Source: Dev.to

The Problem: Deploy Scripts Fail and You Start Over

You’re running a 50‑step deploy process. Step 47 fails. You’ve already provisioned infrastructure, pulled images, run migrations, seeded data. Now you have two options:

• Start over from step 1 – 45 minutes wasted.
• Try to manually re‑run from where it failed – good luck remembering what you already ran.

Neither is great. What if you could rewind to step 45 and try a different path, like hitting Ctrl+Z in your terminal?

That’s what devops-rewind does.

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3 Lines to Get Started

pip install devops-rewind
devops-rewind record my-deploy
devops-rewind rewind my-deploy 45

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How It Works

Record a session:                  When it fails:
┌──────────────────────┐          ┌──────────────────────┐
│ [0] git pull      OK │          │ rewind to step 1     │
│ [1] make build    OK │──────────│ branch from step 1   │
│ [2] make test     OK │          │ try new commands      │
│ [3] make deploy FAIL │          │ diff original vs fix │
└──────────────────────┘          └──────────────────────┘

devops-rewind records every command you run — the command itself, stdout/stderr, exit code, working directory, and timestamp. Each command is a numbered step. When something fails, you can rewind to any step, inspect the exact state, or branch off to try a different approach.

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Core Features

Record

Start a recording session with a named identifier:

devops-rewind record my-deploy

The CLI opens an interactive prompt where every command you run is captured:

[0] /app $ git pull
Already up to date.
[1] /app $ make build
Building...
[2] /app $ make deploy
Error: connection refused
[3] /app $ exit
Session saved: my-deploy (3 steps)

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Rewind

Jump to any step and see exactly what happened:

devops-rewind rewind my-deploy 2

The output shows the command, its output, the working directory at that point, and a summary of any failures that occurred before or after.

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Breakpoints

Set breakpoints that pause replay at specific conditions:

# Break at step 47
devops-rewind breakpoint add my-deploy 47

# Break on any kubectl command
devops-rewind breakpoint add my-deploy --pattern "kubectl apply"

# Break on any non‑zero exit code
devops-rewind breakpoint add my-deploy --on-error

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Branch

Fork a session from any step. The new branch inherits all history up to that point:

devops-rewind branch my-deploy 1 --exec

You are now in a new recording session with steps 0 and 1 already in history. Run different commands from there.

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Diff

Compare two sessions side‑by‑side. The diff engine finds the exact step where they diverge:

devops-rewind diff my-deploy my-deploy-branch-1

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Export

Turn any session into a runnable script, markdown document, or JSON:

devops-rewind export my-deploy --format sh > deploy.sh

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Why Not Just Use script or asciinema?

script and asciinema record raw terminal output. They don’t understand individual commands, exit codes, or state. devops-rewind records at the command level, which enables rewind, branching, and diffing.

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Architecture

src/devops_rewind/
├── cli.py           # Click CLI with 8 commands
├── recorder.py      # Command‑by‑command recording via subprocess
├── session.py       # Step + Session dataclasses
├── player.py        # Replay + rewind engine
├── breakpoints.py   # Step/pattern/error breakpoint types
├── branching.py     # Fork session from any step
├── differ.py        # Diverge‑point detection + diff
├── storage.py       # SQLite at ~/.devops-rewind/sessions.db
└── display.py       # Rich panels, tables, side‑by‑side columns

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Recording Approach

I chose subprocess.run() per command instead of wrapping a PTY. This is less “realistic” (no interactive prompts inside recorded commands), but it’s:

• Safe – each command is isolated, no shell‑injection risk
• Testable – easy to mock in unit tests
• Portable – works on macOS, Linux, and Windows
• Structured – you get clean stdout, stderr, and exit code per step

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Branching Implementation

The branching engine copies steps 0 through N from the parent session into a new Session object, then opens a new recorder from that point. The parent session is never modified.

def branch_session(session, from_step, storage, name=None):
    steps = session.steps[: from_step + 1]
    branch = Session.new(name or f"{session.name}-branch-{from_step}")
    branch.steps = [step.copy() for step in steps]
    branch.parent_id = session.session_id
    branch.branch_point = from_step
    storage.save(branch)
    return branch

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Numbers

• 116 tests passing – 89 % coverage
• Python 3.9‑3.12 matrix CI
• SQLite for persistent, portable storage

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Real‑World Use Case

Last week I was debugging a Kubernetes deployment. The sequence was:

1. Build Docker image
2. Push to registry
3. Apply Kubernetes manifests
4. … (the rest of the story continues in the full documentation)

devops-rewind let me rewind to the exact step where the kubectl apply failed, branch off with a corrected manifest, and re‑run only the necessary commands—saving me more than an hour of manual back‑tracking.

ConfigMap

• Apply Deployment
• Wait for rollout

Run smoke test — FAILED

With devops‑rewind, I recorded the whole process, rewound to step 3, branched, and tried a different ConfigMap. The diff clearly showed that one environment variable was wrong. I fixed it, exported the successful branch as a shell script, and added it to CI.

Total time saved: about 30 minutes of re‑running steps 1‑5.

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Try It

pip install devops-rewind
devops-rewind record my-session

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⭐️ Star it on GitHub:
github.com/LakshmiSravyaVedantham/devops-rewind

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What’s the longest deploy sequence you’ve had to debug? Drop it in the comments.