Files
cairnobs/docs/architecture.md
T
jcoffey-dev 1de77b969f Build per-tenant ClickHouse write-routing for ingest (Tantivy still deferred)
ingest tags every record with a tenant_id Kafka header (built previously),
but nothing consumed it to actually route the write. This closes that for
ClickHouse: enterprise/cmd/enterprise-ingest (a second binary, mirroring
enterprise-api) reuses ingest/consumer's own flush loop unchanged, with
enterprise/internal/chwriter.Registry -- a per-tenant clickhousewriter.Writer
registry -- swapped in as the writer. A batch pulled from the single shared
Redpanda topic can mix records from many tenants, so WriteBatch groups by
TenantID and dispatches each group to its own tenant's connection, fail-
closed on an empty or unrecognized tenant_id.

ingest/consumer and ingest/clickhousewriter move out of internal/ (same
reason api/internal/* moved earlier this phase: enterprise/ can't import
anything under another module's internal/). Their New() constructors now
take small local Config structs instead of ingest/internal/config types,
so enterprise/ doesn't need that import either.

Building this surfaced a real bug: tenantprovision.ProvisionClickHouse
only granted SELECT on a tenant's ClickHouse user, correct for chrunner's
read-only use but not enough for chwriter reusing the same credential to
write -- every real per-tenant write would have failed closed with a
permission error. Fixed by widening the grant to SELECT, INSERT; no
cross-tenant boundary is crossed by also allowing INSERT within a
tenant's own database.

Helm gates enterprise-ingest's Deployment on the same
ingest.requireTenantCredential flag that already gates tag validation --
write-routing is meaningless without tagging already being required, so
they're one decision, not two. docker-compose.yml's version is a
disclosed, weaker approximation: it can't achieve Helm's genuine
-mode=server/-mode=consumer split, so with the enterprise profile active
both ingest and enterprise-ingest independently consume every message
via different consumer groups -- harmless duplication for local
verification only.

Not built: Tantivy's independent Redpanda consumer (search/src/consumer.rs)
still doesn't read the tenant_id header at all -- every record still lands
in the one shared index regardless of tenant. Not run: the live-ClickHouse-
gated tests (chwriter's cross-tenant routing test, tenantprovision's INSERT
regression test) -- no Docker/database access in this environment; they're
correct Go that has never executed, disclosed as such in docs/security/
threat-model.md and docs/phase-4-runbook.md §14.
2026-08-14 19:26:09 -07:00

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Markdown

# Sentry Architecture
> **Status:** Updated through Phase 4. The component map/diagram below is
> still the Phase 0 request path (agent → ingest → ClickHouse → api →
> web) — it was never redrawn for the full-text search, dashboards/
> alerting, or enterprise/ additions; see each phase's runbook
> (`/docs/phase-N-runbook.md`) for what was actually verified when it
> shipped. The component responsibilities table and the sections below
> the diagram are kept current. Phase 0's original framing ("draft,
> correct as needed") still applies to anything not yet built.
## Mission
Open-core, Kubernetes-native centralized logging platform. Compete with
Splunk on features; win on cost-per-GB, a modern language stack, and
multi-tenant RBAC that's actually honest about its guarantees.
## Component map
```
┌──────────┐ gRPC/mTLS ┌──────────┐ produce ┌───────────┐ consume ┌────────────┐
│ agent │ ────────────▶ │ ingest │ ──────────▶ │ Redpanda │ ────────▶ │ ingest │
│ (Rust) │ │ (Go) │ │ (Kafka API)│ │ consumer │
└──────────┘ └──────────┘ └───────────┘ │ (Go) │
└──────┬─────┘
│ batch INSERT
┌────────────┐
│ ClickHouse │
└─────┬──────┘
│ SQL
┌───────────▼───────────┐
│ api (Go: gRPC+REST) │
└───────────┬───────────┘
│ REST
┌───────────▼───────────┐
│ web (SvelteKit) │
└────────────────────────┘
```
Decision (confirmed 2026-08-12): Redpanda stays in the Phase 0 path. The
`ingest` service's gRPC front end produces to Redpanda rather than writing
ClickHouse directly; a separate consumer path reads from Redpanda and batches
inserts into ClickHouse. This exercises the real transport layer from day
one instead of deferring it, and keeps Kafka credentials off the edge agent.
## Storage / query split
- **ClickHouse** is the analytical store of record for structured log data:
timestamp, host, service, severity, message, plus a `Map(String,String)`
for arbitrary structured fields. Partitioned by day, ordered by
`(service, timestamp)`.
- **Tantivy** (Phase 1) will provide full-text indexing over the `message`
field and unstructured payloads, queried out-of-band from ClickHouse and
joined by a log identifier. Not built in Phase 0.
- **Schema-on-write** using OTel semantic conventions as the default log
schema; schema-on-read fallback for unstructured/raw text that doesn't fit
the structured columns (captured via the `Map` column and/or a raw
passthrough field).
- **Postgres** (Phase 3) holds control-plane config only — dashboards,
panels, notification targets, alert rules/state, delivery log, and
(Phase 4) tenants/users/tenant_memberships/audit_log. Never log data;
ClickHouse/Tantivy stay the only place a log record itself lives. See
`/docs/phase-3-dashboard-design.md` for why ClickHouse's MergeTree
family isn't a fit for this (no real row-level locking/transactional
read-modify-write).
This split is not to be changed without discussion — see CLAUDE.md.
## Component responsibilities
| Component | Responsibility |
|---|---|
| `agent` (Rust, musl) | Tail a log file or read journald; parse RFC 5424 syslog with raw passthrough fallback; batch; ship via gRPC/mTLS to `ingest`. Windows (ETW/Event Log) code exists but is unverified on real Windows hardware — see `/agent/README.md`. |
| `proto` | Shared `.proto` contracts for agent↔ingest and api↔search gRPC, versioned independently of either side. |
| `transport` | Redpanda docker-compose + topic provisioning scripts. No application code. |
| `ingest` (Go) | gRPC server accepting agent connections; produces normalized OTel-log-like records to Redpanda; separate consumer reads from Redpanda and batch-writes to ClickHouse. No tenant concept — every record lands in the one shared `logs` table regardless of source (see "Tenant isolation" below). |
| `storage` | ClickHouse schema migrations + docker-compose for local/homelab. |
| `search` (Rust, Phase 1) | Consumes the same Redpanda topic `ingest` does (own offset tracking), builds a Tantivy full-text index over `message`, serves matches over gRPC. Writes always go to one shared (default) index (`ingest` isn't tenant-aware); reads can be scoped per-tenant via `SearchRequest.tenant_id` and `src/registry.rs`'s `IndexRegistry` (Phase 4) — see "Tenant isolation" below. |
| `api` (Go) | gRPC + REST gateway. `POST /query` compiles pipe-syntax or raw SQL to one IR, executed across ClickHouse/Tantivy (`/docs/query-language-design.md`). `internal/dashboards` is CRUD only — panel query execution happens client-side, reusing `/query`. `internal/authz` (Phase 4) enforces RBAC via a network call to `enterprise-auth`, never an import. |
| `alerting` (Go, Phase 3) | Evaluates alert rules on an interval, calls `api`'s `POST /query` (via a `RoleService` credential once Phase 4 auth is configured — see `/docs/phase-4-isolation-design.md`'s alerting↔api gap), delivers firing/resolved notifications (webhook/Slack/PagerDuty). |
| `enterprise` (Go, commercial license, Phase 4) | OIDC login (`internal/loginhandler`'s `/auth/oidc/login`+`/auth/oidc/callback`) and SAML login (`/auth/saml/login`+`/auth/saml/acs`, via `internal/saml`'s `crewjam/saml` wiring) — both a real IdP round trip, each verified with a real fake IdP (`coreos/go-oidc`'s `oidctest`, `crewjam/saml`'s `samlidp`) but not a real external one, RBAC storage (`internal/rbacstore`), session/service-token issuance (`internal/session`), the append-only audit log (`internal/audit`), `enterprise-auth`'s HTTP surface (`/internal/authorize`, `/auth/features`), per-tenant ClickHouse provisioning (`internal/tenantprovision`) and query routing (`internal/chrunner`), and `cmd/enterprise-api` — a second binary combining core's `api/queryapi`/`api/dashboards` handlers with these tenant-aware implementations. Never imported by core — see "Licensing boundary" below. Also `internal/searchclient` (per-tenant Tantivy routing, wired the same way into `search`). |
| `web` (SvelteKit, static build) | Query bar, dashboards, alerts, and (Phase 4) a settings page that renders SSO status via a runtime capability check (`GET /auth/features`) rather than bundling enterprise-licensed components. |
| `cli` (`sentryctl`) | `ping`, `query`, `dashboards` (list/get/apply), `alerts` (list/get/apply). `$SENTRYCTL_TOKEN`, if set, is forwarded as a Bearer credential (Phase 4). |
| `deploy` | A Helm chart covering every `docker-compose.yml` service, plus (Phase 4) a small Go Operator managing one CRD (`Tenant`) that provisions a per-tenant ClickHouse credential Secret. Never applied to a live cluster in the environment this was built in — see `/deploy/README.md`'s verification section before trusting it. |
## Tenant isolation model (Phase 4)
Full design rationale: `/docs/phase-4-isolation-design.md`. Full honest
accounting of what's actually enforced vs. designed-only:
`/docs/security/threat-model.md` — read that before assuming any claim
below holds for log data specifically.
**As designed:** one dedicated ClickHouse database + narrowly-granted
user per tenant (never the shared `default`/admin credential), one
dedicated Tantivy index directory per tenant, `system.*` access revoked
per tenant, connections resolved from an immutable per-tenant map (never
a shared pool with session-level `USE`). Isolation lives at the
**connection layer** — every query, compiled or raw SQL, is forced
through a tenant-scoped connection the database's own access control
enforces — not at the query-compiler layer, since Phase 2's raw-SQL
escape hatch is opaque to any compiler-injected filter.
**As built, currently:**
- Role-based access control (`api/authz`) is live on `/query`
and `/dashboards`, resolved via `enterprise-auth` over HTTP.
- Control-plane tenant scoping is live for dashboards
(`api/dashboards`'s store filters every query by the
authenticated identity's tenant, never a client-supplied field).
- The `alerting``api` service-identity gap (task 2's finding) is
closed: a `RoleService` credential, distinct from every human role.
- **ClickHouse connection-layer isolation is built**, but lives in a
second binary: `enterprise/internal/tenantprovision` (real `CREATE
DATABASE`/`CREATE USER`/`GRANT` against ClickHouse) and
`enterprise/internal/chrunner` (a per-tenant connection registry
implementing `api/querylang/executor.SQLRunner`, resolving the
right tenant's connection from the authenticated identity in request
context) are wired into `enterprise/cmd/enterprise-api` — a binary
that imports both `api`'s handler packages and enterprise's
tenant-aware implementations (the allowed `enterprise → api` import
direction; core still never imports `enterprise/`). Real integration
tests assert a tenant cannot read another tenant's database by
fully-qualified name, and that `system.query_log`/`system.tables`/
`SHOW DATABASES` don't leak across tenants either — written but not
yet run against a live ClickHouse in this environment, see
`/docs/security/threat-model.md` and `/docs/phase-4-runbook.md`'s
verification-status sections. Plain `api/cmd/api` still exists,
unchanged, with its single shared connection — nothing forces a
deployment to run `enterprise-api` instead, and nothing flags it if it
doesn't.
- **Tantivy index-layer isolation is built, and verified.**
`search/src/registry.rs`'s `IndexRegistry` resolves
`SearchRequest.tenant_id` (added to `proto/sentry/search/v1/
search.proto`) to its own on-disk index, opened on demand;
`enterprise/internal/searchclient` sets that field from the
authenticated request identity, the same "read from ctx, fail closed"
shape `chrunner` uses. Unlike the ClickHouse pieces, this one actually
ran in the environment it was built in — Tantivy is an embedded
library, so the cross-tenant isolation probe needed no live database
or Docker to execute for real, and it passed.
- **Ingest identity and ClickHouse write-routing are now built; Tantivy's
isn't.** `ingest` (AGPL core) gained an optional `TenantResolver`
(`ingest/internal/grpcserver`): an agent presents a per-tenant bearer
credential (`enterprise-auth -create-ingest-credential-tenant=<id>`
mints one, only its hash stored), validated over the network via a new
`POST /internal/authorize-ingest` endpoint (never an `enterprise/`
import — same "network boundary, not import boundary" shape
`api/authz.Authorizer` already uses), and the resolved tenant ID rides
as a `tenant_id` Kafka message header on every record produced.
`enterprise/cmd/enterprise-ingest` (another "second binary," mirroring
`enterprise-api`) consumes that tag: it reuses `ingest/consumer`'s own
flush loop with `enterprise/internal/chwriter.Registry` swapped in as
the writer, routing each batch's records to a per-tenant ClickHouse
connection (one per tenant, built from `rbacstore.
ListProvisionedDataSources` — the same source `chrunner` already uses
for reads), fail-closed on an untagged or unprovisioned tenant.
Building it found and fixed a real bug: `tenantprovision.
ProvisionClickHouse` originally granted a tenant's ClickHouse user
`SELECT` only, which would have made every real per-tenant write fail
with a permission error — fixed by granting `SELECT, INSERT` (one
credential, both directions; no cross-tenant boundary is crossed by
also allowing INSERT within a tenant's own database). What isn't built
yet: `search`'s independent Redpanda consumer (a different codebase —
Rust — and a different process, not reachable through either `ingest`
or `enterprise-ingest`) still writes every record into the one shared
Tantivy index regardless of tenant. That's real, disclosed, separately
scoped remaining work, not something this change claims to have
closed.
- `deploy/operator`'s `Tenant` CRD and `enterprise-api -provision-tenant`
are now unified, deliberately lightweight: `-provision-tenant` stays
the sole real actor (ClickHouse + `rbacstore`), and now also syncs its
real result into the `Tenant` CRD (`enterprise/internal/tenantcrd`) --
a real credential Secret, and status fields the reconciler
(`deploy/operator/internal/controller`) derives `Phase`/`Ready` from
rather than independently guessing. The reconciler itself gained no
new credentials and still never touches ClickHouse/Postgres.
**The deployment-topology gap is closed for both Helm and
docker-compose**: `deploy/helm/sentry/templates/api.yaml`/
`enterprise-api.yaml` are mutually exclusive on `enterprise.enabled`,
rendering to the same Service name and port either way, so a
Helm-deployed cluster can't accidentally run the wrong binary — the same
flag that turns on RBAC/audit/SSO now also chooses the query binary.
`docker-compose.yml`'s `api`/`enterprise-api` services are the same
mutually-exclusive choice via `COMPOSE_PROFILES` (`.env` defaults to
plain `api`), sharing a host-port/network-alias trick so `alerting`/
`web` need no conditional config either way. With both storage engines'
connection/index-layer mechanisms built, deployment topology enforced at
both the Helm and docker-compose layers, and the two provisioning
mechanisms unified, the largest remaining gap is ingest's per-tenant
*write-routing* (identity is now attached at ingest time; nothing
downstream of Redpanda consumes it yet to isolate the write, see above).
## Licensing boundary
AGPLv3 for core + agents. Enterprise features (SSO, RBAC storage, audit
logging) live under `enterprise/` (commercial license stub, added
Phase 4). AGPL code must never import from `enterprise/` — enforced in
CI by `hack/check-tenant-boundary.sh`, which greps every build for the
import edge. Where core needs a decision only `enterprise/` can make
(is this request authorized, what SSO is configured), it calls
`enterprise-auth` over plain HTTP instead
(`api/authz.HTTPAuthorizer`, `web`'s `GET /auth/features`) —
the same "network boundary, not import boundary" shape `/alerting``api`
already used before `enterprise/` existed.
## Non-negotiables carried from CLAUDE.md
- Rust agent: statically linked musl, `x86_64-unknown-linux-musl` and
`aarch64-unknown-linux-musl`, no glibc runtime deps.
- Windows support via native ETW/Event Log API, not WSL — designed
(Phase 1) but still unverified on real Windows hardware.
- Every UI action maps to a documented REST/gRPC call — no UI-only logic.
- Pinned stack (see CLAUDE.md table) — no substitutions without discussion.
## Explicitly out of scope (current, Phase 4)
Per `/CLAUDE.md`'s Phase 4 non-goals and `/docs/security/threat-model.md`:
deny-override permission grants, a data retention/deletion policy for
deprovisioned tenants, general multi-cluster orchestration in `/deploy`,
and any defense against a privileged ClickHouse/Postgres administrator —
every isolation and audit-integrity guarantee here is a structural
defense against application-layer bugs, not an operational control.
## Open questions for you to resolve
- Retention/TTL policy for the ClickHouse `logs` table — not specified yet,
deferred until storage sizing is a real concern.
- Exact OTel log schema field mapping (which OTel resource/log attributes
map to which ClickHouse columns) — Phase 0 uses a minimal subset
(timestamp, host, service, severity, message, attributes map); full
mapping deferred.
- mTLS certificate provisioning/rotation story for agents — Phase 0 will use
a static dev CA and manually issued certs; production PKI design is
out of scope here.