Script to periodically fetch and merge upstream changes

.gitignore

+node_modules/
+work/

README.md

+# Script to periodically fetch and merge upstream changes
+
+The use case is to keep a **project** repository up to date with changes from **upstream** repository.
+
+This basically runs in a loop
+
+```
+git fetch project
+git reset --hard project/master
+git fetch upstream
+git merge upstream/master
+git push project master
+```
+## Install
+
+Needs nodejs >= 16
+```
+npm install
+```
+
+## Usage
+
+```
+cp config-example.yaml config.yaml
+$EDITOR config.yaml
+npx run zx autogitmerge.mjs
+```
+ 
\ No newline at end of file

autogitmerge.mjs

+#!/usr/bin/env zx
+import 'zx/globals'
+
+const configData = await fs.readFile(argv['config'] || './config.yaml', 'utf-8')
+const config = YAML.parse(configData)
+const wd = config['working-directory'] || 'work';
+const interval = (config.interval || (15 * 60)) * 1000;
+
+if (!fs.existsSync(wd)) {
+  echo(`Initializing ${wd}`)
+  await $`mkdir ${wd}`
+  cd(wd)
+  await $`git init`
+  await $`git remote add upstream ${config.upstream.url}`
+  await $`git remote add project ${config.project.url}`
+  await $`git fetch --all`
+  await $`git checkout -b ${config.project.branch} project/${config.project.branch}`
+  if (config.committer !== undefined) {
+    await $`git config user.name ${config.committer.name}`
+    await $`git config user.email ${config.committer.email}`
+  }
+  cd('..')
+}
+
+cd(wd)
+let fetchErrors = 0, reportedConflictHashes
+while (true) {
+  try {
+    await $`git fetch --all`
+  } catch (e) {
+    echo('Error fetching')
+    fetchErrors++
+    if (fetchErrors > 10) {
+      throw e
+    }
+    await sleep(interval)
+  }
+
+  fetchErrors = 0
+  await $`git reset --hard project/${config.project.branch}`
+  let mergeSuccess = true;
+  try {
+    await $`git merge upstream/${config.upstream.branch}`
+  } catch (e) {
+    mergeSuccess = false;
+    const currentHashes = (
+      (await $`git rev-parse --short project/${config.project.branch}`).stdout.trim()
+      + ' and '
+      + (await $`git rev-parse --short upstream/${config.upstream.branch}`).stdout.trim()
+    )
+    echo(chalk.red(`😱  could not merge master ${currentHashes}`))
+    if (currentHashes !== reportedConflictHashes) {
+      /** we saw this conflict for the first time, notify */
+      reportedConflictHashes = currentHashes
+      if (config?.notification?.type === 'comment-on-gitlab-merge-request') {
+        const url = new URL(config.notification['merge-request-url']);
+        let [projectId, mergeRequestIid] = url.pathname.substring(1).split('/merge_requests/');
+        url.pathname = `/api/v4/projects/${encodeURIComponent(projectId)}/merge_requests/${mergeRequestIid}/notes`
+        console.log(url.toString())
+        let body = config.notification.message
+        if (body === undefined) {
+          // merge again capturing the output this time
+          await $`git reset --hard project/${config.project.branch}`
+          const gitOutput = (await $`git merge upstream/${config.upstream.branch}`.nothrow()).toString()
+          body = `Error while merging upstream changes
+\`\`\`console
+$ git merge upstream/${config.upstream.branch}
+${gitOutput}
+\`\`\`
+        `
+        }
+        const resp = await fetch(
+          url,
+          {
+            method: 'post',
+            body: JSON.stringify({ body }),
+            headers: {
+              'content-type': 'application/json',
+              'PRIVATE-TOKEN': config.notification['gitlab-token'],
+            }
+          })
+        echo(JSON.stringify(await resp.json()))
+      }
+    } else {
+      echo(`conflict already notified`)
+    }
+  }
+  if (mergeSuccess) {
+    await $`git push project ${config.project.branch}`
+  }
+  await sleep(interval)
+}

config-example.yaml

+# yaml-language-server: $schema=config-schema.json
+
+working-directory: ./erp5-zope4py2
+
+upstream:
+  url: https://lab.nexedi.com/nexedi/erp5/
+  branch: master
+
+project:
+  url: https://lab.nexedi.com/nexedi/erp5/
+  branch: zope4py2
+
+interval: 2
+
+# optional: committer for the merge commits
+committer:
+  name: Merge Bot
+  email: gitlab@nexedi.com
+
+# optional: send notification when a conflict occur during merge
+notification:
+  type: comment-on-gitlab-merge-request
+  merge-request-url: https://lab.nexedi.com/nexedi/erp5/merge_requests/1545
+  # a user token, comments will be posted as this user
+  gitlab-token: XXX

config-schema.json

+{
+  "$schema": "http://json-schema.org/draft-07/schema",
+  "additionalProperties": false,
+  "required": [
+    "upstream",
+    "project"
+  ],
+  "definitions": {
+    "repository": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "url": {
+          "type": "string",
+          "description": "URL of the repository",
+          "format": "uri"
+        },
+        "branch": {
+          "type": "string",
+          "description": "Branch in the repository",
+          "default": "master"
+        }
+      }
+    }
+  },
+  "properties": {
+    "working-directory": {
+      "type": "string",
+      "description": "Directory to use for the working copy"
+    },
+    "upstream": {
+      "$ref": "#/definitions/repository",
+      "examples": [
+        {
+          "url": "https://lab.nexedi.com/nexedi/erp5/",
+          "branch": "master"
+        }
+      ]
+    },
+    "project": {
+      "$ref": "#/definitions/repository",
+      "examples": [
+        {
+          "url": "https://lab.nexedi.com/nexedi/project-erp5/",
+          "branch": "next"
+        }
+      ]
+    },
+    "notification": {
+      "oneOf": [
+        {
+          "additionalProperties": false,
+          "type": "object",
+          "required": [
+            "type",
+            "merge-request-url",
+            "gitlab-token"
+          ],
+          "properties": {
+            "type": {
+              "type": "string",
+              "const": "comment-on-gitlab-merge-request",
+              "default": "comment-on-gitlab-merge-request"
+            },
+            "merge-request-url": {
+              "type": "string",
+              "description": "URL of a gitlab merge request to send notifications when not able to merge automatically",
+              "format": "uri"
+            },
+            "gitlab-token": {
+              "type": "string",
+              "description": "gitlab token"
+            },
+            "message":{
+              "type": "string",
+              "description": "Message to body to post instead of the git command output"
+            }
+          }
+        }
+      ]
+    },
+    "committer": {
+      "type": "object",
+      "additionalProperties": false,
+      "default": "taken from global git config",
+      "examples": [
+        {
+          "name": "Merge Bot",
+          "email": "gitlab@nexedi.com"
+        }
+      ],
+      "properties": {
+        "name": {
+          "type": "string",
+          "description": "Name of the author of the merge commits"
+        },
+        "email": {
+          "type": "string",
+          "description": "Email of the author of the merge commits"
+        }
+      }
+    },
+    "interval": {
+      "type": "number",
+      "description": "Interval in seconds between each fetch",
+      "default": 900
+    }
+  }
+}
\ No newline at end of file

package.json

+{
+  "dependencies": {},
+  "devDependencies": {
+    "zx": "^7.0.0"
+  }
+}
\ No newline at end of file