nameservice: save contract address on disk

Previously the contract address was hardcoded only,
it is now saved on disc so killing the server would
not cause the address to be lost if it wasn't
committed.

Change-Id: Iaa3592288b9e6d84f780878e02bb684ccf25e2bb

index.js

@@ -10,13 +10,11 @@ var web3 = new Web3();
 
 Object.getPrototypeOf(web3.eth).awaitConsensus = function(txhash, mined_cb) {
     ethP = this;
-    filter = this.filter('latest');         // XXX make async
     var tries = 5;
+    filter = this.filter('latest');
     filter.watch(function(error, result) {
         if (error)
             console.log("watch error: " + error);
-        if (result)
-            console.log("watch result: " + result);
         var receipt = ethP.getTransactionReceipt(txhash);
         if (receipt && receipt.transactionHash == txhash) {
             console.log(receipt);
@@ -34,6 +32,7 @@ console.log(coinbase);
 var balance = web3.eth.getBalance(coinbase);
 console.log(balance.toString(10));
 
+var REG_ADDR_FILE = "contractAddress.txt";
 var REG_ADDR = "0x1b364554e859d3277d3477ef6bf21113464e2392";
 var REG_ABI = [{"constant":true,"inputs":[{"name":"_a","type":"address"}],"name":"name","outputs":[{"name":"o_name","type":"bytes32"}],"type":"function"},{"constant":true,"inputs":[{"name":"_name","type":"bytes32"}],"name":"owner","outputs":[{"name":"","type":"address"}],"type":"function"},{"constant":true,"inputs":[{"name":"_name","type":"bytes32"}],"name":"content","outputs":[{"name":"","type":"bytes32"}],"type":"function"},{"constant":true,"inputs":[{"name":"_name","type":"bytes32"}],"name":"addr","outputs":[{"name":"","type":"address"}],"type":"function"},{"constant":false,"inputs":[{"name":"_name","type":"bytes32"}],"name":"reserve","outputs":[],"type":"function"},{"constant":true,"inputs":[{"name":"_name","type":"bytes32"}],"name":"subRegistrar","outputs":[{"name":"o_subRegistrar","type":"address"}],"type":"function"},{"constant":false,"inputs":[{"name":"_name","type":"bytes32"},{"name":"_owner","type":"address"},{"name":"_a","type":"address"}],"name":"reserveFor","outputs":[],"type":"function"},{"constant":false,"inputs":[{"name":"_name","type":"bytes32"},{"name":"_newOwner","type":"address"}],"name":"transfer","outputs":[],"type":"function"},{"constant":false,"inputs":[{"name":"_name","type":"bytes32"},{"name":"_registrar","type":"address"}],"name":"setSubRegistrar","outputs":[],"type":"function"},{"constant":false,"inputs":[],"name":"Registrar","outputs":[],"type":"function"},{"constant":false,"inputs":[{"name":"_name","type":"bytes32"},{"name":"_a","type":"address"},{"name":"_primary","type":"bool"}],"name":"setAddress","outputs":[],"type":"function"},{"constant":false,"inputs":[{"name":"_name","type":"bytes32"},{"name":"_content","type":"bytes32"}],"name":"setContent","outputs":[],"type":"function"},{"constant":false,"inputs":[{"name":"_name","type":"bytes32"}],"name":"disown","outputs":[],"type":"function"},{"constant":true,"inputs":[{"name":"_name","type":"bytes32"}],"name":"register","outputs":[{"name":"","type":"address"}],"type":"function"},{"anonymous":false,"inputs":[{"indexed":true,"name":"name","type":"bytes32"}],"name":"Changed","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"name","type":"bytes32"},{"indexed":true,"name":"addr","type":"address"},{"indexed":false,"name":"owner","type":"address"}],"name":"PrimaryChanged","type":"event"}];
 
@@ -70,25 +69,32 @@ function waitForGaz(want, cb) {
 }
 
 function loadContract() {
-    console.log("Loading name contract from blockchain at " + REG_ADDR);
-    web3.eth.getCode(REG_ADDR, function(error, result) {
-        //console.log("Contract code at " + REG_ADDR + ": " + result);
-        if (result == "0x") {
-            console.log("Contract not found at " + REG_ADDR);
-            initContract();
+    fs.readFile(REG_ADDR_FILE, function(err, content) {
+        if (!err) {
+            REG_ADDR = content;
         } else {
-            regContract = web3.eth.contract(REG_ABI);
-            regContract.at(REG_ADDR, function(err, result) {
-                console.log("Contract found and loaded from " + REG_ADDR);
-                if(!err) {
-                    reg = result;
-                    startServer();
-                }
-                else {
-                    console.error("err: " + err);
-                }
-            });
+            console.log("Can't read contract address: " + err);
         }
+        console.log("Loading name contract from blockchain at " + REG_ADDR);
+        web3.eth.getCode(REG_ADDR, function(error, result) {
+            //console.log("Contract code at " + REG_ADDR + ": " + result);
+            if (result == "0x") {
+                console.log("Contract not found at " + REG_ADDR);
+                initContract();
+            } else {
+                regContract = web3.eth.contract(REG_ABI);
+                regContract.at(REG_ADDR, function(err, result) {
+                    console.log("Contract found and loaded from " + REG_ADDR);
+                    if(!err) {
+                        reg = result;
+                        startServer();
+                    }
+                    else {
+                        console.error("err: " + err);
+                    }
+                });
+            }
+        });
     });
 }
 
@@ -112,6 +118,7 @@ function initContract() {
                         } else {
                             console.log("Contract mined! Address: " + contract.address);
                             REG_ADDR = contract.address;
+                            fs.writeFile(REG_ADDR_FILE, REG_ADDR);
                             reg = contract;
                             startServer();
                         }