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deploy-lock/README.md

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# Deploy Lock
This is a tool to lock a cluster or service, in order to prevent people from deploying changes during test automation or
an infrastructure incident.
## Contents
- [Deploy Lock](#deploy-lock)
- [Contents](#contents)
- [Abstract](#abstract)
- [Deploy Path](#deploy-path)
- [Lock Data](#lock-data)
- [Messaging](#messaging)
- [Example Usage](#example-usage)
- [Prevent a deploy during an automation run](#prevent-a-deploy-during-an-automation-run)
- [Prevent a deploy during a production incident](#prevent-a-deploy-during-a-production-incident)
- [Prevent duplicate deploys of the same service from conflicting](#prevent-duplicate-deploys-of-the-same-service-from-conflicting)
- [Command-line Interface](#command-line-interface)
- [User Options](#user-options)
- [Backend Options](#backend-options)
- [REST API](#rest-api)
- [Endpoints](#endpoints)
## Abstract
### Deploy Path
The path to a service, starting with the cluster and environment: `apps/staging/a/auth-app`.
Components:
- cluster
- env (`account`)
- target
- service (namespace)
- branch (`ref`)
When _locking_ a path, only the full path is locked, not parents.
When _checking_ a path, each segment is checked recursively, so a lock at `apps/staging` will prevent all services
from being deployed into both the A and B clusters.
- cluster comes first because that is how we structure the git repositories (repo = cluster, branch = env)
- to lock multiple clusters in the same environment, run the command repeatedly with the same lock data
- to lock a specific branch, put it in the path: `apps/staging/a/auth-app/main`
TODO: should the service name (component 3) map to the kubernetes namespace rather than the service?
### Lock Data
Each lock must contain the following fields:
```typescript
interface Lock {
type: 'automation' | 'deploy' | 'incident';
author: string;
links: Map<string, string>;
// Timestamps, calculated from --duration and --until
created_at: number;
updated_at: number;
expires_at: number;
// Env fields
// often duplicates of path, but useful for cross-project locks
env: {
cluster: string;
account: string;
target?: string; // optional
}
// CI fields, optional
ci?: {
project: string;
ref: string;
commit: string;
pipeline: string;
job: string;
}
}
```
Friendly strings for `type`: `An automation run`, `A deploy`, `An incident`.
If `$CI` is not set, the `ci` sub-struct will not be present.
TODO: should there be a `type` for `A release freeze` (`freeze`)?
### Messaging
- create a new lock: 'locked ${path} for ${type:friendly} until ${expires_at:datetime}'
- > Locked `apps/acceptance/a` for a deploy until Sat 31 Dec, 12:00
- > Locked `gitlab/production` for an incident until Sat 31 Dec, 12:00
- error, existing lock: 'error: ${path} is locked until ${expires_at:datetime} by ${type:friendly} in ${cluster}/${env}'
- > Error: `apps/acceptance` is locked until Sat 31 Dec, 12:00 by an automation run in `testing/staging`.
### Example Usage
#### Prevent a deploy during an automation run
This would be used to prevent an application deploy during a test automation run, to make sure the application does not
restart or change versions and invalidate the test results.
1. QA starts an automation run
1. Automation calls `deploy-lock lock apps/acceptance --type automation --duration 90m`
2. Someone merges code into `develop` of `saas-app`
1. The `saas-app` pipeline runs a deploy job
2. The deploy job calls `deploy-lock check apps/acceptance/a/saas-app/develop`, which recursively checks:
1. `apps`
2. `apps/acceptance`
1. locked by automation, exit with an error
3. `apps/acceptance/a`
4. `apps/acceptance/a/saas-app`
5. `apps/acceptance/a/saas-app/develop`
3. Deploy job exits with an error, _does not_ deploy
3. Automation pipeline ends
1. Final job calls `deploy-lock unlock apps/acceptance --type automation`
1. Specifying the `--type` during `unlock` prevents automation/deploy jobs from accidentally removing an incident
2. If the final automation job does not run, the lock will still expire after 90 minutes (`--duration`)
4. Retry `saas-app` deploy job
1. No lock, runs normally
#### Prevent a deploy during a production incident
This would be used to prevent an application deploy during an infrastructure outage, to make sure existing pods
continue running.
1. DevOps receives an alert and declares an incident for the `apps/production/a` cluster
2. The first responder runs `deploy-lock lock apps/production --type incident --duration 6h`
1. This locks _both_ production clusters while we shift traffic to the working one
3. Someone merges code into `main` of `auth-app`
1. The `auth-app` pipeline runs a deploy job
2. The deploy job calls `deploy-lock check apps/production/a/auth-app`, which recursively checks:
1. `apps`
2. `apps/production`
1. locked by incident, exit with an error
3. `apps/production/a`
4. `apps/production/a/auth-app`
3. Deploy job exits with an error, _does not_ deploy
4. Incident is resolved
1. First responder runs `deploy-lock unlock apps/production --type incident`
5. Retry `auth-app` deploy job
1. No lock, runs normally
#### Prevent duplicate deploys of the same service from conflicting
This would be used to prevent multiple simultaneous deploys of the same project from conflicting with one another, in
a service without ephemeral environments/branch switching.
1. Someone starts a pipeline on `feature/foo` of `chat-app`
1. The `chat-app` pipeline runs a deploy job
2. The deploy job calls `deploy-lock lock apps/staging/a/chat-app`
2. Someone else starts a pipeline on `feature/bar` of `chat-app`
1. The `chat-app` pipeline runs another deploy job
1. The first one has not finished and is still mid-rollout
2. The second deploy job calls `deploy-lock lock apps/staging/a/chat-app`, which recursively checks:
1. `apps`
2. `apps/staging`
3. `apps/staging/a`
4. `apps/staging/a/chat-app`
1. locked by deploy, exit with an error
5. `lock` implies `check`
3. Second deploy job fails with an error, _does not_ deploy
3. First deploy succeeds
1. Deploy job calls `deploy-lock unlock apps/staging/a/chat-app`
4. Second deploy job can be retried
1. No lock, runs normally
### Command-line Interface
```shell
> deploy-lock lock --path apps/staging --type automation --duration 60m
> deploy-lock lock --path apps/staging/a/auth-app --type deploy --duration 5m
> deploy-lock lock --path apps/staging --until 2022-12-31T12:00 # local TZ, unless Z specified
> deploy-lock unlock --path apps/staging --type automation # unlock type must match lock type
> deploy-lock check --path apps/staging/a/auth-app # is equivalent to
> deploy-lock check --path apps/staging --path apps/staging/a --path apps/staging/a/auth-app
> deploy-lock check --path apps/staging/a/auth-app --recursive=false # only checks the leaf node
> deploy-lock prune --path apps/staging # prune expired locks within the path
```
#### User Options
- `--type`
- string, enum
- type of lock
- one of `automation`, `deploy`, or `incident`
- `--path`
- array, strings
- record paths
- always lowercase (force in code)
- `/^[-a-z\/]+$/`
- `--author`
- string
- defaults to `$GITLAB_USER_EMAIL` if `$GITLAB_CI` is set
- defaults to `$USER` otherwise
- `--duration`
- number
- duration of lock, relative to now
- mutually exclusive with `--until`
- `--until`
- string, timestamp
- duration of lock, absolute
- mutually exclusive with `--duration`
- `--recursive`
- boolean
- recursively check locks
- defaults to true for `check`
- defaults to false for `lock`, `unlock`
- `--env-cluster`
- string, enum
- defaults to `$CLUSTER_NAME` if set
- defaults to `--path.split.0` otherwise
- `--env-account`
- string, enum
- defaults to `$DEPLOY_ENV` if set
- defaults to `--path.split.1` otherwise
- `--env-target`
- optional string
- `/^[a-z]$/`
- defaults to `$DEPLOY_TARGET` if set
- defaults to `--path.split.2` otherwise
- `--ci-project`
- optional string
- project path
- defaults to `$CI_PROJECT_PATH` if set
- defaults to `--path.split.3` otherwise
- `--ci-ref`
- optional string
- branch or tag
- defaults to `$CI_COMMIT_REF_SLUG` if set
- defaults to `--path.split.4` otherwise
- `--ci-commit`
- optional string
- SHA of ref
- defaults to `$CI_COMMIT_SHA` if set
- `--ci-pipeline`
- optional string
- pipeline ID
- defaults to `$CI_PIPELINE_ID` if set
- `--ci-job`
- optional string
- job ID
- defaults to `$CI_JOB_ID` if set
TODO: should there be an `update` or `replace` command?
TODO: should `--recursive` be available for `lock` or only `unlock`? A recursive lock would write multiple records
#### Backend Options
- `--storage`
- string
- one of `dynamodb`, `memory`
- `--table`
- string
- DynamoDB table name
### REST API
#### Endpoints
- `/locks GET`
- `/locks POST`
- `/locks/:path GET`?