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overcast local AWS emulator

ECR operations

Every ECR operation Overcast declares — 22 of 25 implemented — with status, behaviour notes and a link to the AWS API reference for each.

22 of 25 listed operations are implemented. Back to ECR.

Summary

Category	✅ Supported	🧊 Inert	⚠️ Partial	❌ Unsupported
General	2		3
Auth			1
Images	3	2	2	3
Policy	6
Tags	3

Endpoints

General

Operation	Status	Notes	AWS Docs
`CreateRepository`	⚠️ Partial	Returns ARN, URI, createdAt, imageTagMutability, imageScanningConfiguration, and encryptionConfiguration; repositoryUri and push readiness depend on a reachable Docker daemon — without one, repositoryUri falls back to Overcast’s own API port and the response carries the emulation-limitation header (`docker push` there answers 405)	docs
`DescribeRepositories`	⚠️ Partial	Lists all repos or filters by name; repositoryUri is re-minted from the currently running registry on every read, so it reflects the same Docker-availability fallback as CreateRepository	docs
`DeleteRepository`	⚠️ Partial	Deletes the repository and all its image records; a repository still holding images raises RepositoryNotEmptyException unless `force` is set. The not-empty check and the echoed repositoryUri both depend on the registry: an unreachable registry falls back to the store’s own image records rather than refusing the delete	docs
`DescribeRegistry`	✅ Supported	Returns registry metadata with empty replication rules	docs
`PutImageTagMutability`	✅ Supported	Stores MUTABLE/IMMUTABLE and DescribeRepositories echoes it; not enforced against a repeat PutImage of the same tag	docs

Auth

Operation	Status	Notes	AWS Docs
`GetAuthorizationToken`	⚠️ Partial	Returns `base64("AWS:<password>")` and the registry proxy endpoint; token expiry is 12 hours. Without a reachable Docker daemon no registry ever starts, so proxyEndpoint falls back to Overcast’s own API port and the token authenticates nothing there — `docker login` succeeds but a subsequent push/pull answers 405	docs

Images

Operation	Status	Notes	AWS Docs
`ListImages`	⚠️ Partial	Returns image IDs (tag + digest); reconciles local registry tags into the store when Docker is available. Deliberately does not fail when the registry is transiently unreachable, unlike DescribeImages/BatchGetImage — it answers with whatever the store currently holds rather than ServerException, since an empty or stale list names no specific image to be wrong about	docs
`DescribeImages`	✅ Supported	Returns image detail objects (digest, tags, media type); an imageIds entry that resolves to nothing raises ImageNotFoundException; reconciles local registry manifests when Docker is available	docs
`PutImage`	✅ Supported	Stores an image manifest; generates a digest if none supplied	docs
`BatchGetImage`	✅ Supported	Fetches manifests by tag or digest; reconciles local registry manifests when Docker is available, and an unreachable registry answers ServerException rather than reporting an image falsely missing, mirroring DescribeImages	docs
`DescribeImageScanFindings`	🧊 Inert	Always reports imageScanStatus UNSUPPORTED_IMAGE with empty findings/enhancedFindings; no scan engine is emulated, regardless of scanOnPush or any registry/repository scanning configuration	docs
`BatchDeleteImage`	⚠️ Partial	Deletes images by tag or digest from the store; when Docker backs the repository, the registry itself is never asked to delete anything, so an image it still serves reappears on the next reconciling read (ListImages/DescribeImages/BatchGetImage) — unlike real ECR, where the deletion is durable	docs
`PutImageScanningConfiguration`	🧊 Inert	Stores scanOnPush and DescribeRepositories echoes it; no scan engine is emulated, so enabling it never makes DescribeImageScanFindings report anything but scanner-unavailable	docs
`StartImageScan`	❌ Unsupported	Not implemented, returns 501; no scan engine is emulated (see DescribeImageScanFindings)	docs
`GetRegistryScanningConfiguration`	❌ Unsupported	Not implemented, returns 501; registry-wide scanning configuration is not stored	docs
`PutRegistryScanningConfiguration`	❌ Unsupported	Not implemented, returns 501; registry-wide scanning configuration is not stored	docs

Policy

Operation	Status	Notes	AWS Docs
`SetRepositoryPolicy`	✅ Supported	Stores arbitrary IAM policy text	docs
`GetRepositoryPolicy`	✅ Supported	Retrieves stored policy; returns 400 if none set	docs
`DeleteRepositoryPolicy`	✅ Supported		docs
`PutLifecyclePolicy`	✅ Supported	Stores lifecycle policy text for the repository	docs
`GetLifecyclePolicy`	✅ Supported	Retrieves stored lifecycle policy; returns 400 if none set	docs
`DeleteLifecyclePolicy`	✅ Supported		docs

Tags

Operation	Status	Notes	AWS Docs
`TagResource`	✅ Supported	Adds/merges tags onto a repository ARN	docs
`UntagResource`	✅ Supported	Removes tag keys from a repository ARN	docs
`ListTagsForResource`	✅ Supported		docs

ECR — quick start, what works, and the differences from AWS
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