Break each replacement out of the update-content file and provide a system for writing more replacements (#29)

Co-authored-by: Harrison Muskat <hmuskat@6river.com>

Author: 2 people

README.md

@@ -15,10 +15,18 @@ For each repo, this tool will:
 
 ## Installation
 
-```bash
+```shell
 npm install -g github-default-branch
 ```
 
+## Development
+
+```shell
+git clone https://github.com/6RiverSystems/github-default-branch.git
+cd github-default-branch
+npm ci
+```
+
 ## Authentication
 
 [Create a personal access token](https://github.com/settings/tokens/new?scopes=repo&description=github-default-branch) with the `repo` scope. This is the value for `<token>` in the examples.
@@ -58,3 +66,54 @@ Run with the `--verbose` flag to see debug information
 | --old             | The name of the branch to rename                               | master  |
 | --new             | The new branch name                                            | main    |
 | --confirm         | Run without prompting for confirmation                         | false   |
+
+## Replacements
+
+Part of this script checks for the existence of files and updates their contents. Replacements are the mechanism for these updates.
+
+### How it Works
+
+Each .js file in the src/replacements folder is given a chance to run during the content updating step of the script. Each file in src/replacements is expected to export a function, that function receives all of the options that are available to the outmost script.
+
+If there is nothing to replace, then the script moves on to the next replacement.
+
+### How to Add a Replacement
+
+Add a file to src/replacements with a .js extension
+
+Like this:
+
+```javascript
+module.exports = function ({
+    owner, // string - repo owner
+    repo, // string - repo name
+    old, // string - old branch name
+    target, // string - new branch name
+    octokit, // Octokit - oktokit instance
+    verbose, // boolean - verbose flag
+    isDryRun, // boolean - dry run flag
+}) {
+    // code goes here
+    return {
+        path: '<path to file in repo>',
+        replacements: [
+            {
+                from: '<from pattern>',
+                to: '<to pattern>',
+            },
+            {
+                from: '<from pattern>',
+                to: '<to pattern>',
+            },
+        ],
+    };
+}
+
+```
+
+The file with the path in your repo will have any line matching `from` be swapped out with `to`
+
+
+### Known Issues
+
+The replacement system gives you octokit, that's great! Unfortunately replacement functions do not currently support asynchronous calls, that's bad.

bin/github-default-branch

@@ -105,8 +105,9 @@
   const updateContent = require("../src/update-content");
   const updateBranchProtection = require("../src/branch-protection");
 
-  const old = argv.old || "master";
-  const target = argv.new || "main";
+  const old = argv.old;
+  const target = argv.new;
+  const verbose = argv.verbose;
 
   // Make sure they want to do this
   if (!(await confirmation(argv.confirm, old, target))) {
@@ -117,7 +118,7 @@
     auth: argv.pat || process.env.GITHUB_TOKEN,
   });
 
-  if (argv.verbose) {
+  if (verbose) {
     const {
       data: {
         rate: { remaining },
@@ -133,7 +134,7 @@
     return;
   }
   for (let r of repos) {
-    if (argv.verbose) {
+    if (verbose) {
       console.log(`✏️  Processing ${r}`);
     }
 
@@ -148,12 +149,12 @@
       continue;
     }
 
-    if (argv.verbose) {
+    if (verbose) {
       console.log(`✏️  Creating branch [${target}] at [${currentMasterSha}]`);
     }
 
     if (!isDryRun) {
-      const mainBranch = await createBranch(
+      await createBranch(
         owner,
         repo,
         target,
@@ -180,7 +181,7 @@
         continue;
       }
 
-      if (argv.verbose) {
+      if (verbose) {
         console.log(
           `✏️  Updating pull request [#${pr.number}] in [${repo}] from [${pr.base.ref}] to [${target}]`
         );
@@ -196,11 +197,18 @@
       }
     }
 
-    if (argv.verbose) {
+    if (verbose) {
       console.log(`✏️  Updating default branch to [${target}] in [${repo}]`);
     }
 
-    if (!isDryRun) {
+    const {
+      data: { default_branch: defaultBranch },
+    } = await octokit.repos.get({
+      owner,
+      repo
+    });
+
+    if (!isDryRun && defaultBranch === old) {
       // Update the default branch in the repo
       await octokit.repos.update({
         owner,
@@ -209,15 +217,15 @@
       });
     }
 
-    if (argv.verbose) {
+    if (verbose) {
       console.log(`✏️  Changing branch protections`);
     }
 
     if (!isDryRun) {
       await updateBranchProtection(owner, repo, old, target, octokit);
     }
 
-    if (argv.verbose) {
+    if (verbose) {
       console.log(`✏️  Deleting old branch [${old}] in ${repo}`);
     }
 
@@ -229,18 +237,18 @@
     }
 
     // Update all content on the branch
-    await updateContent(
+    await updateContent({
       owner,
       repo,
       old,
       target,
       octokit,
-      argv.verbose,
+      verbose,
       isDryRun
-    );
+    });
 
     // Add an empty new line to break up the output for each repo
-    if (argv.verbose) {
+    if (verbose) {
       console.log("");
     }
   }

src/replacements/circleci.js

@@ -0,0 +1,23 @@
+module.exports = function ({old, target}) {
+    return {
+        path: ".circleci/config.yml",
+        replacements: [
+            {
+                from: `- ${old}`,
+                to: `- ${target}`
+            },
+            {
+                from : `branch: ${old}`,
+                to: `branch: ${target}`
+            },
+            {
+                from: `only: ${old}`,
+                to: `only: ${target}`
+            },
+            {
+                from: `"${old}"`,
+                to: `"${target}"`
+            }
+        ]
+    };
+}

src/replacements/readme.js

@@ -0,0 +1,15 @@
+module.exports = function ({owner, repo, old, target}) {
+    return {
+        path: "README.md",
+        replacements: [
+            {
+                from: `@${old}`,
+                to: `@${target}`,
+            },
+            {
+                from: `${owner}/${repo}.svg?branch=${old}`,
+                to: `${owner}/${repo}.svg?branch=${target}`,
+            },
+        ],
+    };
+}

src/update-content.js

@@ -1,43 +1,39 @@
+const fs = require('fs');
+const util = require('util');
 const replaceAll = require("string.prototype.replaceall");
 
-module.exports = async function (
-  owner,
-  repo,
-  old,
-  target,
-  octokit,
-  isVerbose,
-  isDryRun
-) {
-  const replacements = {
-    "README.md": [
-      {
-        from: `@${old}`,
-        to: `@${target}`,
-      },
-      {
-        from: `${owner}/${repo}.svg?branch=${old}`,
-        to: `${owner}/${repo}.svg?branch=${target}`,
-      },
-    ],
-  };
+const ls = util.promisify(fs.readdir);
 
+module.exports = async function (options) {
+  const {
+    owner,
+    repo,
+    octokit,
+    verbose,
+    isDryRun,
+  } = options;
+  const replacementsDir = `${__dirname}/replacements`;
+  const files = (await ls(replacementsDir)).filter((f) => f.endsWith('.js'));
+  const replacements = files.reduce((acc, next) => {
+    const { path, replacements } = require(`${replacementsDir}/${next}`)(options);
+    return Object.assign(acc, { [path]: replacements });
+  }, {});
   for (let path in replacements) {
     try {
       let file = await loadFile(owner, repo, path, octokit);
 
       let content = file.content;
       for (let r of replacements[path]) {
-        var re = new RegExp(r.from, "g");
-        content = replaceAll(content, r.from, r.to);
+        const re = new RegExp(r.from, "g");
+        content = replaceAll(content, re, r.to);
       }
 
       if (content !== file.content) {
-        if (isVerbose) {
+        if (verbose) {
           console.log(`✏️  Updating [${path}]`);
         }
         if (!isDryRun) {
-          const r = await writeFile(
+          await writeFile(
             owner,
             repo,
             path,
@@ -47,12 +43,12 @@ module.exports = async function (
           );
         }
       } else {
-        if (isVerbose) {
+        if (verbose) {
           console.log(`✏️  No changes detected in [${path}]`);
         }
       }
     } catch (e) {
-      if (isVerbose) {
+      if (verbose) {
         console.log(`✏️  Unable to update [${path}]`);
       }
     }