Implement opt-in/out for pull requests

frontend.go

@@ -104,12 +104,18 @@ func resultPage(w http.ResponseWriter, r *http.Request) {
       return
     }
 
+    var optIn bool
+    if strings.ToUpper(r.URL.Query().Get("optin")) == "ON" {
+      optIn = true
+    }
+
     secret := Secret(16)
     repo := Repo{
       Project: project,
       Slug: repo,
       Token: accessToken,
       Secret: secret,
+      OptIn: optIn,
     }
 
     name := "web"

repo.go

@@ -27,6 +27,7 @@ type Repo struct {
   Slug string
   Token string
   Secret string
+  OptIn bool
 }
 
 type Repos []Repo

templates/auth.html

@@ -15,6 +15,16 @@
       <input type="text" class="form-control" id="repoInput" name="repo" aria-describedby="repoHelp" placeholder="Enter your project slug">
       <small id="repoHelp" class="form-text text-muted">Your project slug is the Github user- and repository name separated by a slash e.g. ganggo/federation</small>
     </div>
+    <div class="form-check mb-3">
+      <input type="checkbox" class="form-check-input" id="optinInput" name="optin" describedby="optinHelp">
+      <label class="form-check-label" for="optinInput">Check if you want to opt-in on a new test</label>
+      <small id="optinHelp" class="form-text text-muted">
+        That would mean that tests are triggered if you specify <code>[ci]</code> in the PR title, message
+        or if the PR was tagged with <span class="badge badge-primary">ci</span>. If you leave the box unchecked
+        tests will be triggered on every pull-request. However you can skip them by writing <code>[ci skip]</code> in the PR title,
+        message or if the PR was tagged with <span class="badge badge-primary">ci skip</span>.
+      </small>
+    </div>
     <button type="submit" class="btn btn-primary">Submit</button>
   </form>
 </div>

webhook.go

@@ -25,6 +25,7 @@ import (
   "encoding/json"
   "github.com/jinzhu/gorm"
   _ "github.com/jinzhu/gorm/dialects/sqlite"
+  "strings"
 )
 
 func webhook(w http.ResponseWriter, r *http.Request) {
@@ -76,6 +77,46 @@ func webhook(w http.ResponseWriter, r *http.Request) {
   //  return
   //}
 
+  var flagExists = false
+  var buildFlag = "ci skip"
+  if repo.OptIn {
+    buildFlag = "ci"
+  }
+
+  // check PR title and body for [ci] or [ci skip] flag
+  if pr.Title != nil && pr.Body != nil &&
+  strings.Contains(strings.ToLower(*pr.Title),
+      fmt.Sprintf("[%s]", buildFlag)) &&
+  strings.Contains(strings.ToLower(*pr.Body),
+      fmt.Sprintf("[%s]", buildFlag)) {
+    flagExists = true
+  }
+
+  if !flagExists {
+    // check labels for build flag if we haven't already found it
+    for _, label := range pr.Labels {
+      if label.Name != nil && strings.Contains(
+          strings.ToLower(*label.Name), buildFlag) {
+        flagExists = true
+        break
+      }
+    }
+  }
+
+  // ignoring pull-request! Repository is set
+  // to opt-in and no build flag was found
+  if repo.OptIn && !flagExists {
+    fmt.Fprintf(w, `{}`)
+    return
+  }
+
+  // ignoring pull-request! Repository is set
+  // to opt-out and a skip flag was found
+  if !repo.OptIn && flagExists {
+    fmt.Fprintf(w, `{}`)
+    return
+  }
+
   build := Build{
     RepoID: repo.ID,
     Matrix: fmt.Sprintf(