feat(prometheus): began work on prometheus query model

public/app/plugins/datasource/prometheus/prom_query.ts

@@ -0,0 +1,79 @@
+import {
+  QueryPartDef,
+  QueryPart,
+  functionRenderer,
+  suffixRenderer,
+  identityRenderer,
+  quotedIdentityRenderer,
+} from 'app/core/components/query_part/query_part';
+
+var index = [];
+var categories = {
+  Functions: [],
+};
+
+export class PromQuery {
+  target: any;
+  metric: string;
+  range: string;
+  filters: any[];
+  functions: any[];
+  templateSrv: any;
+  scopedVars: any;
+
+  constructor(target, templateSrv?, scopedVars?) {
+    this.target = target;
+    this.templateSrv = templateSrv;
+    this.scopedVars = scopedVars;
+  }
+
+  render() {
+    var query = this.target.metric;
+    if (this.target.range) {
+      query += '[' + this.target.range + ']';
+    }
+
+    for (let funcModel of this.target.functions) {
+      var partDef = index[funcModel.type];
+      if (!partDef) {
+        continue;
+      }
+
+      var part = new QueryPart(funcModel, partDef);
+      query = part.render(query);
+    }
+
+    return query;
+  }
+}
+
+export function createPart(part): any {
+  var def = index[part.type];
+  if (!def) {
+    throw {message: 'Could not find query part ' + part.type};
+  }
+
+  return new QueryPart(part, def);
+}
+
+function register(options: any) {
+  index[options.type] = new QueryPartDef(options);
+  options.category.push(index[options.type]);
+}
+
+function addFunctionStrategy(model, partModel) {
+  model.functions.push(partModel);
+}
+
+register({
+  type: 'rate',
+  addStrategy: addFunctionStrategy,
+  category: categories.Functions,
+  params: [],
+  defaultParams: [],
+  renderer: functionRenderer,
+});
+
+export function getCategories() {
+  return categories;
+}

public/app/plugins/datasource/prometheus/specs/query_specs.ts

@@ -0,0 +1,23 @@
+import {describe, beforeEach, it, sinon, expect} from 'test/lib/common';
+
+import {PromQuery} from '../prom_query';
+
+describe.only('PromQuery', function() {
+  var templateSrv = {replace: val => val};
+
+  describe('render series with mesurement only', function() {
+    it('should generate correct query', function() {
+      var query = new PromQuery({
+        metric: 'cpu',
+        range: '5m',
+        functions: [
+          {type: 'rate', params: []}
+        ]
+      }, templateSrv, {});
+
+      var queryText = query.render();
+      expect(queryText).to.be('rate(cpu[5m])');
+    });
+  });
+
+});