Add Render deployment (Docker cron job + one-off jobs)

.dockerignore

@@ -0,0 +1,6 @@
+bin/
+.git/
+.github/
+docs/
+example_configs/
+*.md

Dockerfile

@@ -0,0 +1,34 @@
+# Stage 1: build the Go binary
+FROM golang:1-alpine AS builder
+
+WORKDIR /build
+
+# Cache module downloads across builds
+COPY go.mod go.sum ./
+RUN go mod download
+
+# Build a static binary (no cgo) for the runtime image
+COPY . .
+RUN CGO_ENABLED=0 GOOS=linux go build -o oba-validator ./cmd/oba-validator
+
+# Stage 2: minimal runtime
+FROM alpine:3
+
+# HTTPS to the OBA API and the GTFS / GTFS-realtime feeds needs CA certificates.
+RUN apk add --no-cache ca-certificates
+
+WORKDIR /app
+COPY --from=builder /build/oba-validator /app/oba-validator
+COPY entrypoint.sh /app/entrypoint.sh
+RUN chmod +x /app/entrypoint.sh
+
+# entrypoint.sh base64-decodes its argument into the config JSON before invoking
+# the validator. This is required because a Render one-off job's startCommand is
+# split on whitespace and passed as argv (no shell), so the JSON — which has
+# spaces and special characters — must be base64-encoded by the caller:
+# `/app/entrypoint.sh <base64-config>`. (Render uses the startCommand's first
+# token as the executable, hence naming entrypoint.sh explicitly.) See "Deploying
+# to Render" in the README. No API key is baked in — keys are per-server and
+# travel in the config.
+ENTRYPOINT ["/app/entrypoint.sh"]
+CMD []

Makefile

@@ -1,8 +1,9 @@
 BINARY := oba-validator
 PKG    := ./cmd/oba-validator
 BIN    := bin/$(BINARY)
+IMAGE  := oba-validator
 
-.PHONY: all build test test-live vet fmt run clean tidy install
+.PHONY: all build test test-live vet fmt run clean tidy install docker-build
 
 all: build
 
@@ -38,6 +39,10 @@ tidy:
 install:
 	go install $(PKG)
 
+## docker-build: build the deployment image (see render.yaml)
+docker-build:
+	docker build -t $(IMAGE) .
+
 ## clean: remove build artifacts
 clean:
 	rm -rf bin

README.md

@@ -47,12 +47,63 @@ os.Exit(rep.ExitCode())
 
 ## Development
 
-    make build       # compile to bin/oba-validator
-    make test        # run unit tests (no network)
+    make build         # compile to bin/oba-validator
+    make test          # run unit tests (no network)
     make run ARGS=config.json
-    make test-live   # env-gated live test against the real server
+    make test-live     # env-gated live test against the real server
+    make docker-build  # build the deployment image
 
 Run `make` with no target to build. See the `Makefile` for all targets.
 
-See `docs/superpowers/specs/2026-05-24-oba-validator-design.md` for the full
-design.
+## Deploying to Render
+
+The validator deploys to [Render](https://render.com) as a Docker **cron job**
+whose schedule (`0 2 29 2 *`, Feb 29 02:00 UTC) makes it effectively never run on
+its own. Real validations are launched on demand as **one-off jobs** against the
+service, with the entire config — including `apiKey` — passed as the start
+command. Nothing server-specific is baked into the image, so one deployment can
+validate any OBA server.
+
+Build the image locally to verify it (the container accepts raw JSON directly):
+
+    make docker-build
+    docker run --rm oba-validator '{"obaServerURL":"https://api.pugetsound.onebusaway.org","apiKey":"org.onebusaway.iphone","dataSources":[{"agencyMapping":{"KCM":"1"},"staticGtfsFeedURL":"https://metro.kingcounty.gov/GTFS/google_transit.zip","vehiclePositionsURL":"https://s3.amazonaws.com/kcm-alerts-realtime-prod/vehiclepositions.pb"}]}'
+
+Deploy by pointing a Render Blueprint at `render.yaml`, or create the cron job by
+hand in the dashboard (Docker runtime, the schedule above, no environment
+variables needed).
+
+### Triggering a validation (one-off job)
+
+Render runs a one-off job's start command by **splitting it on whitespace and
+passing it as argv — there is no shell**, and the first token is used as the
+executable. A JSON config can't be passed inline (it has spaces and special
+characters), so **base64-encode the config** into a single token and let the
+image's `entrypoint.sh` decode it. The start command is:
+
+    /app/entrypoint.sh <base64-of-compact-config-json>
+
+Produce the token from your config (note the `apiKey` lives *in* the config — it
+is never baked into the image, since keys differ per server):
+
+    printf '%s' '{"obaServerURL":"https://api.example.org","apiKey":"your-key","dataSources":[{"agencyMapping":{"X":"1"},"staticGtfsFeedURL":"https://.../gtfs.zip","vehiclePositionsURL":"https://.../vp.pb"}]}' | base64 | tr -d '\n'
+
+Trigger it via the API (base64 is plain `[A-Za-z0-9+/=]`, so no escaping needed):
+
+    curl --request POST 'https://api.render.com/v1/services/<service-id>/jobs' \
+      --header 'Authorization: Bearer <render-api-key>' \
+      --header 'Content-Type: application/json' \
+      --data-raw '{"startCommand": "/app/entrypoint.sh <base64-config>"}'
+
+From Ruby (e.g. an obacloud job), this mirrors the existing pattern:
+
+    encoded = Base64.strict_encode64(config.to_json)
+    start_command = "/app/entrypoint.sh #{encoded}"
+
+Validator flags go after the token (`/app/entrypoint.sh <base64> --json`). The
+job's exit status is the validator's exit code (`0` no failures, `1` ≥1 failure,
+`2` config/usage error), so a failed validation shows as a failed run.
+
+See `docs/superpowers/specs/2026-05-24-oba-validator-design.md` for the validator
+design and `docs/superpowers/specs/2026-05-25-render-deployment-design.md` for the
+deployment design.

docs/superpowers/specs/2026-05-25-render-deployment-design.md

@@ -0,0 +1,158 @@
+# Render Deployment — Design
+
+**Date:** 2026-05-25
+**Status:** Approved (chat); invocation model corrected after PR review against
+obacloud's production Render integration.
+
+## Purpose
+
+Add the artifacts needed to deploy `oba-validator` to [Render](https://render.com)
+as a **Docker-runtime cron job** whose schedule is set so far in the future that
+it effectively never fires on its own. Real validations are launched on demand as
+**one-off jobs** against that service, with the entire config — including the
+per-server `apiKey` — passed (base64-encoded) in the job's start command.
+
+This mirrors the deployment approach of the sibling `gtfs-merge-service` repo
+(multi-stage Dockerfile) and obacloud's existing Render one-off-job pattern
+(`/app/entrypoint.sh <base64>`), adapted to this pure-Go tool.
+
+## Key constraint: keys are per-server
+
+OneBusAway `apiKey` values differ from one OBA server to the next. Therefore **no
+key is baked into the image, the Blueprint, or a service-level env var.** The
+whole config (with `apiKey`) is supplied — base64-encoded — at invocation time.
+The image and `render.yaml` are key-agnostic.
+
+## Invocation model
+
+Render cron jobs and one-off jobs both run the service's container. We exploit
+two facts:
+
+1. A cron job needs a schedule. We use `0 2 29 2 *` (Feb 29 02:00 UTC), so the
+   automatic run happens at most once every ~4 years — i.e. "virtually never."
+2. A **one-off job** runs against an existing service with a caller-supplied
+   `startCommand`, inheriting the latest build. This is how real validations are
+   triggered.
+
+**How Render runs the start command (verified against obacloud's production
+integration, `app/jobs/api_key_service_job.rb` and `apply_merge_transform_rule_set_job.rb`):**
+Render **splits the start command on whitespace and passes it as argv — there is
+no shell** (quotes are not stripped), and the **first token is the executable**.
+The image `ENTRYPOINT` is therefore *overridden* by a one-off job's start command,
+not appended to. So the start command must name an executable first, and any
+argument with spaces or shell-special characters must be encoded into a single
+token.
+
+The validator's config is JSON — full of spaces and special characters — so it
+cannot be passed inline. We mirror obacloud's established pattern: **base64-encode
+the config** and ship a small `entrypoint.sh` that decodes it. The one-off start
+command is:
+
+```
+/app/entrypoint.sh <base64-of-compact-config-json>
+```
+
+`entrypoint.sh` base64-decodes its argument and execs `oba-validator` with the
+resulting JSON as the sole positional argument (`config.Load` accepts a raw JSON
+string). As a convenience, an argument that already starts with `{` is treated as
+raw JSON and passed through unchanged — base64 never starts with `{`, so the two
+cases are unambiguous and local `docker run` stays ergonomic. The `apiKey` rides
+inside the encoded config; nothing key-related is in the image.
+
+## Artifacts
+
+All new, except edits to `README.md` and `Makefile`.
+
+### `Dockerfile` (multi-stage, pure Go)
+
+- **Builder:** `golang:1-alpine`. Copy `go.mod`/`go.sum`, `go mod download`, copy
+  source, then `CGO_ENABLED=0 GOOS=linux go build -o oba-validator ./cmd/oba-validator`.
+- **Runtime:** `alpine:3` + `ca-certificates` (required for HTTPS to the OBA API
+  and the GTFS / GTFS-realtime feed URLs). Alpine over distroless so `/bin/sh` and
+  busybox `base64` are available for the entrypoint and for debugging one-off runs.
+- Copies in `entrypoint.sh` and sets `ENTRYPOINT ["/app/entrypoint.sh"]`,
+  `CMD []`. The `ENTRYPOINT` governs scheduled and local runs; a one-off job
+  overrides it but names `entrypoint.sh` as its first token by convention.
+
+### `entrypoint.sh`
+
+A POSIX `sh` script that base64-decodes its first argument into the config JSON
+and `exec`s `/app/oba-validator` with it (forwarding any trailing flags before the
+config). An argument starting with `{` is passed through as raw JSON. `set -eu`
+makes a bad/empty argument fail loudly (no silent fallthrough). Required because
+Render passes the start command as whitespace-split argv with no shell.
+
+### `render.yaml` (Blueprint)
+
+```yaml
+services:
+  - type: cron
+    name: oba-validator
+    runtime: docker
+    dockerfilePath: ./Dockerfile
+    schedule: "0 2 29 2 *"   # Feb 29 02:00 UTC — effectively never
+    plan: starter            # cron jobs are not free-tier; adjust as needed
+```
+
+No `envVars` (per the per-server-key constraint). No `dockerCommand`: the rare
+scheduled fire runs `entrypoint.sh` with no args, which prints usage and exits 2 —
+harmless, at most once every ~4 years.
+
+### `.dockerignore`
+
+Exclude build/dev artifacts that don't belong in the build context:
+`bin/`, `.git/`, `docs/`, `.github/`, `*.md`, `example_configs/`. (Configs are
+not baked in; the base64-encoded config is the input path.)
+
+### `Makefile`
+
+Add a `docker-build` target: `docker build -t oba-validator .`.
+
+### `README.md`
+
+Add a **Deploying to Render** section covering: local image build, deploying via
+the Blueprint, base64-encoding the config, the `POST /v1/services/<id>/jobs` curl
+with `"startCommand": "/app/entrypoint.sh <base64>"`, the equivalent Ruby
+(`Base64.strict_encode64`) for obacloud, and the exit-code meaning.
+
+### Dropped from the merge-service pattern
+
+- **`env.example`** — not created. There is no env var to set (the key lives in
+  the config JSON).
+
+## Filesystem / cache
+
+The static-GTFS cache defaults to `os.UserCacheDir()/oba-validator`, falling back
+to `os.TempDir()` (`/tmp`) when `$HOME` is unset; `MkdirAll` creates it. In the
+container this just works and is ephemeral per run. **No persistent disk is
+required** — a fresh cache each run is correct for an on-demand validator.
+
+## Exit codes (already implemented; documented here)
+
+`0` = no failures · `1` = ≥1 failure · `2` = config/usage error. These surface as
+the Render job's exit status, so a failed validation shows as a failed run.
+
+## Out of scope
+
+- Baking configs into the image, persistent disk/caching across runs, scheduled
+  recurring validation of a fixed server, and any name-based key/agency
+  inference.
+
+## Verification
+
+All exercised against the live KCM/Puget Sound config (public sample key
+`org.onebusaway.iphone`):
+
+- `make docker-build` builds clean.
+- **Render path:** `docker run --rm oba-validator "$(printf '%s' '<compact-json>' | base64)"`
+  produces a full report — exercising base64 decode + the validator, and
+  confirming CA certs / outbound HTTPS work. Exit code propagates through the
+  `exec` (validation failure → 1).
+- **Render-override simulation:** the same with `--entrypoint /app/entrypoint.sh`
+  (Render names `entrypoint.sh` as the executable) produces the same report.
+- **Local ergonomics:** `docker run --rm oba-validator '<compact-json>'` (raw,
+  `{`-prefixed) is passed through and produces a report.
+- **Flags:** `... <base64> --json` emits JSON.
+- **Failure modes:** no argument → exit 2 (usage); a non-base64, non-`{`
+  argument → loud `base64` decode error and non-zero exit (no silent
+  fallthrough).

entrypoint.sh

@@ -0,0 +1,28 @@
+#!/bin/sh
+# Render runs a one-off job's startCommand by splitting it on whitespace and
+# passing the result as argv — there is no shell, so quotes are not stripped and
+# a JSON config cannot be passed inline (it has spaces and special characters).
+# Callers therefore base64-encode the compact config JSON into a single token:
+#
+#   startCommand: /app/entrypoint.sh <base64-config-json> [validator-flags...]
+#
+# This script decodes that token and hands the raw JSON to the validator as its
+# sole positional argument. A raw JSON argument (one starting with "{") is passed
+# through unchanged, which keeps local `docker run` ergonomic; base64 strings
+# never start with "{", so the two cases are unambiguous. Any extra arguments are
+# forwarded to the validator as flags (which must precede the config).
+set -eu
+
+if [ "$#" -eq 0 ]; then
+	echo "usage: entrypoint.sh <base64-config-json | raw-json> [flags...]" >&2
+	exit 2
+fi
+
+arg="$1"
+shift
+case "$arg" in
+	'{'*) config="$arg" ;;
+	*)    config="$(printf '%s' "$arg" | base64 -d)" ;;
+esac
+
+exec /app/oba-validator "$@" "$config"

render.yaml

@@ -0,0 +1,14 @@
+# Render Blueprint: deploy oba-validator as a Docker cron job that effectively
+# never runs on its own. Trigger real validations as one-off jobs against this
+# service, passing the whole config (including apiKey) as a base64-encoded start
+# command: `/app/entrypoint.sh <base64-config>`. See "Deploying to Render" in the
+# README.
+services:
+  - type: cron
+    name: oba-validator
+    runtime: docker
+    dockerfilePath: ./Dockerfile
+    # Feb 29 02:00 UTC — fires at most once every ~4 years, i.e. virtually never.
+    schedule: "0 2 29 2 *"
+    # Cron jobs are not available on the free tier; adjust to taste.
+    plan: starter