History tips (#6711)

* split sidebar note into multilines (just in code)

* note in sidebar - grammatical fixes, added history tip

* add history tip in dygraph chart, on the left side, when panned beyond its available past

* bundled/compiled dashboard.js

* invisible left side of history-tip was preventing further panning to the past, fix that

* change history link from "https://docs.netdata.cloud/daemon/config/#global-section-options" to
"https://docs.netdata.cloud/docs/configuration-guide/#increase-the-metrics-retention-period"

1 files changed, 36 insertions, 1 deletions

diff --git a/web/gui/src/dashboard.js/charting/dygraph.js b/web/gui/src/dashboard.js/charting/dygraph.js
index a60af18b83..f34d2f4aa1 100644
--- a/web/gui/src/dashboard.js/charting/dygraph.js
+++ b/web/gui/src/dashboard.js/charting/dygraph.js
@@ -483,8 +483,28 @@ NETDATA.dygraphChartCreate = function (state, data) {
             NETDATA.globalSelectionSync.stop();
         },
         underlayCallback: function (canvas, area, g) {
-
             // the chart is about to be drawn
+
+            // update history_tip_element
+            if (state.tmp.dygraph_history_tip_element) {
+                const xHookRightSide = g.toDomXCoord(state.netdata_first);
+                if (xHookRightSide > area.x) {
+                    state.tmp.dygraph_history_tip_element_displayed = true;
+                    // group the styles for possible better performance
+                    state.tmp.dygraph_history_tip_element.setAttribute(
+                      'style',
+                      `display: block; left: ${area.x}px; right: calc(100% - ${xHookRightSide}px);`
+                    )
+                } else {
+                    if (state.tmp.dygraph_history_tip_element_displayed) {
+                        // additional check just for performance
+                        // don't update the DOM when it's not needed
+                        state.tmp.dygraph_history_tip_element.style.display = 'none';
+                        state.tmp.dygraph_history_tip_element_displayed = false;
+                    }
+                }
+            }
+
             // this function renders global highlighted time-frame
 
             if (NETDATA.globalChartUnderlay.isActive()) {
@@ -953,6 +973,21 @@ NETDATA.dygraphChartCreate = function (state, data) {
     state.tmp.dygraph_instance = new Dygraph(state.element_chart,
         data.result.data, state.tmp.dygraph_options);
 
+
+    state.tmp.dygraph_history_tip_element = document.createElement('div');
+    state.tmp.dygraph_history_tip_element.innerHTML = `
+        <span class="dygraph__history-tip-content">
+          Want to extend your history of real-time metrics?
+          <br />
+           <a href="https://docs.netdata.cloud/docs/configuration-guide/#increase-the-metrics-retention-period" target=_blank>
+             Configure Netdata's <b>history</b></a>
+           or use the <a href="https://docs.netdata.cloud/database/engine/" target=_blank>DB engine</a>.
+        </span>
+    `;
+    state.tmp.dygraph_history_tip_element.className = 'dygraph__history-tip';
+    state.element_chart.appendChild(state.tmp.dygraph_history_tip_element);
+
+
     state.tmp.dygraph_force_zoom = false;
     state.tmp.dygraph_user_action = false;
     state.tmp.dygraph_last_rendered = Date.now();