Split Bitbucket Server comments if over max length

- Refactor the comment split method into a common package

server/events/vcs/bitbucketserver/client.go

@@ -11,11 +11,17 @@ import (
 	"regexp"
 	"strings"
 
+	"github.com/runatlantis/atlantis/server/events/vcs/common"
+
 	"github.com/pkg/errors"
 	"github.com/runatlantis/atlantis/server/events/models"
 	"gopkg.in/go-playground/validator.v9"
 )
 
+// maxCommentLength is the maximum number of chars allowed by Bitbucket in a
+// single comment.
+const maxCommentLength = 32768
+
 type Client struct {
 	HttpClient  *http.Client
 	Username    string
@@ -117,8 +123,22 @@ func (b *Client) GetProjectKey(repoName string, cloneURL string) (string, error)
 	return matches[1], nil
 }
 
-// CreateComment creates a comment on the merge request.
+// CreateComment creates a comment on the merge request. It will write multiple
+// comments if a single comment is too long.
 func (b *Client) CreateComment(repo models.Repo, pullNum int, comment string) error {
+	sepEnd := "\n```\n**Warning**: Output length greater than max comment size. Continued in next comment."
+	sepStart := "Continued from previous comment.\n```diff\n"
+	comments := common.SplitComment(comment, maxCommentLength, sepEnd, sepStart)
+	for _, c := range comments {
+		if err := b.postComment(repo, pullNum, c); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// postComment actually posts the comment. It's a helper for CreateComment().
+func (b *Client) postComment(repo models.Repo, pullNum int, comment string) error {
 	bodyBytes, err := json.Marshal(map[string]string{"text": comment})
 	if err != nil {
 		return errors.Wrap(err, "json encoding")

server/events/vcs/common/comment_splitter.go

@@ -0,0 +1,37 @@
+package common
+
+import (
+	"math"
+)
+
+// SplitComment splits comment into a slice of comments that are under maxSize.
+// It appends sepEnd to all comments that have a following comment.
+// It prepends sepStart to all comments that have a preceding comment.
+func SplitComment(comment string, maxSize int, sepEnd string, sepStart string) []string {
+	if len(comment) <= maxSize {
+		return []string{comment}
+	}
+
+	maxWithSep := maxSize - len(sepEnd) - len(sepStart)
+	var comments []string
+	numComments := int(math.Ceil(float64(len(comment)) / float64(maxWithSep)))
+	for i := 0; i < numComments; i++ {
+		upTo := min(len(comment), (i+1)*maxWithSep)
+		portion := comment[i*maxWithSep : upTo]
+		if i < numComments-1 {
+			portion += sepEnd
+		}
+		if i > 0 {
+			portion = sepStart + portion
+		}
+		comments = append(comments, portion)
+	}
+	return comments
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}

server/events/vcs/common/comment_splitter_test.go

@@ -0,0 +1,63 @@
+// Copyright 2017 HootSuite Media Inc.
+//
+// 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,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// Modified hereafter by contributors to runatlantis/atlantis.
+
+package common_test
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/runatlantis/atlantis/server/events/vcs/common"
+
+	. "github.com/runatlantis/atlantis/testing"
+)
+
+// If under the maximum number of chars, we shouldn't split the comments.
+func TestSplitComment_UnderMax(t *testing.T) {
+	comment := "comment under max size"
+	split := common.SplitComment(comment, len(comment)+1, "sepEnd", "sepStart")
+	Equals(t, []string{comment}, split)
+}
+
+// If the comment needs to be split into 2 we should do the split and add the
+// separators properly.
+func TestSplitComment_TwoComments(t *testing.T) {
+	comment := strings.Repeat("a", 1000)
+	sepEnd := "-sepEnd"
+	sepStart := "-sepStart"
+	split := common.SplitComment(comment, len(comment)-1, sepEnd, sepStart)
+
+	expCommentLen := len(comment) - len(sepEnd) - len(sepStart) - 1
+	expFirstComment := comment[:expCommentLen]
+	expSecondComment := comment[expCommentLen:]
+	Equals(t, 2, len(split))
+	Equals(t, expFirstComment+sepEnd, split[0])
+	Equals(t, sepStart+expSecondComment, split[1])
+}
+
+// If the comment needs to be split into 4 we should do the split and add the
+// separators properly.
+func TestSplitComment_FourComments(t *testing.T) {
+	comment := strings.Repeat("a", 1000)
+	sepEnd := "-sepEnd"
+	sepStart := "-sepStart"
+	max := (len(comment) / 4) + len(sepEnd) + len(sepStart)
+	split := common.SplitComment(comment, max, sepEnd, sepStart)
+
+	expMax := len(comment) / 4
+	Equals(t, []string{
+		comment[:expMax] + sepEnd,
+		sepStart + comment[expMax:expMax*2] + sepEnd,
+		sepStart + comment[expMax*2:expMax*3] + sepEnd,
+		sepStart + comment[expMax*3:]}, split)
+}

server/events/vcs/github_client.go

@@ -16,28 +16,19 @@ package vcs
 import (
 	"context"
 	"fmt"
-	"math"
 	"net/url"
 	"strings"
 
+	"github.com/runatlantis/atlantis/server/events/vcs/common"
+
 	"github.com/google/go-github/github"
 	"github.com/pkg/errors"
 	"github.com/runatlantis/atlantis/server/events/models"
 )
 
-// detailsClose is appended to a comment that is so long we split it into
-// multiple comments.
-const detailsClose = "\n```\n</details>" +
-	"\n<br>\n\n**Warning**: Output length greater than max comment size. Continued in next comment."
-
-// detailsOpen is prepended to the following comments when we split.
-const detailsOpen = "Continued from previous comment.\n<details><summary>Show Output</summary>\n\n" +
-	"```diff\n"
-
-// maxCommentBodySize is derived from the error message when you go over
-// this limit.
-// We deduct some characters for appending details close/open tag
-const maxCommentBodySize = 65536 - len(detailsClose) - len(detailsOpen)
+// maxCommentLength is the maximum number of chars allowed in a single comment
+// by GitHub.
+const maxCommentLength = 65536
 
 // GithubClient is used to perform GitHub actions.
 type GithubClient struct {
@@ -101,7 +92,12 @@ func (g *GithubClient) GetModifiedFiles(repo models.Repo, pull models.PullReques
 // If comment length is greater than the max comment length we split into
 // multiple comments.
 func (g *GithubClient) CreateComment(repo models.Repo, pullNum int, comment string) error {
-	comments := g.splitAtMaxChars(comment, maxCommentBodySize)
+	sepEnd := "\n```\n</details>" +
+		"\n<br>\n\n**Warning**: Output length greater than max comment size. Continued in next comment."
+	sepStart := "Continued from previous comment.\n<details><summary>Show Output</summary>\n\n" +
+		"```diff\n"
+
+	comments := common.SplitComment(comment, maxCommentLength, sepEnd, sepStart)
 	for _, c := range comments {
 		_, _, err := g.client.Issues.CreateComment(g.ctx, repo.Owner, repo.Name, pullNum, &github.IssueComment{Body: &c})
 		if err != nil {
@@ -151,35 +147,3 @@ func (g *GithubClient) UpdateStatus(repo models.Repo, pull models.PullRequest, s
 	_, _, err := g.client.Repositories.CreateStatus(g.ctx, repo.Owner, repo.Name, pull.HeadCommit, status)
 	return err
 }
-
-// splitAtMaxChars splits comment into a slice with string up to max
-// len separated by join which gets appended to the ends of the middle strings.
-// nolint: unparam
-func (g *GithubClient) splitAtMaxChars(comment string, maxSize int) []string {
-	// If we're under the limit then no need to split.
-	if len(comment) <= maxSize {
-		return []string{comment}
-	}
-
-	var comments []string
-	numComments := int(math.Ceil(float64(len(comment)) / float64(maxSize)))
-	for i := 0; i < numComments; i++ {
-		upTo := g.min(len(comment), (i+1)*maxSize)
-		portion := comment[i*maxSize : upTo]
-		if i < numComments-1 {
-			portion += detailsClose
-		}
-		if i > 0 {
-			portion = detailsOpen + portion
-		}
-		comments = append(comments, portion)
-	}
-	return comments
-}
-
-func (g *GithubClient) min(a, b int) int {
-	if a < b {
-		return a
-	}
-	return b
-}

server/events/vcs/github_client_internal_test.go

@@ -19,35 +19,6 @@ import (
 	. "github.com/runatlantis/atlantis/testing"
 )
 
-// If under the maximum number of chars, we shouldn't split the comments.
-func TestSplitAtMaxChars_UnderMax(t *testing.T) {
-	client := &GithubClient{}
-	comment := "comment under max size"
-	split := client.splitAtMaxChars(comment, len(comment)+1)
-	Equals(t, []string{comment}, split)
-}
-
-// If the comment is over the max number of chars, we should split it into
-// multiple comments.
-func TestSplitAtMaxChars_OverMaxOnce(t *testing.T) {
-	client := &GithubClient{}
-	comment := "comment over max size"
-	split := client.splitAtMaxChars(comment, len(comment)-1)
-	Equals(t, []string{"comment over max siz" + detailsClose, detailsOpen + "e"}, split)
-}
-
-// Test that it works for multiple comments.
-func TestSplitAtMaxChars_OverMaxMultiple(t *testing.T) {
-	client := &GithubClient{}
-	comment := "comment over max size"
-	third := len(comment) / 3
-	split := client.splitAtMaxChars(comment, third)
-	Equals(t, []string{
-		comment[:third] + detailsClose,
-		detailsOpen + comment[third:third*2] + detailsClose,
-		detailsOpen + comment[third*2:]}, split)
-}
-
 // If the hostname is github.com, should use normal BaseURL.
 func TestNewGithubClient_GithubCom(t *testing.T) {
 	client, err := NewGithubClient("github.com", "user", "pass")