Milo: Limit text field to 256 characters

milo/api/resp/build.go

 // Copyright 2015 The LUCI Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //      http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 267 matching lines @@
         // Alias, if true, means that this link is an [alias link].
         Alias bool `json:",omitempty"`
 }
 
 // NewLink does just about what you'd expect.
 func NewLink(label, url string) *Link {
         return &Link{Link: model.Link{Label: label, URL: url}}
 }
 
 func (comp *BuildComponent) toModelSummary() model.Summary {
+        text := comp.Text
+        // Max length for a datastore text field is 1500 char, but for summary purposes
+        // we don't really need anything much longer than 256 char or so.
+        const maxTextLen = 256
+        sliceIdx := 0
+        // Make sure we don't cut off characters inbetween runes.
+        for idx := range text {
+                if idx > maxTextLen {
+                        break
+                }
+                sliceIdx = idx
+        }
+        text = text[:sliceIdx]
         return model.Summary{
                 Status: comp.Status,
                 Start:  comp.Started,
                 End:    comp.Finished,
-                Text:   comp.Text,
+                Text:   text,
         }
 }
 
 // SummarizeTo summarizes the data into a given model.BuildSummary.
 func (rb *MiloBuild) SummarizeTo(c context.Context, bs *model.BuildSummary) error {
         bs.Summary = rb.Summary.toModelSummary()
         if rb.Summary.Status == model.Running {
                 // Assume the last step is the current step.
                 if len(rb.Components) > 0 {
                         cs := rb.Components[len(rb.Components)-1]
@@ skipping 27 matching lines @@
                 }
                 if rb.SourceStamp.Changelist != nil {
                         bs.Patches = append(bs.Patches, model.PatchInfo{
                                 Link:        rb.SourceStamp.Changelist.Link,
                                 AuthorEmail: rb.SourceStamp.AuthorEmail,
                         })
                 }
         }
         return nil
 }