Trim PR comments from the front.

CHANGELOG.md

@@ -2,7 +2,8 @@
 
 ## HEAD (Unreleased)
 
-_(none)_
+- feat: Trim PR comments from the front
+  ([#1252](https://github.com/pulumi/actions/pull/1252))
 
 ---
 
@@ -311,4 +312,4 @@ _(none)_
 
 ## 2.0.1 (2021-02-26)
 
-- Initial reworking of the Action to be TypeScript based
+- Initial reworking of the Action to be TypeScript based

README.md

@@ -143,12 +143,17 @@ The action can be configured with the following arguments:
 
 - `plan` - (optional) Used for
   [update plans](https://www.pulumi.com/docs/concepts/update-plans/)
+
   - On `preview`: Where to save the update plan. If you choose to use this in a
     different run of your workflow (let's say you create an update plan via a
     preview on Pull Request creation and want to `up` using the plan) you must
     upload the plan as an artifact, and retrieve it wherever you run `up`
   - On `up`: Where to read the update plan from.
 
+- `trim-comments-from-front` - (optional) If `true`, then the action will trim
+  long pr comments from the front instead of the back. This ensures that the
+  resources summary is always visible.
+
 By default, this action will try to authenticate Pulumi with
 [Pulumi Cloud](https://app.pulumi.com/). If you have not specified a
 `PULUMI_ACCESS_TOKEN` then you will need to specify an alternative backend via

action.yml

@@ -110,6 +110,10 @@ inputs:
     description: 'Suppress display of periodic progress dots to limit logs length'
     required: false
     default: 'false'
+  trim-comments-from-front:
+    description: 'If comments must be trimmed, trim them from the front. This ensures the resources summary is included in the comment'
+    required: false
+    default: 'false'
 outputs:
   output:
     description: Output from running command

src/__tests__/config.test.ts

@@ -9,6 +9,7 @@ const defaultConfig: Record<string, string> = {
   'pulumi-version': '^3',
   'comment-on-pr': 'false',
   'comment-on-summary': 'false',
+  'trim-comments-from-front': 'false',
   upsert: 'false',
   remove: 'false',
   refresh: 'false',
@@ -69,6 +70,7 @@ describe('config.ts', () => {
         "remove": false,
         "secretsProvider": "",
         "stackName": "dev",
+        "trimCommentsFromFront": false,
         "upsert": false,
         "workDir": "./",
       }

src/config.ts

@@ -92,6 +92,7 @@ export function makeConfig() {
     // @see https://github.com/pulumi/actions/pull/912
     configMap: getYAMLInput<ConfigMap>('config-map'),
     editCommentOnPr: getBooleanInput('edit-pr-comment'),
+    trimCommentsFromFront: getBooleanInput('trim-comments-from-front'),
 
     options: {
       parallel: getNumberInput('parallel', {}),

src/libs/__tests__/pr.test.ts

@@ -50,7 +50,7 @@ describe('pr.ts', () => {
 
     await handlePullRequestMessage(defaultOptions, projectName, 'test');
     expect(createComment).toHaveBeenCalledWith({
-      body: '#### :tropical_drink: `preview` on myFirstProject/staging\n\n<details>\n<summary>Pulumi report</summary>\n\n<pre>\ntest\n</pre>\n\n</details>',
+      body: '#### :tropical_drink: `preview` on myFirstProject/staging\n\n<details>\n<summary>Pulumi report</summary>\n\n\n<pre>\ntest\n</pre>\n\n</details>',
       issue_number: 123,
     });
   });
@@ -69,7 +69,7 @@ describe('pr.ts', () => {
 
     await handlePullRequestMessage(defaultOptions, projectName, '\x1b[30mblack\x1b[37mwhite');
     expect(createComment).toHaveBeenCalledWith({
-      body: '#### :tropical_drink: `preview` on myFirstProject/staging\n\n<details>\n<summary>Pulumi report</summary>\n\n<pre>\n<span style="color:#000">black<span style="color:#AAA">white</span></span>\n</pre>\n\n</details>',
+      body: '#### :tropical_drink: `preview` on myFirstProject/staging\n\n<details>\n<summary>Pulumi report</summary>\n\n\n<pre>\n<span style="color:#000">black<span style="color:#AAA">white</span></span>\n</pre>\n\n</details>',
       issue_number: 123,
     });
   });
@@ -93,7 +93,7 @@ describe('pr.ts', () => {
 
     await handlePullRequestMessage(options, projectName, 'test');
     expect(createComment).toHaveBeenCalledWith({
-      body: '#### :tropical_drink: `preview` on myFirstProject/staging\n\n<details>\n<summary>Pulumi report</summary>\n\n<pre>\ntest\n</pre>\n\n</details>',
+      body: '#### :tropical_drink: `preview` on myFirstProject/staging\n\n<details>\n<summary>Pulumi report</summary>\n\n\n<pre>\ntest\n</pre>\n\n</details>',
       issue_number: 87,
     });
   });
@@ -120,7 +120,7 @@ describe('pr.ts', () => {
 
     await handlePullRequestMessage(options, projectName, 'test');
     expect(createComment).toHaveBeenCalledWith({
-      body: '#### :tropical_drink: `preview` on myFirstProject/staging\n\n<details>\n<summary>Pulumi report</summary>\n\n<pre>\ntest\n</pre>\n\n</details>',
+      body: '#### :tropical_drink: `preview` on myFirstProject/staging\n\n<details>\n<summary>Pulumi report</summary>\n\n\n<pre>\ntest\n</pre>\n\n</details>',
       issue_number: 87,
     });
   });
@@ -144,7 +144,38 @@ describe('pr.ts', () => {
 
     const call = createComment.mock.calls[0][0];
     expect(call.body.length).toBeLessThan(65_536);
-    expect(call.body).toContain('The output was too long and trimmed');
+    expect(call.body).toContain('The output was too long and trimmed.');
+    expect(call.body).not.toContain('The output was too long and trimmed from the front.');
+  });
+
+  it('should trim the output from front when the output is larger than 64k characters and config is set', async () => {
+    process.env.GITHUB_REPOSITORY = 'pulumi/actions';
+    // @ts-ignore
+    gh.context = {
+      payload: {
+        pull_request: {
+          number: 123,
+        },
+      },
+    };
+    const trimFromFrontOptions = {
+      command: 'preview',
+      stackName: 'staging',
+      trimCommentsFromFront: true,
+      options: {},
+    } as Config;
+
+    await handlePullRequestMessage(
+      trimFromFrontOptions,
+      projectName,
+      'a'.repeat(65_000) + '\n' + 'this is at the end and should be in the output',
+    );
+
+    const call = createComment.mock.calls[0][0];
+    expect(call.body.length).toBeLessThan(65_536);
+    expect(call.body).toContain('this is at the end and should be in the output');
+    expect(call.body).toContain('The output was too long and trimmed from the front.');
+    expect(call.body).not.toContain('The output was too long and trimmed.');
   });
 
   it('should edit the comment if it finds a previous created one', async () => {
@@ -161,7 +192,7 @@ describe('pr.ts', () => {
     await handlePullRequestMessage(options, projectName, 'test');
     expect(updateComment).toHaveBeenCalledWith({
       comment_id: 2,
-      body: '#### :tropical_drink: `preview` on myFirstProject/staging\n\n<details>\n<summary>Pulumi report</summary>\n\n<pre>\ntest\n</pre>\n\n</details>',
+      body: '#### :tropical_drink: `preview` on myFirstProject/staging\n\n<details>\n<summary>Pulumi report</summary>\n\n\n<pre>\ntest\n</pre>\n\n</details>',
     });
   });
 });

src/libs/pr.ts

@@ -8,11 +8,13 @@ import { Config } from '../config';
 function ansiToHtml(
   message: string,
   maxLength: number,
+  trimCommentsFromFront: boolean,
 ): [string, boolean] {
   /**
    *  Converts an ansi string to html by for example removing color escape characters.
    *  message: ansi string to convert
    *  maxLength: Maximum number of characters of final message incl. HTML tags
+   *  trimCommentsFromFront: if true, trim message from front (if trimming is needed), otherwise from end
    *
    *  return message as html and information if message was trimmed because of length
    */
@@ -24,9 +26,15 @@ function ansiToHtml(
   // Check if htmlBody exceeds max characters
   if (htmlBody.length > maxLength) {
 
-    // trim input message by number of exceeded characters
+    // trim input message by number of exceeded characters from front or back as configured
     const dif: number = htmlBody.length - maxLength;
-    message = message.substring(0, message.length - dif);
+
+    if (trimCommentsFromFront) {
+      message = message.substring(dif, htmlBody.length);
+    } else {
+      message = message.substring(0, message.length - dif);
+    }
+
     trimmed = true;
 
     // convert trimmed message to html
@@ -46,6 +54,7 @@ export async function handlePullRequestMessage(
     command,
     stackName,
     editCommentOnPr,
+    trimCommentsFromFront,
   } = config;
 
   // GitHub limits comment characters to 65535, use lower max to keep buffer for variable values
@@ -55,21 +64,24 @@ export async function handlePullRequestMessage(
 
   const summary = '<summary>Pulumi report</summary>';
 
-  const [htmlBody, trimmed]: [string, boolean] = ansiToHtml(output, MAX_CHARACTER_COMMENT);
+  const [htmlBody, trimmed]: [string, boolean] = ansiToHtml(output, MAX_CHARACTER_COMMENT, trimCommentsFromFront);
 
   const body = dedent`
     ${heading}
 
     <details>
     ${summary}
 
+    ${trimCommentsFromFront
+      ? ':warning: **Warn**: The output was too long and trimmed from the front.'
+      : ''
+    }
     <pre>
     ${htmlBody}
     </pre>
-    ${
-      trimmed
-        ? ':warning: **Warn**: The output was too long and trimmed.'
-        : ''
+    ${trimmed && !trimCommentsFromFront
+      ? ':warning: **Warn**: The output was too long and trimmed.'
+      : ''
     }
     </details>
   `;