[syncer] add dry run mode

[capcom6]

Summary by CodeRabbit

• New Features

  • Added a --dry-run option to preview sync operations; file events are reported as "Would create/modify/remove" without making changes.

• Improvements

  • Consistent path logging across sync events.
  • Upload logs now include file sizes when available for clearer transfer visibility.

[github-actions]

🤖 Pull request artifacts

Platform	File
🐳 Docker	GitHub Container Registry
🍎 Darwin arm64	sftp-sync_Darwin_arm64.tar.gz
🍎 Darwin x86_64	sftp-sync_Darwin_x86_64.tar.gz
🐧 Linux arm64	sftp-sync_Linux_arm64.tar.gz
🐧 Linux i386	sftp-sync_Linux_i386.tar.gz
🐧 Linux x86_64	sftp-sync_Linux_x86_64.tar.gz
🪟 Windows arm64	sftp-sync_Windows_arm64.zip
🪟 Windows i386	sftp-sync_Windows_i386.zip
🪟 Windows x86_64	sftp-sync_Windows_x86_64.zip

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 752aaba5-531f-4544-896c-ae2f1bee20c3

📥 Commits

Reviewing files that changed from the base of the PR and between a49f9a2 and ad23110.

📒 Files selected for processing (4)

• internal/cli/commands/sync/config.go
• internal/cli/commands/sync/sync.go
• internal/syncer/syncer.go
• main.go

🚧 Files skipped from review as they are similar to previous changes (4)

• main.go
• internal/cli/commands/sync/config.go
• internal/syncer/syncer.go
• internal/cli/commands/sync/sync.go

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Walkthrough

Adds a --dry-run CLI flag (global and passed into the sync command). When enabled, watcher events do not invoke the syncer and instead log “Would create/modify/remove ”. Syncer logging is standardized to use a fieldPath key and includes size when os.Stat succeeds.

Changes

Sync CLI + Dry-run + Logging

Layer / File(s)	Summary
Data Shape internal/cli/commands/sync/config.go	config gains a DryRun bool field; parseConfig default-inits and sets it from --dry-run.
CLI Wiring main.go	Adds the --dry-run boolean flag to the sftp-sync command flags.
Control Flow / Dry-run Behavior internal/cli/commands/sync/sync.go	Watcher event loop branches on cfg.DryRun: when true call new dryRunLog(ctx, event) which logs Would <action> with logger.Fields{"path": event.RelPath}; when false call syncer.Sync(ctx, event.AbsPath) as before. Also introduces the unexported dryRunLog helper.
Operational Logging internal/syncer/syncer.go	Introduces fieldPath = "path" constant used consistently in logger.Fields; "Uploaded" log now builds a fields map with fieldPath: relPath and conditionally adds size from os.Stat(absPath) before logging.

Sequence Diagram

sequenceDiagram
    actor Watcher
    participant CLI
    participant Syncer
    participant Logger

    Watcher->>CLI: file event (create/modify/remove, rel+abs path)
    CLI->>CLI: check cfg.DryRun
    alt DryRun == true
        CLI->>Logger: log "Would <action>" with `path` (relPath)
    else DryRun == false
        CLI->>Syncer: Sync(ctx, absPath)
        Syncer->>Syncer: optional os.Stat(absPath) -> size
        Syncer->>Logger: log "Uploaded"/"Created"/"Removed" with `path`[, size]
    end

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title '[syncer] add dry run mode' directly and clearly describes the main change: adding a dry run feature to the syncer component.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch syncer/dry-run-mode

---

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@internal/syncer/syncer.go`:
- Around line 81-84: The call to os.Stat(absPath) in the syncer code can return
an error and leave info nil, so guard the result before calling info.Size():
check the error returned by os.Stat(absPath) (and that info != nil) and handle
the failure path (e.g., log the stat error with s.logger.Error/Info and use a
fallback size like 0 or skip logging size) before invoking info.Size() in the
s.logger.Info call; update the block around os.Stat(absPath), the info variable,
and the s.logger.Info(...) call to avoid a nil dereference.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 4e96bfb8-fdae-4b87-b0d6-bed81879e647

📥 Commits

Reviewing files that changed from the base of the PR and between 5f6bfd6 and dbe9a2e.

📒 Files selected for processing (4)

• internal/cli/commands/sync/config.go
• internal/cli/commands/sync/sync.go
• internal/syncer/syncer.go
• main.go