Merge pull request #9 from uber/dcValue

Add support for dcValue

Author: Raynos

README.md

@@ -31,12 +31,13 @@ A zero configuration configuration loader
 
 ```js
 // server.js
+var fs = require('fs');
 var fetchConfig = require('playdoh-server/config')
 
-var NODE_ENV = process.env.NODE_ENV
 var config = fetchConfig(__dirname, {
-    dc: NODE_ENV === 'production' ?
-        '/etc/playdoh/datacenter' : null
+    dcValue: fs.existsSync('/etc/zero-config/datacenter') ?
+        fs.readFileSync('/etc/zero-config/datacenter', 'utf8') :
+        null
 })
 
 var port = config.get("port")

errors.js

@@ -18,10 +18,10 @@ var MissingDatacenter = TypedError({
 
 var DatacenterRequired = TypedError({
     type: 'datacenter.option.required',
-    message: 'expected `opts.dc` to be passed to fetchConfig.\n' +
-        'must call `fetchConfig(__dirname, { dc: "..." }).\n' +
+    message: 'expected `opts.dcValue` to be passed to fetchConfig.\n' +
+        'must call `fetchConfig(__dirname, { dcValue: "..." }).\n' +
         'instead I got opts: {strOpts}.\n' +
-        '`opts.dc` is not optional when NODE_ENV is "production".\n' +
+        '`opts.dcValue` is not optional when NODE_ENV is "production".\n' +
         'SUGGESTED FIX: update the `fetchConfig()` callsite.\n'
 });
 

index.js

@@ -1,5 +1,6 @@
 var process = require('process');
 var EventEmitter = require('events').EventEmitter;
+var Result = require('raynos-rust-result');
 
 var errors = require('./errors.js');
 var readDatacenter = require('./read-datacenter.js');
@@ -21,16 +22,17 @@ function fetchConfigSync(dirname, opts) {
     // config is EventEmitter purely for `.emit('error', err)`
     var config = new EventEmitter();
 
-    var datacenterTuple = readDatacenter(opts);
+    var result = readDatacenter(opts);
 
-    if (datacenterTuple[0]) {
+    if (Result.isErr(result)) {
+        var err = Result.Err(result);
         // throw error async. this allows for breaking a 
         // circular dependency between config & logger.
         process.nextTick(function () {
-            config.emit('error', datacenterTuple[0]);
+            config.emit('error', err);
         });
     } else {
-        opts.datacenterValue = datacenterTuple[1];
+        opts.datacenterValue = Result.Ok(result);
     }
 
     var configState = getConfigState(dirname, opts);

package.json

@@ -18,7 +18,8 @@
     "error": "^4.1.1",
     "flatten-prototypes": "^3.0.0",
     "minimist": "^1.1.0",
-    "process": "^0.7.0"
+    "process": "^0.7.0",
+    "raynos-rust-result": "0.1.0-improvement3"
   },
   "devDependencies": {
     "coveralls": "^2.10.0",

read-datacenter.js

@@ -1,4 +1,5 @@
 var fs = require('fs');
+var Result = require('raynos-rust-result');
 
 var errors = require('./errors.js');
 
@@ -8,46 +9,51 @@ function readDatacenter(opts) {
     var env = opts.env || process.env;
     var NODE_ENV = env.NODE_ENV;
 
-    if (NODE_ENV === 'production' && !opts.dc) {
+    // specifying a datacenter is optional in dev but required
+    // in production.
+    if (NODE_ENV === 'production' && !opts.dc && !opts.dcValue) {
         throw errors.DatacenterRequired({
             strOpts: JSON.stringify(opts)
         });
     }
 
-    var result, error = null;
+    var result;
 
-    // specifying a datacenter is optional in dev but required
-    // in production.
-    if (opts.dc) {
-        var tuple = readFileOrError(opts.dc);
-        if (tuple[0]) {
-            var err = tuple[0];
+    if (opts.dcValue) {
+        result = Result.Ok({
+            'datacenter': opts.dcValue.replace(/\s/g, '')
+        });
+    } else if (opts.dc) {
+        var fileResult = readFileOrError(opts.dc);
+        if (Result.isErr(fileResult)) {
+            var err = Result.Err(fileResult);
             // create error synchronously for correct stack trace
             if (NODE_ENV === 'production') {
-                error = errors.DatacenterFileRequired({
+                result = Result.Err(errors.DatacenterFileRequired({
                     path: err.path,
                     errno: err.errno,
                     code: err.code,
                     syscall: err.syscall
-                });
+                }));
             } else {
-                error = errors.MissingDatacenter({
+                result = Result.Err(errors.MissingDatacenter({
                     path: err.path,
                     errno: err.errno,
                     code: err.code,
                     syscall: err.syscall
-                });
+                }));
             }
         } else {
-            result = {
-                'datacenter': tuple[1].replace(/\s/g, '')
-            };
+            result = Result.Ok({
+                'datacenter': Result.Ok(fileResult)
+                    .replace(/\s/g, '')
+            });
         }
     } else {
-        result = null;
+        result = Result.Ok(null);
     }
 
-    return [error, result];
+    return result;
 }
 
 // break try catch into small function to avoid v8 de-optimization
@@ -56,8 +62,8 @@ function readFileOrError(uri) {
     try {
         content = fs.readFileSync(uri, 'utf8');
     } catch (err) {
-        return [err, null];
+        return Result.Err(err);
     }
 
-    return [null, content];
+    return Result.Ok(content);
 }

test/index.js

@@ -137,6 +137,43 @@ test('config loads from datacenter file', withFixtures(__dirname, {
     assert.end();
 }));
 
+test('config loads from dcValue', withFixtures(__dirname, {
+    'config': {
+        'common.json': JSON.stringify({
+            a: 'a',
+            b: {
+                c: 'c',
+                d: 'd'
+            }
+        }),
+        'production.json': JSON.stringify({
+            b: {
+                c: 'c2'
+            }
+        }),
+        'production.peak1.json': JSON.stringify({
+            a: 'a3'
+        })
+    }
+}, function (assert) {
+    var env = {
+        'NODE_ENV': 'production'
+    };
+
+    var config = fetchConfig(__dirname, {
+        env: env,
+        dcValue: 'peak1'
+    });
+
+    assert.equal(config.get('datacenter'), 'peak1');
+    assert.equal(config.get('a'), 'a3');
+    assert.equal(config.get('b.c'), 'c2');
+    assert.equal(config.get('b.d'), 'd');
+    assert.deepEqual(config.get('b'), { c: 'c2', d: 'd' });
+
+    assert.end();
+}));
+
 test('config reads a datacenter file', withFixtures(__dirname, {
     datacenter: 'peak1'
 }, function (assert) {
@@ -201,7 +238,7 @@ test('will load from --config', withFixtures(__dirname, {
     assert.end();
 }));
 
-test('no opts.dc in production', function (assert) {
+test('no opts.dcValue in production', function (assert) {
     var err = catchFn(function () {
         fetchConfig(__dirname, {
             env: { NODE_ENV: 'production' }
@@ -210,8 +247,8 @@ test('no opts.dc in production', function (assert) {
 
     assert.ok(err);
     assert.equal(err.type, 'datacenter.option.required');
-    assert.ok(/expected `opts.dc`/.test(err.message));
-    assert.ok(/`opts.dc` is not optional/.test(err.message));
+    assert.ok(/expected `opts.dcValue`/.test(err.message));
+    assert.ok(/`opts.dcValue` is not optional/.test(err.message));
 
     assert.end();
 });