Use dotenv for cluster selection

.gitignore

@@ -3,4 +3,4 @@
 /store
 /.cargo
 /dist
-cluster.txt
+.env

.travis.yml

@@ -32,5 +32,5 @@ script:
   - npm run build:program-c
   - npm run build:program-rust
   - npm run test:program-rust
-  - npm run cluster:local
+  - npm run cluster:localnet
   - npm run start

README.md

@@ -258,7 +258,7 @@ $ npm run cluster:devnet
 
 To point back to the local cluster:
 ```bash
-$ npm run cluster:local
+$ npm run cluster:localnet
 ```
 
 ## Expand your skills with advanced examples

cluster-devnet.env

@@ -0,0 +1,2 @@
+LIVE=1
+CLUSTER=devnet

cluster-mainnet-beta.env

@@ -0,0 +1,2 @@
+LIVE=1
+CLUSTER=mainnet-beta

cluster-testnet.env

@@ -0,0 +1,2 @@
+LIVE=1
+CLUSTER=testnet

package.json

@@ -25,10 +25,10 @@
     "build:program-rust": "./src/program-rust/do.sh build && npm run clean:store",
     "clean:program-rust": "./src/program-rust/do.sh clean && rm -rf ./dist && npm run clean:store",
     "test:program-rust": "./src/program-rust/do.sh test",
-    "cluster:local": "npm run clean:store && rm -f cluster.txt",
-    "cluster:devnet": "npm run clean:store && echo devnet > cluster.txt",
-    "cluster:testnet": "npm run clean:store && echo testnet > cluster.txt",
-    "cluster:mainnet-beta": "npm run clean:store && echo mainnet-beta > cluster.txt",
+    "cluster:localnet": "npm run clean:store && rm -f .env",
+    "cluster:devnet": "npm run clean:store && cp cluster-devnet.env .env",
+    "cluster:testnet": "npm run clean:store && cp cluster-testnet.env .env",
+    "cluster:mainnet-beta": "npm run clean:store && cp cluster-mainnet-beta.env .env",
     "localnet:update": "solana-localnet update",
     "localnet:up": "set -x; solana-localnet down; set -e; solana-localnet up",
     "localnet:down": "solana-localnet down",
@@ -57,6 +57,7 @@
     "body-parser": "^1.18.3",
     "buffer-layout": "^1.2.0",
     "css-loader": "^3.1.0",
+    "dotenv": "8.2.0",
     "eslint": "^6.1.0",
     "eslint-loader": "^4.0.0",
     "eslint-plugin-import": "^2.13.0",

url.js

@@ -2,41 +2,30 @@
 // environment. By default, `LIVE=1` will connect to the devnet cluster.
 
 import {clusterApiUrl, Cluster} from '@solana/web3.js';
-import fs from 'mz/fs';
+import dotenv from 'dotenv';
 
 function chooseCluster(): Cluster | undefined {
-  let cluster;
-  if (process.env.LIVE) {
-    cluster = process.env.CLUSTER;
-  } else if (fs.existsSync('cluster.txt')) {
-    cluster = fs
-      .readFileSync('cluster.txt')
-      .toString()
-      .replace(/(\r\n|\n|\r| )/gm, '');
-  }
-
-  if (cluster) {
-    switch (cluster) {
-      case 'devnet':
-      case 'testnet':
-      case 'mainnet-beta': {
-        return cluster;
-      }
-      default:
-        throw 'Unknown cluster: ' + cluster;
+  dotenv.config();
+  if (!process.env.LIVE) return;
+  switch (process.env.CLUSTER) {
+    case 'devnet':
+    case 'testnet':
+    case 'mainnet-beta': {
+      return process.env.CLUSTER;
     }
   }
+  throw 'Unknown cluster "' + process.env.CLUSTER + '", check the .env file';
 }
 
 export const cluster = chooseCluster();
 
 export const url =
   process.env.RPC_URL ||
-  (cluster ? clusterApiUrl(cluster, false) : 'http://localhost:8899');
+  (process.env.LIVE ? clusterApiUrl(cluster, false) : 'http://localhost:8899');
 
 export const urlTls =
   process.env.RPC_URL ||
-  (cluster ? clusterApiUrl(cluster, true) : 'http://localhost:8899');
+  (process.env.LIVE ? clusterApiUrl(cluster, true) : 'http://localhost:8899');
 
 export let walletUrl =
   process.env.WALLET_URL || 'https://solana-example-webwallet.herokuapp.com/';