserved

test-plan: modify and save a canonically serialized ledger.json file
from the browser frontend and observe that the spacing is preserved in
the file saved to disk

* remove unused deps and improve server console prompt

test-plan: start the admin server and ensure the frontend can create and
modify identities, then save the ledger.json file to disk successfully

* comments and capitalization

test-plan: `yarn flow` should still pass after this change

* remove redundant static middleware

we don't need to configure a static service for a subdirectory of a
statically-served directory

test-plan: ensure ledger.json can still be fetched either via curl or
the web frontend when the admin service is running

* remove address from fetch post request

if we're fetching to/from the parent address that served the javascript
we're calling from, an address is unnecessary

test-plan: make sure updated ledger.json files still POST back to disk

* add instance check

attempt to load the instance configurtion. If the config cannot be
loaded, an error will be throw indicating that the sourcecred.json file
cannot be found

test-plan: run `sourcecred admin` outside of an instance directory and
ensure it fails while looking for sourcecred.json

run `sourcecred admin` in an instance directory and ensure the service
starts up

Co-authored-by: Dandelion Mané <decentralion@dandelion.io>

flow-typed/npm/express_v4.17.x.js

@@ -323,6 +323,14 @@ declare type express$UrlEncodedOptions = {
   ...
 }
 
+declare type express$TextOptions = {
+  defaultCharset?: string,
+  inflate?: boolean,
+  limit?: mixed,
+  type?: mixed,
+  verify?: Function,
+}
+
 declare module "express" {
   declare export type RouterOptions = express$RouterOptions;
   declare export type CookieOptions = express$CookieOptions;
@@ -343,6 +351,7 @@ declare module "express" {
     // If you try to call like a function, it will use this signature
     <Req: express$Request, Res: express$Response>(): express$Application<Req, Res>,
     json: (opts: ?JsonOptions) => express$Middleware<>,
+    text: (opts: ?express$TextOptions) => express$Middleware<>,
     // `static` property on the function
     static: <Req: express$Request, Res: express$Response>(root: string, options?: Object) => express$Middleware<Req, Res>,
     // `Router` property on the function

src/cli/admin.js

@@ -0,0 +1,47 @@
+// @flow
+
+import type {Command} from "./command";
+import {loadInstanceConfig} from "./common";
+
+const fs = require("fs");
+const express = require("express");
+
+function die(std, message) {
+  std.err("fatal: " + message);
+  return 1;
+}
+
+const adminCommand: Command = async (args, std) => {
+  const basedir = process.cwd();
+  // check to ensure service is running within an instance directory
+  await loadInstanceConfig(basedir);
+
+  if (args.length !== 0) {
+    return die(std, "usage: sourcecred admin");
+  }
+
+  const server = express();
+
+  // serve the static admin site and all subdirectories
+  // also enables GETing data/ledger.json
+  server.use(express.static("."));
+
+  // middleware that parses text request bodies for us
+  server.use(express.text());
+  // write posted ledger.json files to disk
+  server.post("/data/ledger.json", (req, res) => {
+    try {
+      fs.writeFileSync("./data/ledger.json", req.body, "utf8");
+    } catch (e) {
+      res.status(500).send(`error saving ledger.json file: ${e}`);
+    }
+    res.status(201).end();
+  });
+
+  server.listen(6006, () => {
+    console.info("admin server running: navigate to http://localhost:6006");
+  });
+  return 0;
+};
+
+export default adminCommand;

src/cli/sourcecred.js

@@ -8,6 +8,7 @@ import graph from "./graph";
 import score from "./score";
 import site from "./site";
 import go from "./go";
+import admin from "./admin";
 import help from "./help";
 
 const sourcecred: Command = async (args, std) => {
@@ -32,6 +33,8 @@ const sourcecred: Command = async (args, std) => {
       return site(args.slice(1), std);
     case "go":
       return go(args.slice(1), std);
+    case "admin":
+      return admin(args.slice(1), std);
     default:
       std.err("fatal: unknown command: " + JSON.stringify(args[0]));
       std.err("fatal: run 'sourcecred help' for commands and usage");

src/ui/components/AdminApp.js

@@ -34,7 +34,10 @@ const customRoutes = (loadResult: LoadSuccess) => [
     <Redirect to="/explorer" />
   </Route>,
   <Route key="admin" exact path="/admin">
-    <LedgerAdmin credView={loadResult.credView} />
+    <LedgerAdmin
+      credView={loadResult.credView}
+      initialLedger={loadResult.ledger}
+    />
   </Route>,
 ];
 

src/ui/components/LedgerAdmin.js

@@ -8,10 +8,11 @@ import {AliasSelector} from "./AliasSelector";
 
 export type Props = {|
   +credView: CredView,
+  +initialLedger: Ledger,
 |};
 
-export const LedgerAdmin = ({credView}: Props) => {
+export const LedgerAdmin = ({credView, initialLedger}: Props) => {
-  const [ledger, setLedger] = useState<Ledger>(new Ledger());
+  const [ledger, setLedger] = useState<Ledger>(initialLedger);
   const [nextIdentityName, setIdentityName] = useState<string>("");
   const [currentIdentity, setCurrentIdentity] = useState<Identity | null>(null);
   const [promptString, setPromptString] = useState<string>("Add Identity:");
@@ -91,6 +92,21 @@ export const LedgerAdmin = ({credView}: Props) => {
           type="submit"
           value={currentIdentity ? "update username" : "create identity"}
         />
+        <br />
+        <input
+          type="button"
+          value="save ledger to disk"
+          onClick={() => {
+            fetch("data/ledger.json", {
+              headers: {
+                Accept: "text/plain",
+                "Content-Type": "text/plain",
+              },
+              method: "POST",
+              body: ledger.serialize(),
+            });
+          }}
+        />
         {currentIdentity && (
           <>
             <br />

src/ui/load.js

@@ -2,17 +2,23 @@
 import * as pluginId from "../api/pluginId";
 import {CredView} from "../analysis/credView";
 import {fromJSON as credResultFromJSON} from "../analysis/credResult";
+import {Ledger, parser as ledgerParser} from "../ledger/ledger";
 
 export type LoadResult = LoadSuccess | LoadFailure;
 export type LoadSuccess = {|
   +type: "SUCCESS",
   +credView: CredView,
+  +ledger: Ledger,
   +bundledPlugins: $ReadOnlyArray<pluginId.PluginId>,
 |};
 export type LoadFailure = {|+type: "FAILURE", +error: any|};
 
 export async function load(): Promise<LoadResult> {
-  const queries = [fetch("output/credResult.json"), fetch("/sourcecred.json")];
+  const queries = [
+    fetch("output/credResult.json"),
+    fetch("/sourcecred.json"),
+    fetch("data/ledger.json"),
+  ];
   const responses = await Promise.all(queries);
 
   for (const response of responses) {
@@ -26,7 +32,9 @@ export async function load(): Promise<LoadResult> {
     const credResult = credResultFromJSON(json);
     const credView = new CredView(credResult);
     const {bundledPlugins} = await responses[1].json();
-    return {type: "SUCCESS", credView, bundledPlugins};
+    const ledgerJson = await responses[2].json();
+    const ledger = ledgerParser.parseOrThrow(ledgerJson);
+    return {type: "SUCCESS", credView, bundledPlugins, ledger};
   } catch (e) {
     console.error(e);
     return {type: "FAILURE", error: e};