feat: Add cron resource

docs/resources/(resources)/cron.mdx

@@ -0,0 +1,62 @@
+---
+title: cron
+description: A reference page for the cron resource
+---
+
+The cron resource manages scheduled jobs in the current user's crontab using the built-in `crontab` command. It works the same way on macOS and Linux.
+
+Each managed job is written to the crontab as a comment marker followed by the schedule and command:
+
+```sh title="crontab -l"
+# Codify managed: <name>
+<schedule> <command>
+```
+
+The marker comment is how Codify identifies, updates, and removes jobs without disturbing any other entries already in your crontab.
+
+## Parameters
+
+- **jobs**: *(array[object], optional)* An array of cron job definitions. Each job object contains:
+  - **name**: *(string, required)* A unique name identifying this cron job. Used to track the job across runs.
+  - **schedule**: *(string, required)* A cron schedule expression (e.g. `"0 5 * * *"`) or a special schedule string (`@reboot`, `@yearly`, `@monthly`, `@weekly`, `@daily`, `@hourly`).
+  - **command**: *(string, required)* The command to run on the configured schedule.
+
+- **declarationsOnly**: *(boolean, optional)* Controls whether the resource operates in declarative or stateful mode. Defaults to `true`.
+  - `true` (default): Declarative mode — only manages the jobs explicitly listed in the configuration. Other Codify-managed jobs in the crontab (e.g. ones declared elsewhere) are left untouched.
+  - `false`: Stateful mode — Codify tracks and manages all Codify-managed jobs found in the crontab.
+
+## Example usage
+
+### Nightly backup job
+
+```json title="codify.jsonc"
+[
+  {
+    "type": "cron",
+    "jobs": [
+      { "name": "nightly-backup", "schedule": "30 2 * * *", "command": "/usr/local/bin/backup.sh" }
+    ]
+  }
+]
+```
+
+### Multiple maintenance jobs
+
+```json title="codify.jsonc"
+[
+  {
+    "type": "cron",
+    "jobs": [
+      { "name": "health-check", "schedule": "*/5 * * * *", "command": "curl -fsS https://example.com/health" },
+      { "name": "weekly-cleanup", "schedule": "0 3 * * 0", "command": "rm -rf /tmp/myapp-cache/*" }
+    ]
+  }
+]
+```
+
+## Notes
+
+- No installation is required — `cron`/`crontab` ships with both macOS and Linux.
+- This resource manages the **current user's** crontab (`crontab -l` / `crontab <file>`), not system-wide crontabs (e.g. `/etc/crontab` or `/etc/cron.d`).
+- Only entries with the `# Codify managed: <name>` marker are considered — manually added crontab entries are never modified or removed.
+- When a job's `schedule` or `command` changes, Codify removes the old entry and writes a new one in its place.

src/index.ts

@@ -7,6 +7,7 @@ import { AsdfPluginResource } from './resources/asdf/asdf-plugin.js';
 import { AwsCliResource } from './resources/aws-cli/cli/aws-cli.js';
 import { AwsProfileResource } from './resources/aws-cli/profile/aws-profile.js';
 import { DnfResource } from './resources/dnf/dnf.js';
+import { CronResource } from './resources/cron/cron-resource.js';
 import { GoenvResource } from './resources/go/goenv/goenv.js';
 import { DockerResource } from './resources/docker/docker.js';
 import { EnvFileResource } from './resources/file/env-file/env-file-resource.js';
@@ -67,6 +68,7 @@ runPlugin(Plugin.create(
   'default',
   [
     new GitResource(),
+    new CronResource(),
     new XcodeToolsResource(),
     new PathResource(),
     new AliasResource(),

src/resources/cron/cron-resource.test.ts

@@ -0,0 +1,61 @@
+import { describe, expect, it } from 'vitest';
+import { parseManagedJobs, removeJobBlock } from './cron-resource.js';
+
+describe('CronResource unit tests', () => {
+  it('parses a single managed job', () => {
+    const result = parseManagedJobs('# Codify managed: my-job\n*/5 * * * * echo hello\n');
+    expect(result).toMatchObject([{ name: 'my-job', schedule: '*/5 * * * *', command: 'echo hello' }]);
+  });
+
+  it('parses a job with an @special schedule', () => {
+    const result = parseManagedJobs('# Codify managed: daily-job\n@daily echo hello\n');
+    expect(result).toMatchObject([{ name: 'daily-job', schedule: '@daily', command: 'echo hello' }]);
+  });
+
+  it('parses multiple managed jobs', () => {
+    const result = parseManagedJobs(`
+# Codify managed: job-one
+0 5 * * * /usr/local/bin/backup.sh
+
+# Codify managed: job-two
+*/10 * * * * /usr/local/bin/healthcheck.sh
+`);
+    expect(result).toMatchObject([
+      { name: 'job-one', schedule: '0 5 * * *', command: '/usr/local/bin/backup.sh' },
+      { name: 'job-two', schedule: '*/10 * * * *', command: '/usr/local/bin/healthcheck.sh' },
+    ]);
+  });
+
+  it('ignores unmanaged crontab entries', () => {
+    const result = parseManagedJobs(`
+# A manual job, not managed by Codify
+0 0 * * * /usr/local/bin/manual.sh
+
+# Codify managed: managed-job
+0 1 * * * /usr/local/bin/managed.sh
+`);
+    expect(result).toMatchObject([{ name: 'managed-job', schedule: '0 1 * * *', command: '/usr/local/bin/managed.sh' }]);
+  });
+
+  it('removes a managed job block by name', () => {
+    const content = `0 0 * * * /usr/local/bin/manual.sh
+# Codify managed: job-one
+0 5 * * * /usr/local/bin/backup.sh
+# Codify managed: job-two
+*/10 * * * * /usr/local/bin/healthcheck.sh`;
+
+    const result = removeJobBlock(content, 'job-one');
+
+    expect(result).to.not.include('job-one');
+    expect(result).to.not.include('/usr/local/bin/backup.sh');
+    expect(result).to.include('# Codify managed: job-two');
+    expect(result).to.include('/usr/local/bin/healthcheck.sh');
+    expect(result).to.include('/usr/local/bin/manual.sh');
+  });
+
+  it('removeJobBlock is a no-op when the job is not present', () => {
+    const content = '# Codify managed: job-two\n*/10 * * * * /usr/local/bin/healthcheck.sh';
+    const result = removeJobBlock(content, 'job-one');
+    expect(result).toBe(content);
+  });
+});