Merge pull request #907 from prometheus/better-autocomplete

Enable autocomplete anywhere in expression.

web/blob/static/js/graph.js

@@ -73,7 +73,6 @@ Prometheus.Graph.prototype.initialize = function() {
   self.rangeInput = self.queryForm.find("input[name=range_input]");
   self.stackedBtn = self.queryForm.find(".stacked_btn");
   self.stacked = self.queryForm.find("input[name=stacked]");
-  self.insertMetric = self.queryForm.find("select[name=insert_metric]");
   self.refreshInterval = self.queryForm.find("select[name=refresh]");
 
   self.consoleTab = graphWrapper.find(".console");
@@ -90,14 +89,6 @@ Prometheus.Graph.prototype.initialize = function() {
     }
   });
 
-  // Return moves focus back to expr instead of submitting.
-  self.insertMetric.bind("keydown", "return", function(e) {
-    self.expr.focus();
-    self.expr.val(self.expr.val());
-
-    return e.preventDefault();
-  })
-
   self.error = graphWrapper.find(".error").hide();
   self.graphArea = graphWrapper.find(".graph_area");
   self.graph = self.graphArea.find(".graph");
@@ -160,19 +151,83 @@ Prometheus.Graph.prototype.initialize = function() {
   self.queryForm.find("button[name=inc_end]").click(function() { self.increaseEnd(); });
   self.queryForm.find("button[name=dec_end]").click(function() { self.decreaseEnd(); });
 
-  self.insertMetric.change(function() {
-    self.expr.selection("replace", {text: self.insertMetric.val(), mode: "before"});
-    self.expr.focus(); // refocusing
-  });
-
-  self.populateInsertableMetrics();
+  self.populateAutocompleteMetrics();
 
   if (self.expr.val()) {
     self.submitQuery();
   }
 };
 
-Prometheus.Graph.prototype.populateInsertableMetrics = function() {
+// Returns true if the character at "pos" in the expression string "str" looks
+// like it could be a metric name (if it's not in a string or a label matchers
+// section).
+function isPotentialMetric(str, pos) {
+  var quote = null;
+  var inMatchers = false;
+
+  for (var i = 0; i < pos; i++) {
+    var ch = str[i];
+
+    // Skip over escaped characters (quotes or otherwise) in strings.
+    if (quote !== null && ch === "\\") {
+      i += 1;
+      continue;
+    }
+
+    // Track if we are entering or leaving a string.
+    switch (ch) {
+      case quote:
+        quote = null;
+        break;
+      case '"':
+      case "'":
+        quote = ch;
+        break;
+    }
+
+    // Ignore curly braces in strings.
+    if (quote) {
+      continue;
+    }
+
+    // Track whether we are in curly braces (label matchers).
+    switch (ch) {
+      case "{":
+        inMatchers = true;
+        break;
+      case "}":
+        inMatchers = false;
+        break;
+    }
+  }
+
+  return !inMatchers && quote === null;
+}
+
+// Returns the current word under the cursor position in $input.
+function currentWord($input) {
+  var wordRE = new RegExp("[a-zA-Z0-9:_]");
+  var pos = $input.prop("selectionStart");
+  var str = $input.val();
+  var len = str.length;
+  var start = pos;
+  var end = pos;
+
+  while (start > 0 && str[start-1].match(wordRE)) {
+    start--;
+  }
+  while (end < len && str[end].match(wordRE)) {
+    end++;
+  }
+
+  return {
+    start: start,
+    end: end,
+    word: $input.val().substring(start, end)
+  };
+}
+
+Prometheus.Graph.prototype.populateAutocompleteMetrics = function() {
   var self = this;
   $.ajax({
       method: "GET",
@@ -183,12 +238,40 @@ Prometheus.Graph.prototype.populateInsertableMetrics = function() {
           self.showError("Error loading available metrics!")
           return;
         }
-        var metrics = json.data;
-        for (var i = 0; i < metrics.length; i++) {
-          self.insertMetric[0].options.add(new Option(metrics[i], metrics[i]));
-        }
+
+        // For the typeahead autocompletion, we need to remember where to put
+        // the cursor after inserting an autocompleted word (we want to put it
+        // after that word, not at the end of the entire input string).
+        var afterUpdatePos = null;
+
         self.expr.typeahead({
-          source: metrics,
+          // Needs to return true for autocomplete items that should be matched
+          // by the current input.
+          matcher: function(item) {
+            var cw = currentWord(self.expr);
+            if (cw.word.length !== 0 &&
+                item.toLowerCase().indexOf(cw.word.toLowerCase()) > -1 &&
+                isPotentialMetric(self.expr.val(), cw.start)) {
+              return true;
+            }
+            return false;
+          },
+          // Returns the entire string to which the input field should be set
+          // upon selecting an item from the autocomplete list.
+          updater: function(item) {
+            var str = self.expr.val();
+            var cw = currentWord(self.expr);
+            afterUpdatePos = cw.start + item.length;
+            return str.substring(0, cw.start) + item + str.substring(cw.end, str.length);
+          },
+          // Is called *after* the input field has been set to the string
+          // returned by the "updater" callback. We want to move the cursor to
+          // the end of the actually inserted word here.
+          afterSelect: function(item) {
+            self.expr.prop("selectionStart", afterUpdatePos);
+            self.expr.prop("selectionEnd", afterUpdatePos);
+          },
+          source: json.data,
           items: "all"
         });
         // This needs to happen after attaching the typeahead plugin, as it

web/blob/static/js/graph_template.handlebar

@@ -12,9 +12,6 @@
             <div class="row">
               <div class="col-lg-10">
                 <input class="btn btn-primary execute_btn" type="submit" value="Execute" name="submit">
-                <select class="form-control expression_select" name="insert_metric">
-                  <option value="">- insert metric at cursor -</option>
-                </select>
               </div>
             </div>
             <div class="row">