alexei.dolgolyov
389ed5aff8
Phase 3: Docker Engine API wrapper — pull/inspect images, container lifecycle (create/start/stop/remove/restart), network management, label-based container tracking, deterministic naming. Phase 4: Nginx Proxy Manager API client — JWT auth with auto-refresh, CRUD for proxy hosts, domain-based host lookup.
99 lines
5.2 KiB
Markdown
99 lines
5.2 KiB
Markdown
# Phase 3: Docker Client
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**Status:** :white_check_mark: Complete
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**Parent plan:** [PLAN.md](./PLAN.md)
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**Domain:** backend
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## Objective
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Implement the Docker Engine API wrapper for container lifecycle management — pull images, inspect, create/start/stop/remove containers, and manage networks.
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## Tasks
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- [x] Task 1: Create Docker client wrapper with socket connection (`/var/run/docker.sock`)
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- [x] Task 2: Implement `PullImage(ctx, image, tag, authConfig)` — pull with optional registry auth
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- [x] Task 3: Implement `InspectImage(ctx, image)` — extract EXPOSE ports, HEALTHCHECK, labels
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- [x] Task 4: Implement `CreateContainer(ctx, config)` — create with name, image, env, ports, network, labels
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- [x] Task 5: Implement `StartContainer(ctx, containerID)`, `StopContainer(ctx, containerID, timeout)`, `RemoveContainer(ctx, containerID, force)`
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- [x] Task 6: Implement `RestartContainer(ctx, containerID, timeout)`
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- [x] Task 7: Implement `ListContainers(ctx, filters)` — filter by labels to find managed containers
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- [x] Task 8: Implement `EnsureNetwork(ctx, networkName)` — create network if not exists
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- [x] Task 9: Implement `ConnectNetwork(ctx, networkID, containerID)` — attach container to network
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- [x] Task 10: Add docker-watcher labels to all managed containers (`docker-watcher.project`, `docker-watcher.stage`, `docker-watcher.instance-id`)
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## Files to Modify/Create
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- `internal/docker/client.go` — Docker client wrapper, connection setup
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- `internal/docker/container.go` — container lifecycle operations
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- `internal/docker/image.go` — pull and inspect operations
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- `internal/docker/network.go` — network management
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## Acceptance Criteria
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- Client connects to Docker socket
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- Pull handles both public and authenticated registries
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- Image inspection extracts port, healthcheck, and label metadata
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- Container creation applies all config (env, ports, network, labels)
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- All operations return meaningful errors
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- Managed containers are identifiable via labels
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## Notes
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- Use `github.com/docker/docker/client` SDK
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- Container names should be deterministic: `dw-{project}-{stage}-{tag-sanitized}`
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- All containers should be on the shared network (e.g., `staging-net`)
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- Port mapping: container's EXPOSE port → random host port (Docker auto-assigns)
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- Auth config for private registries will come from the store (encrypted tokens)
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## Review Checklist
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- [x] All tasks completed
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- [x] Proper context propagation for cancellation
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- [x] Resource cleanup (close client, remove failed containers)
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- [x] No hardcoded values
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- [x] Error messages include container/image identifiers
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## Handoff to Next Phase
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### Exported API surface (`internal/docker` package)
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**Client lifecycle:**
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- `docker.New() (*Client, error)` — creates client with env-based config and API version negotiation
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- `(*Client).Close() error` — releases resources
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- `(*Client).Ping(ctx) error` — checks daemon connectivity
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**Image operations (`image.go`):**
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- `(*Client).PullImage(ctx, imageRef, tag, authConfig) error` — pulls image; authConfig is base64-encoded JSON (use `EncodeRegistryAuth` helper)
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- `(*Client).InspectImage(ctx, imageRef) (ImageInfo, error)` — returns `ImageInfo{ExposedPorts, Healthcheck, Labels}`
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- `docker.EncodeRegistryAuth(username, password, serverAddress) (string, error)` — builds auth payload for `PullImage`
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**Container operations (`container.go`):**
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- `(*Client).CreateContainer(ctx, ContainerConfig) (containerID string, error)` — creates container with labels, env, ports, network
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- `(*Client).StartContainer(ctx, containerID) error`
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- `(*Client).StopContainer(ctx, containerID, timeoutSeconds) error`
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- `(*Client).RemoveContainer(ctx, containerID, force) error`
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- `(*Client).RestartContainer(ctx, containerID, timeoutSeconds) error`
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- `(*Client).ListContainers(ctx, labelFilters) ([]ManagedContainer, error)` — always scoped to docker-watcher labels
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- `(*Client).InspectContainerPort(ctx, containerID, containerPort) (uint16, error)` — gets auto-assigned host port
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- `docker.ContainerName(project, stage, tag) string` — deterministic name: `dw-{project}-{stage}-{tag-sanitized}`
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**Network operations (`network.go`):**
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- `(*Client).EnsureNetwork(ctx, networkName) (networkID string, error)` — idempotent create-if-not-exists
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- `(*Client).ConnectNetwork(ctx, networkID, containerID) error`
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**Label constants:**
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- `docker.LabelProject` = `"docker-watcher.project"`
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- `docker.LabelStage` = `"docker-watcher.stage"`
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- `docker.LabelInstanceID` = `"docker-watcher.instance-id"`
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**Key types:**
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- `docker.ContainerConfig` — input for `CreateContainer` (Name, Image, Env, ExposedPorts, NetworkName, NetworkID, Labels, Project, Stage, InstanceID)
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- `docker.ImageInfo` — output of `InspectImage` (ExposedPorts, Healthcheck, Labels)
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- `docker.ManagedContainer` — output of `ListContainers` (ID, Name, Image, Status, State, Project, Stage, InstanceID, Ports)
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### Dependencies added
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- `github.com/docker/docker v27.5.1+incompatible`
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- `github.com/docker/go-connections v0.5.0`
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- Run `go mod tidy` to resolve transitive dependencies before building
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### Conventions maintained
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- `context.Context` as first parameter on all methods
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- Errors wrapped with `fmt.Errorf("context: %w", err)`
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- Package-level constants for labels
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- Immutable patterns (new maps created rather than mutating input)
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