Merge pull request #38 from 67P/healthcheck

Extract healthcheck into its own class

lib/kredits.js

@@ -1,6 +1,8 @@
 const ethers = require('ethers');
 const RSVP = require('rsvp');
 
+const Healthcheck = require('./utils/healthcheck');
+
 const ABIS = {
   Contributors: require('./abis/Contributors.json'),
   Operator: require('./abis/Operator.json'),
@@ -49,15 +51,9 @@ class Kredits {
   static setup(provider, signer, ipfsConfig = null) {
     console.log('Kredits.setup() is deprecated use new Kredits().init() instead');
     let ipfs = new IPFS(ipfsConfig);
-
-    return ipfs._ipfsAPI.id().catch((error) => {
-      throw new Error(`IPFS node not available; config: ${JSON.stringify(ipfsConfig)} - ${error.message}`);
-    }).then(() => {
-
-      return new Kredits(provider, signer).init().then((kredits) => {
-        kredits.ipfs = ipfs;
-        return kredits;
-      });
+    return new Kredits(provider, signer).init().then((kredits) => {
+      kredits.ipfs = ipfs;
+      return kredits;
     });
   }
 
@@ -98,6 +94,10 @@ class Kredits {
 
     return this.contracts[name];
   }
+
+  healthcheck() {
+    return new Healthcheck(this).check();
+  }
 }
 
 module.exports = Kredits;

lib/utils/healthcheck.js

@@ -0,0 +1,28 @@
+class Healthcheck {
+  constructor(kredits) {
+    this.kredits = kredits;
+  }
+
+  check() {
+    return this.kredits.ipfs._ipfsAPI.id()
+      .catch((error) => {
+        throw new Error(`IPFS node not available; config: ${JSON.stringify(this.kredits.ipfs.config)} - ${error.message}`);
+      })
+      .then(() => {
+        let promises = Object.keys(this.kredits.contracts).map((name) => {
+          let contractWrapper = this.kredits.contracts[name];
+          return this.kredits.provider.getCode(contractWrapper.contract.address).then((code) => {
+            // not sure if we always get the same return value if the code is not available
+            // so checking if it is < 5 long
+            if (code === '0x00' || code.length < 5) {
+              throw new Error(`Contract for: ${name} not found at ${contractWrapper.contract.address} on network ${this.kredits.provider.chainId}`);
+            }
+            return true;
+          });
+        });
+        return Promise.all(promises);
+      });
+  }
+}
+
+module.exports = Healthcheck;