feat(CubeAPI): support e2b V3 template-build protocol end-to-end

CubeAPI/Cargo.toml

@@ -54,7 +54,7 @@ config = "0.13"
 dotenvy = "0.15"
 
 # ── UUID ──────────────────────────────────────────────────────────────────
-uuid = { version = "1", features = ["v4", "serde"] }
+uuid = { version = "1", features = ["v4", "v5", "serde"] }
 
 # ── High-concurrency in-memory state ──────────────────────────────────────
 # Lock-free concurrent HashMap: O(1) reads without global lock
@@ -69,7 +69,7 @@ governor = { version = "0.6", features = ["dashmap"] }
 
 # ── HTTP client (orchestrator / backend calls) ────────────────────────────
 # connection pool built-in, rustls for TLS
-reqwest = { version = "0.12", features = ["json", "rustls-tls"], default-features = false }
+reqwest = { version = "0.12", features = ["json", "rustls-tls", "stream"], default-features = false }
 
 # ── Validation ────────────────────────────────────────────────────────────
 validator = { version = "0.16", features = ["derive"] }

CubeAPI/src/config/mod.rs

@@ -64,6 +64,123 @@ pub struct ServerConfig {
     /// Example: mysql://cube:cube_pass@127.0.0.1:3306/cube_mvp
     #[serde(default = "default_database_url")]
     pub database_url: Option<String>,
+
+    /// E2B-compatible OCI registry upstream URL. When set, /v2/* requests are
+    /// reverse-proxied to this address so that `e2b template build` (which uses
+    /// `docker push`) can upload images that CubeMaster will later consume.
+    ///
+    /// Recommended deployment: run `distribution/distribution` (CNCF Registry)
+    /// as a sidecar listening on 127.0.0.1:5000 and set
+    /// CUBE_API_REGISTRY_UPSTREAM=http://127.0.0.1:5000.
+    ///
+    /// When unset, /v2/* returns 503 and `dockerfile`-based template requests
+    /// are rejected with 501.
+    ///
+    /// ## Security contract — read this before exposing CubeAPI publicly
+    ///
+    /// CubeAPI itself enforces **per-build, short-lived push credentials**
+    /// on every `/v2/*` path other than the unauthenticated `GET /v2/` ping
+    /// (which is required by the docker / oci-distribution handshake). The
+    /// credential is minted at build-creation time, returned to the SDK in
+    /// the `registry` field of the build response, indexed inside the
+    /// in-memory `BuildRegistry`, and is repo-scoped: it can only push /
+    /// pull blobs and manifests under `<repo_prefix>/<templateID>`. It is
+    /// dropped when the build reaches its terminal stage (TTL- or
+    /// size-cap-evicted by `BuildRegistry`).
+    ///
+    /// **Strongly recommended** in addition: run an authenticated upstream
+    /// (e.g. `distribution/distribution` with htpasswd) and bind CubeAPI
+    /// itself behind TLS + an HTTP authenticator. Both layers together
+    /// match the depth of access control most operators expect from a
+    /// public OCI registry.
+    ///
+    /// **Not safe**: setting `registry_upstream` to an unauthenticated
+    /// upstream *and* binding CubeAPI on a public interface without TLS.
+    /// CubeAPI's own credential gate covers the bulk of the attack
+    /// surface, but it cannot stop a network attacker from observing the
+    /// per-build password in transit. CubeAPI logs a `WARN` at startup
+    /// when this combination is detected (see
+    /// `AppState::log_registry_security_posture`).
+    #[serde(default)]
+    pub registry_upstream: Option<String>,
+
+    /// Public host (no scheme) advertised to E2B clients as the docker-push
+    /// target, e.g. "cube.example.com". Defaults to the Host header of the
+    /// originating /templates request when unset.
+    #[serde(default)]
+    pub registry_public_host: Option<String>,
+
+    /// Repository namespace prefix for uploaded build images. The full image
+    /// reference returned to CubeMaster will be:
+    ///   <registry_pull_host>/<repo_prefix>/<templateID>:<buildID>
+    /// Default: "e2b".
+    #[serde(default = "default_registry_repo_prefix")]
+    pub registry_repo_prefix: String,
+
+    /// Internal registry host CubeMaster nodes should pull from (e.g.
+    /// "10.0.0.1:5000"). Defaults to `registry_upstream` host:port when unset.
+    #[serde(default)]
+    pub registry_pull_host: Option<String>,
+
+    /// Optional shared secret printed back as `registry.password` in
+    /// POST /templates responses. Empty → "_anon".
+    #[serde(default)]
+    pub registry_token: Option<String>,
+
+    /// Default `writable_layer_size` to send to CubeMaster when the client
+    /// (e.g. the E2B Python SDK) does not specify one. CubeMaster validates
+    /// this field as required, so a non-empty default is needed for the V3
+    /// flow to work out of the box.
+    ///
+    /// Env var: CUBE_API_DEFAULT_WRITABLE_LAYER_SIZE  |  Default: "1G".
+    #[serde(default = "default_writable_layer_size")]
+    pub default_writable_layer_size: String,
+
+    /// How long (seconds) a *terminal* build (Ready / Error) is kept in the
+    /// in-memory `BuildRegistry` after reaching its terminal stage. Past this
+    /// TTL the build context (create request, credentials, logs, …) is
+    /// evicted by the background GC.
+    ///
+    /// 0 disables TTL-based eviction (only the size cap will fire).
+    /// Default: 3600 (1 hour) — comfortably covers slow log pollers without
+    /// retaining old builds for the lifetime of the process.
+    #[serde(default = "default_build_registry_terminal_ttl_secs")]
+    pub build_registry_terminal_ttl_secs: u64,
+
+    /// Hard upper bound on the number of *logical* builds tracked in the
+    /// `BuildRegistry`. When exceeded, the oldest terminal builds are
+    /// evicted FIFO regardless of TTL. In-flight builds are never evicted by
+    /// this cap (a warning is logged if the cap can't be honoured because
+    /// every entry is still in-flight).
+    ///
+    /// 0 disables the cap (only TTL applies). Default: 5000.
+    #[serde(default = "default_build_registry_max_entries")]
+    pub build_registry_max_entries: usize,
+
+    /// Interval (seconds) at which the background GC task scans the
+    /// `BuildRegistry` for TTL-expired terminal builds. Default: 300 (5 min).
+    /// 0 disables the background task entirely (size-cap eviction at
+    /// `create()` time still applies).
+    #[serde(default = "default_build_registry_gc_interval_secs")]
+    pub build_registry_gc_interval_secs: u64,
+}
+
+fn default_registry_repo_prefix() -> String {
+    "e2b".to_string()
+}
+
+fn default_build_registry_terminal_ttl_secs() -> u64 {
+    3600
+}
+fn default_build_registry_max_entries() -> usize {
+    5000
+}
+fn default_build_registry_gc_interval_secs() -> u64 {
+    300
+}
+
+fn default_writable_layer_size() -> String {
+    std::env::var("CUBE_API_DEFAULT_WRITABLE_LAYER_SIZE").unwrap_or_else(|_| "1G".to_string())
 }
 
 fn default_bind() -> String {
@@ -142,6 +259,15 @@ impl Default for ServerConfig {
             log_prefix: default_log_prefix(),
             auth_callback_url: None,
             database_url: default_database_url(),
+            registry_upstream: None,
+            registry_public_host: None,
+            registry_repo_prefix: default_registry_repo_prefix(),
+            registry_pull_host: None,
+            registry_token: None,
+            default_writable_layer_size: default_writable_layer_size(),
+            build_registry_terminal_ttl_secs: default_build_registry_terminal_ttl_secs(),
+            build_registry_max_entries: default_build_registry_max_entries(),
+            build_registry_gc_interval_secs: default_build_registry_gc_interval_secs(),
         }
     }
 }

CubeAPI/src/constants.rs

@@ -6,3 +6,7 @@
 
 /// Reported `envdVersion` for sandbox APIs (create, connect, list, get, resume, etc.).
 pub const ENVD_VERSION: &str = "0.2.0";
+
+/// E2B `envd` listens on this port inside every sandbox.
+pub const ENVD_PORT: u32 = 49983;
+pub const ENVD_PORT_STR: &str = "49983";

CubeAPI/src/handlers/mod.rs

@@ -6,7 +6,9 @@ pub mod agenthub;
 pub mod cluster;
 pub mod config;
 pub mod health;
+pub mod registry;
 pub mod sandboxes;
 pub mod snapshots;
 pub mod store;
 pub mod templates;
+pub mod templates_v3;