fix(node): bound REST blob reads

.env.example

@@ -125,6 +125,8 @@ GITLAWB_MAX_PACK_BYTES=2147483648
 # rather than giving each stage a full budget: a walk that consumes it leaves the
 # serve nothing and the clone gets a 504. Serving large path-scoped repos may
 # need a higher value here than when each stage was budgeted separately.
+# REST blob size probes and content reads also share this deadline and return 504 on timeout.
+# Body delivery gets the same time allowance; expiry aborts the response and releases admission.
 # Must be 1..=3153600000 (100 years): the node derives deadlines from this value,
 # and a larger one cannot be represented. Default 600.
 GITLAWB_GIT_SERVICE_TIMEOUT_SECS=600
@@ -139,8 +141,10 @@ GITLAWB_GIT_SERVICE_TIMEOUT_SECS=600
 # cost centers. Must be positive; set very large to effectively disable. Default 30.
 GITLAWB_GIT_ACQUIRE_TIMEOUT_SECS=30
 
-# Max concurrent git READ ops (upload-pack + the upload-pack info/refs
-# advertisement) served at once, a global pool separate from the push pool below.
+# Max concurrent git READ ops (upload-pack, its info/refs advertisement, and REST
+# blob reads) served at once, a global pool separate from the push pool below.
+# REST blobs also have a fixed four-response sub-pool and a 32 MiB per-response
+# ceiling; their permits remain held until the response body finishes or disconnects.
 # The anon receive-pack info/refs advertisement has its OWN pool (see below), not
 # this one. Over-cap sheds a clean 503 + Retry-After. Anonymous reads draw from
 # here, so pair it with GITLAWB_MAX_CONCURRENT_READS_PER_CALLER (below) so one
@@ -182,6 +186,7 @@ GITLAWB_MAX_CONCURRENT_PIN_TASKS=8
 # collapses to one global cap. Set GITLAWB_TRUSTED_PROXY for per-client keying; a
 # high-fanout caller (CI behind one NAT) then needs the operator to raise this.
 # Default 16.
+# REST blob downloads also acquire this per-caller read allowance.
 GITLAWB_MAX_CONCURRENT_READS_PER_CALLER=16
 
 # Two further per-source concurrency caps exist on the PUSH side but have NO

README.md

@@ -144,6 +144,10 @@ Or build from source:
 cargo build --release -p gl -p git-remote-gitlawb -p gitlawb-node
 ```
 
+Node promisor mirrors use a 10 GiB blob filter on Unix. Git for Windows requires
+a filter below 4 GiB, so Windows mirrors use 4 GiB minus one byte; larger blobs
+remain available through on-demand fetching.
+
 Put these binaries on your `PATH`:
 
 ```txt
@@ -340,6 +344,11 @@ GET /{owner}/{repo}/info/refs
 POST /{owner}/{repo}/git-upload-pack
 ```
 
+REST blob reads serve file content only; directory and gitlink paths return 404.
+Body delivery has its own allowance equal to `GITLAWB_GIT_SERVICE_TIMEOUT_SECS`.
+If delivery exceeds it, the response is interrupted and its admission slots are released.
+Blob responses use `Cache-Control: no-store` because they may contain private content.
+
 Signed write routes include:
 
 ```txt
@@ -396,9 +405,9 @@ Important node settings:
 | `GITLAWB_ENFORCE_OWNER_PUSH` | Require the authenticated pusher to be the repo owner on `git-receive-pack`. **Defaults to `true`.** A `did:key` signature is authentication, not authorization — anyone can mint a key and sign — so with this off every signed caller may push to every repository, private ones included. Delegated and CI keys count as non-owners: a UCAN `git/push` capability is verified but not yet honored for authorization, so they cannot push while this is on. Set `false` only for a rolling upgrade; see [`docs/RUN-A-NODE.md`](docs/RUN-A-NODE.md). |
 | `GITLAWB_AUTO_SYNC` | Enable automatic sync from known peers. |
 | `GITLAWB_MAX_PACK_BYTES` | Max git pack body size for smart-HTTP routes. |
-| `GITLAWB_GIT_SERVICE_TIMEOUT_SECS` | Max seconds a served git upload-pack, receive-pack, or `info/refs` advertisement may run before it is aborted (504). Default 600. Also bounds the withheld-blob classification walk (on both the upload-pack serve and receive-pack replication paths) and the push-side pin-candidate discovery (`rev-list` / `cat-file`), each reaped via process-group teardown at the deadline. On the path-scoped upload-pack path the classification walk and the pack serve share ONE deadline, so this value bounds their combined duration rather than granting each stage a full budget: a walk that consumes it leaves the serve nothing and the clone gets a 504. Serving large path-scoped repos may therefore need a higher value than they did when each stage was budgeted separately. Accepted range is 1 to 3153600000 (100 years), since the node derives deadlines from this value and a larger one cannot be represented. |
+| `GITLAWB_GIT_SERVICE_TIMEOUT_SECS` | Max seconds a served git upload-pack, receive-pack, `info/refs` advertisement, or REST blob read may run before it is aborted (504). Default 600. Also bounds the withheld-blob classification walk (on both the upload-pack serve and receive-pack replication paths) and the push-side pin-candidate discovery (`rev-list` / `cat-file`), each reaped via process-group teardown at the deadline. On the path-scoped upload-pack path the classification walk and the pack serve share ONE deadline, so this value bounds their combined duration rather than granting each stage a full budget: a walk that consumes it leaves the serve nothing and the clone gets a 504. Serving large path-scoped repos may therefore need a higher value than they did when each stage was budgeted separately. Accepted range is 1 to 3153600000 (100 years), since the node derives deadlines from this value and a larger one cannot be represented. |
 | `GITLAWB_GIT_ACQUIRE_TIMEOUT_SECS` | Max seconds the storage-acquisition phase (Tigris HEAD/GET, push advisory-lock) of a served git op may run before the request is shed with a 503, separate from the git-run timeout. The concurrency permit is released on expiry so a stalled backend cannot pin the pool. Default 30. |
-| `GITLAWB_MAX_CONCURRENT_GIT_OPS` | Max concurrent served git READ ops (upload-pack and its `info/refs` advertisement) across all callers; over-cap sheds a 503 + Retry-After. Anonymous reads draw from this pool, so pair it with `GITLAWB_MAX_CONCURRENT_READS_PER_CALLER`. Pushes and the receive-pack advertisement have their own pools, so a read flood cannot shed an authenticated push. Default 128. |
+| `GITLAWB_MAX_CONCURRENT_GIT_OPS` | Max concurrent served git READ ops (upload-pack, its `info/refs` advertisement, and REST blob reads) across all callers; over-cap sheds a 503 + Retry-After. Anonymous reads draw from this pool, so pair it with `GITLAWB_MAX_CONCURRENT_READS_PER_CALLER`. Pushes and the receive-pack advertisement have their own pools, so a read flood cannot shed an authenticated push. Default 128. REST blob responses are limited to 32 MiB each and a dedicated four-request pool holds admission through body delivery, bounding retained blob data to 128 MiB. |
 | `GITLAWB_MAX_CONCURRENT_GIT_PUSHES` | Max concurrent `git-receive-pack` POST operations, in a pool separate from the read pool. The anon receive-pack `info/refs` advertisement runs in a third pool of the same size, disjoint from both, so an advertisement flood cannot shed a push either. Two per-source push caps are derived from this value (`/8`, floor 1) and have no env var of their own. Over-cap sheds a 503 + Retry-After. Default 32. |
 | `GITLAWB_MAX_CONCURRENT_READS_PER_CALLER` | Max concurrent read ops a single caller may hold, so one caller cannot monopolize the read pool. Keyed on the resolved source IP, never the DID, and only as granular as `GITLAWB_TRUSTED_PROXY`: left unset, a node behind an edge or NAT keys every caller on the edge IP and this collapses to one global cap. Default 16. |
 | `GITLAWB_MAX_CONCURRENT_PIN_TASKS` | Max post-push pin loops (IPFS + Pinata) running concurrently across all repos. This caps how many loops RUN at once, not how much object-id list memory the node retains: on the local IPFS path a loop parked waiting for a permit still holds its full list. Do not size memory from this knob alone. A loop over cap waits, never drops a pin. Default 8. |

crates/gitlawb-node/src/api/ipfs.rs

@@ -8338,6 +8338,7 @@ mod tests {
     #[tokio::test]
     async fn get_by_cid_per_source_cap_sheds_same_source_admits_other() {
         let mut state = crate::test_support::test_state_lazy();
+        state.db.pool().close().await;
         // Global pool has room; the per-source cap is 1.
         state.git_ipfs_walk_semaphore = Arc::new(Semaphore::new(8));
         state.git_ipfs_walk_per_caller = crate::rate_limit::PerCallerConcurrency::new(1, 100);
@@ -8364,16 +8365,23 @@ mod tests {
             "a source at its per-source /ipfs walk cap must shed 503 with global capacity free"
         );
 
+        let bytes = axum::body::to_bytes(resp.into_body(), 1024).await.unwrap();
+        let body: serde_json::Value = serde_json::from_slice(&bytes).unwrap();
+        assert_eq!(body["error"], "overloaded");
+
         // A DIFFERENT source is NOT shed by the per-source cap: it clears admission and
-        // proceeds (then errors on the lazy DB, which is not a 503).
+        // proceeds to the closed DB, which has a distinct db_unavailable error code.
         let resp = ipfs_router(state)
             .oneshot(get_cid(&cid, Some(other)))
             .await
             .unwrap();
-        assert_ne!(
-            resp.status(),
-            StatusCode::SERVICE_UNAVAILABLE,
-            "a different source must not be shed by the per-source cap"
+        assert_eq!(resp.status(), StatusCode::SERVICE_UNAVAILABLE);
+        let bytes = axum::body::to_bytes(resp.into_body(), 1024).await.unwrap();
+        let body: serde_json::Value = serde_json::from_slice(&bytes).unwrap();
+        assert_eq!(
+            body["error"],
+            crate::error::DB_UNAVAILABLE_CODE,
+            "a different source must clear admission and reach the closed database"
         );
     }