Stirling-PDF on Google Cloud Run

Stirling-PDF is an open-source (MIT-licensed core), locally-hosted web PDF toolkit — merge, split, convert, OCR, compress, watermark, sign, redact, and 50+ other PDF operations, all processed on your own infrastructure so documents never touch a third-party service. This module deploys Stirling-PDF on Cloud Run v2 on top of the App_CloudRun foundation, which provisions and manages the shared Google Cloud infrastructure.

This guide focuses on the cloud services Stirling-PDF uses and how to explore and operate them from the Google Cloud Console and the command line. For the mechanics common to every Cloud Run application — service identity, ingress and load balancing, scaling and concurrency, CI/CD, Cloud Armor, IAP, Binary Authorization, VPC Service Controls, and the deployment lifecycle — refer to the App_CloudRun foundation guide rather than repeating them here.

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What Stirling-PDF costs on RAD, and how that compares

Stirling-PDF on RAD's Cloud Run module costs about US$19.16 a month in a Google Cloud project you own, with the module fee charged once in RAD credits. Stirling-PDF is stateless with no database, so this is the cheapest configuration on the platform's Cloud Run side. For the lowest running cost it stays here; GKE Autopilot is only worth it if it needs to sit beside other Kubernetes workloads — see the GKE guide for that option, at about US$45.68 a month instead. If you only need it occasionally — a batch of documents, a one-off conversion job — a RAD-managed project can be deleted and restored within 30 days for a handful of credits (under US$1) instead of paying for it to sit idle. See Pause it for free, below. Figures are as at 8 October 2026; sources are listed at the end of this section.

What you pay on RAD

	In a Google Cloud project you own	In a project RAD manages for you
Module fee, once per deployment	40 credits (US$4 at the top-up price)	36 credits (10% lower)
Build time	About 3-6 credits per build	The same
Google Cloud running cost	Billed by Google to your own billing account, about US$19.16 a month for the default configuration (table below)	Metered hourly in credits; RAD publishes 3 credits a day, about 90 a month
Who owns what	You own the project and its billing; RAD deploys and updates it	RAD owns the project, with guardrails, quotas and budget alerts; you get console access, and a minimum purchased balance is held in reserve

10 credits cost US$1 on a one-off top-up, and less on a monthly plan. In a project RAD manages, the network is shared by every application in the project, so a second application does not add a second set of it.

Default running cost in your own project (us-central1, Google list prices):

Resource (module default)	Per month
Cloud Run, 1x vCPU / 2 GiB (scaleToZero)	US$13.16
Cloud NAT and networking	US$5.00
Cloud Storage (add-ons, backups)	US$1.00
Total	US$19.16

How it compares

• Stirling PDF's own hosted plan, Stirling PDF Team, costs $99/month for up to 100 users on its hosted SaaS — a per-organisation fee aimed at teams, not infrastructure cost (source: stirling.com/pricing). RAD's own-project figure is a small fraction of that because it's the raw Cloud Run compute cost with no per-seat software fee layered on.
• A self-managed comparison: Hetzner CPX22 (2 vCPU/4GB) runs about $24/month, a DigitalOcean 2 vCPU/4GB Droplet is the same $24/month, and a GCP Compute Engine e2-standard-2 (2 vCPU/8GB) is about $49/month — all more than RAD's own-project Cloud Run figure, and all need to be kept patched by hand, which RAD's managed Secret Manager and monitoring otherwise cover.
• With no database and no persistent state, Stirling-PDF is close to the floor of what any deployment on RAD costs — almost the whole bill is the Cloud Run container itself.

Pause it for free: delete a RAD-managed project, restore it when you need it

If Stirling-PDF runs in a project RAD manages for you, deleting the whole project unlinks its billing first, then asks Google to delete the project outright — Google's own 30-day recoverable soft delete. Unlike deleting one module, this does not tear down the compute resource one by one: the whole project simply stops, and nothing is charged while it waits, because billing is already unlinked.

Restoring, within 30 days and only by the project's owner, asks Google to undelete the project and reattaches its billing account, then asks you to run Update on each deployment to confirm everything came back. Because nothing was individually destroyed, that Update finds the same resources already there — it is a check, not a rebuild, and an Update never charges the module fee again. This costs only a handful of credits (under US$1) in total for a typical 2-3-deployment chain.

What this needs: you must own the project (not one RAD only manages billing for), you must restore it yourself within 30 days — after that Google deletes it for good — and restoring is admitted like creating a new project, so your purchased credit balance must still clear the tier's floor (100 credits for the sandbox tier most study/demo use fits). Google says most services are fully working again within 36 hours of a restore.

One real gap: nightly backups are written to a bucket inside the project, and that bucket has Cloud Storage's soft-delete explicitly turned off, so it is very likely gone as soon as you delete the project — even though the project itself is recoverable for 30 days. Stirling-PDF itself holds no database, so for a default install with nothing irreplaceable in it, this does not matter.

Pay only while you use it, the other way: delete and redeploy

In your own project, or once the 30-day restore window has passed, the alternative is to delete Stirling-PDF outright and redeploy it later. A redeploy costs the module fee again, plus the builds — roughly 45 credits (about US$4.50) in your own project, or 41 credits in a RAD-managed one.

Deleting saves money only once Stirling-PDF would otherwise sit unused long enough to clear that redeploy cost against its own daily running cost — against the own-project total above (about US$0.64 a day), that works out to about 8 days or more, or about 14 days or more in a RAD-managed one (3 credits a day). There's no database here, so deleting this app frees its entire running cost rather than just a share of it.

Keep data first: anything Stirling-PDF writes to a backup bucket inside the deployment is deleted with it, so copy anything you want to keep out before deleting.

Lab sessions and Managed Environments

• Lab sessions, for training: a trainer runs a session for a class. Each participant gets the app in their own Google Cloud project for 15 minutes to 24 hours, within an allowance the trainer sets. Either the trainer funds every place, or each participant pays for their own. Everything is deleted when the session ends and unused credits go back to the trainer.
• Managed Environments, for consultancies: a partner runs the app for a client from a ring-fenced wallet it funds, and settles with the client directly. If the wallet runs low, billing pauses and the data is kept, so nobody receives an unexpected charge. At the end the partner hands the project over and the deployments become the client's own.
• Credits can be bought in more than 20 currencies, including XAF, XOF, NGN, GHS, KES and ZAR, by card, bank transfer or mobile money.

Sources (8 October 2026): Google Cloud Billing Catalog API list prices; radmodules.dev/pricing for RAD's own fees and daily-credit estimates; Delete and restore projects for the pause/restore mechanics; stirling.com/pricing for Stirling PDF Team's hosted price.

1. Overview

Stirling-PDF runs as a Java / Spring Boot container (with a bundled LibreOffice for document conversions) on Cloud Run v2. The deployment wires together a deliberately small set of Google Cloud services — Stirling-PDF is stateless, so there is no database, no persistent storage, and no secrets to manage:

Capability	Google Cloud service	Notes
Compute	Cloud Run v2	Java service, 1 vCPU / 2 GiB by default, serverless autoscaling; scale-to-zero enabled
Container image	Artifact Registry	Official stirlingtools/stirling-pdf image, mirrored in by default
Ingress	Cloud Run URL / Cloud Load Balancing	Default run.app URL; optional external HTTPS load balancer + custom domain
Redis (inert)	Redis	Off by default. enable_redis only makes the Foundation inject REDIS_* env vars — Stirling-PDF never reads them, so this provides no rate limiting or bot detection
Observability	Cloud Logging / Cloud Monitoring	Container logs, metrics, optional uptime check and alerts

Sensible defaults worth knowing up front:

• Stateless — no database, no storage, no secrets. database_type = "NONE", no GCS buckets, no NFS, and an empty secret map. Every PDF operation runs in a per-request ephemeral working directory that is discarded on completion.
• Prebuilt image. container_image_source = "prebuilt" deploys the official stirlingtools/stirling-pdf image directly; enable_image_mirroring = true mirrors it into Artifact Registry to avoid Docker Hub rate limits.
• Login is disabled by default. enable_login = false (SECURITY_ENABLELOGIN=false) ships an open instance. Enable it and front the service with IAP or Cloud Armor for a private deployment.
• Request-based billing + scale-to-zero. cpu_always_allocated = false and min_instance_count = 0 — CPU is billed only while serving a request, and the service scales to zero when idle. A cold start adds a few seconds of JVM warm-up.
• 2 GiB memory floor. The JVM plus LibreOffice needs at least 2Gi; raise memory_limit for heavy OCR / conversion workloads.
• Public ingress by default. ingress_settings = "all" so the toolkit is reachable at its run.app URL. Combine with IAP for identity-gated access.
• Health probes hit /api/v1/info/status — a public, unauthenticated endpoint that returns 200 once the JVM and LibreOffice have initialised (~70s first-boot window).

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2. Google Cloud Services & How to Explore Them

All commands assume PROJECT and REGION are set. Service and resource names are reported in the deployment Outputs.

A. Cloud Run — the Stirling-PDF service

Stirling-PDF runs as a Cloud Run v2 service that autoscales by request load between the minimum (0) and maximum instance counts. Each deployment creates an immutable revision; traffic can be split across revisions for safe rollouts.

• Console: Cloud Run → select the service for revisions, traffic, logs, and metrics.
• CLI:

  gcloud run services list --project "$PROJECT" --region "$REGION"
  gcloud run services describe <service-name> --project "$PROJECT" --region "$REGION"
  gcloud run revisions list --service <service-name> --project "$PROJECT" --region "$REGION"

See App_CloudRun for scaling, concurrency, execution environment, and traffic splitting.

B. Artifact Registry — the container image

The official stirlingtools/stirling-pdf image is mirrored into Artifact Registry (enable_image_mirroring = true) and Cloud Run pulls it from there. No Cloud Build step runs — the image is prebuilt upstream.

• Console: Artifact Registry → Repositories.
• CLI:

  gcloud artifacts repositories list --project "$PROJECT" --location "$REGION"
  gcloud artifacts docker images list <repo-path> --project "$PROJECT"

See App_CloudRun for the mirroring mechanism and image retention.

C. Networking & ingress

The service is reachable at its run.app URL by default (ingress_settings = "all"). An external HTTPS load balancer with a custom domain, Cloud CDN, and Cloud Armor can be layered on; ingress settings and VPC egress control connectivity.

• Console: Cloud Run (service URL); Network services → Load balancing.
• CLI:

  gcloud run services describe <service-name> --region "$REGION" --format='value(status.url)'
  gcloud compute addresses list --project "$PROJECT"

See App_CloudRun.

D. Redis (inert — enable_redis has no application effect)

Redis is disabled by default (enable_redis = false). Setting enable_redis = true only makes the App_CloudRun foundation inject REDIS_HOST/REDIS_PORT/ REDIS_AUTH env vars into the container — Stirling-PDF never reads them. stirlingpdf.tf's own comment confirms "no DB or Redis", and neither StirlingPDF_Common nor this module maps those env vars into any Stirling-PDF-recognized setting. Enabling Redis does not implement rate limiting or bot detection for this application; there is no supported way to add that behaviour to Stirling-PDF through this module. Use enable_cloud_armor for actual abuse mitigation on a public instance.

• CLI (to confirm the env vars are present but unused):

  gcloud run services describe <service-name> --region "$REGION" \
    --format='value(spec.template.spec.containers[0].env)'

E. Identity-Aware Proxy (optional)

Because Stirling-PDF processes potentially sensitive documents, a private deployment should gate access with IAP. Enabling enable_iap requires an authenticated, authorized Google identity before any request reaches the service — no VPN or Stirling-PDF login configuration needed.

• Console: Security → Identity-Aware Proxy.
• CLI:

  gcloud iap web get-iam-policy --resource-type=backend-services --project "$PROJECT"

See App_CloudRun for the IAP wiring.

F. Cloud Logging & Monitoring

Container logs flow to Cloud Logging; Cloud Run metrics flow to Cloud Monitoring, with optional uptime checks and alert policies.

• Console: Logging → Logs Explorer; Monitoring → Dashboards / Alerting.
• CLI:

  gcloud run services logs read <service-name> --project "$PROJECT" --region "$REGION" --limit 50

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3. Stirling-PDF Application Behaviour

• Nothing is persisted. Uploads are written to a per-request ephemeral working directory and deleted when the response is returned. There is no database and no bucket — a redeploy or scale event loses nothing because there is nothing to lose.
• Slow first boot. Spring Boot plus LibreOffice initialisation takes tens of seconds. The startup probe targets /api/v1/info/status and allows up to ~70 seconds (10s initial delay + 6 × 10s) before the revision is marked unhealthy.
• Login is optional and off by default. enable_login = false ships an open instance. Set enable_login = true to require Stirling-PDF's built-in authentication; combine with IAP for defence in depth.
• Version upgrades are image-tag bumps. Because the image is unmodified upstream and there is no schema, changing application_version rolls out a new revision with no migration step.
• Large files and long conversions. Raise memory_limit and timeout_seconds for large documents or heavy OCR; set SYSTEM_MAXFILESIZE via environment_variables to cap upload size.
• Confirm the running configuration:

  gcloud run services describe <service-name> --region "$REGION" --project "$PROJECT" \
    --format='value(spec.template.spec.containers[0].env)'

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4. Configuration Variables

Variables are grouped exactly as they appear on the deployment platform. Only settings specific to or notable for Stirling-PDF are listed; every other input is inherited from App_CloudRun with its standard behaviour.

Group 1 — Project & Identity

Variable	Default	Description
project_id	(required)	Target Google Cloud project.
region	us-central1	Region for the service and regional resources.

Group 2 — Deployment Environment

Variable	Default	Description
tenant_id	demo	Short suffix that makes resource names unique per environment.
support_users	[]	Emails granted project access and monitoring alerts.
resource_labels	{}	Labels applied to all resources.

Group 3 — Application Identity

Variable	Default	Description
application_name	stirlingpdf	Base name for resources. Do not change after first deploy.
display_name	Stirling-PDF	Human-readable name shown in the Console.
application_version	latest	Stirling-PDF image tag; pin to a specific release in production.
enable_login	false	Enable Stirling-PDF's built-in auth (SECURITY_ENABLELOGIN).
default_locale	en-US	Default UI locale (SYSTEM_DEFAULTLOCALE).

Group 4 — Runtime & Scaling

Variable	Default	Description
deploy_application	true	Set false to provision infrastructure only.
container_image_source	prebuilt	Deploy the official image (prebuilt) or build a custom one.
cpu_limit	1000m	CPU per instance.
memory_limit	2Gi	Memory per instance; 2Gi floor for JVM + LibreOffice.
cpu_always_allocated	false	Request-based billing — Stirling-PDF has no background work.
min_instance_count	0	Fixed at 0 (scale-to-zero) — the module hardcodes this value; the variable is not forwarded to the Foundation and cannot be changed.
max_instance_count	3	Autoscaling upper bound (safe to raise — no shared state).
container_port	8080	Stirling-PDF listens on port 8080.
execution_environment	gen2	Gen2 recommended.
timeout_seconds	60	Maximum request duration; raise for large conversions.
enable_cloudsql_volume	false	Not used — Stirling-PDF has no database.
enable_image_mirroring	true	Mirror the image into Artifact Registry.
traffic_split	[]	Split traffic across revisions for staged rollouts.

Group 5 — Access & Ingress Control

Variable	Default	Description
ingress_settings	all	all for public access; internal-and-cloud-load-balancing behind an LB.
vpc_egress_setting	PRIVATE_RANGES_ONLY	Route only RFC 1918 traffic via VPC.
enable_iap	false	Require Google sign-in. Recommended for private/sensitive-document instances.
iap_authorized_users / iap_authorized_groups	[]	Who may access through IAP.

Group 6 — Environment Variables & Secrets

Variable	Default	Description
environment_variables	{}	Extra Stirling-PDF settings (e.g. SYSTEM_MAXFILESIZE). Login and locale are set via enable_login / default_locale.
secret_environment_variables	{}	Secret Manager references. Stirling-PDF needs none by default.
secret_propagation_delay	30	Seconds to wait after secret creation before proceeding.
secret_rotation_period	2592000s	Secret Manager rotation notification frequency.

Group 7 — Backup & Restore

Stirling-PDF is stateless, so backup inputs (backup_schedule, backup_retention_days, enable_backup_import, backup_source, backup_uri, backup_format) have no application data to protect. Left at defaults.

Group 8 — CI/CD & Binary Authorization

Standard App_CloudRun Cloud Build / Cloud Deploy integration — see App_CloudRun. Key inputs: enable_cicd_trigger, github_repository_url, github_token, enable_cloud_deploy, enable_binary_authorization.

Group 10 — Load Balancer, CDN & Image Retention

Variable	Default	Description
enable_cloud_armor	false	Provision Global HTTPS LB + Cloud Armor WAF. Recommended for public instances.
admin_ip_ranges	[]	CIDR ranges exempted from WAF rules.
application_domains	[]	Custom domain names for the HTTPS LB.
enable_cdn	false	Enable Cloud CDN on the HTTPS LB backend.
max_images_to_retain / delete_untagged_images / image_retention_days	(set)	Artifact Registry cleanup policy.

Group 11 — Storage & Filesystem

Variable	Default	Description
create_cloud_storage	false	Stirling-PDF is stateless — no bucket by default.
storage_buckets	[]	Optional additional GCS buckets.
enable_nfs	false	NFS off by default; enable only if co-locating Redis on the NFS server.
gcs_volumes	[]	GCS Fuse volume mounts (requires gen2).
manage_storage_kms_iam / enable_artifact_registry_cmek	false	CMEK options.

Group 12 — Database Backend

Variable	Default	Description
database_type	NONE	Fixed — Stirling-PDF uses no database.
database_password_length	32	Not used.
enable_auto_password_rotation / rotation_propagation_delay_sec	off	Not applicable.

Group 14 — Observability & Health

Variable	Default	Description
startup_probe	HTTP /api/v1/info/status, 10s delay, 6 retries	Startup probe. ~70s first-boot window for JVM + LibreOffice.
liveness_probe	HTTP /api/v1/info/status, 15s delay	Liveness probe.
uptime_check_config	{ enabled=false, path="/api/v1/info/status" }	Cloud Monitoring uptime check.
alert_policies	[]	Metric alert policies.

Group 21 — Redis (inert Foundation passthrough)

Variable	Default	Description
enable_redis	false	Inert for Stirling-PDF: only makes App_CloudRun inject REDIS_HOST/REDIS_PORT/REDIS_AUTH env vars, which the application never reads. No rate limiting or bot detection results from enabling this.
redis_host	""	Redis endpoint. Leave empty to use the NFS server IP. Unused by Stirling-PDF regardless of value.
redis_port	6379	Redis port. Unused by Stirling-PDF regardless of value.
redis_auth	""	Optional Redis auth password (sensitive). Unused by Stirling-PDF regardless of value.

Group 22 — VPC Service Controls & Audit Logging

Variable	Default	Description
enable_vpc_sc	false	Enforce a VPC-SC perimeter (requires organization_id).
vpc_cidr_ranges / vpc_sc_dry_run	(set)	Access level CIDRs / dry-run mode.
enable_audit_logging	false	Detailed Cloud Audit Logs.

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5. Outputs

Returned on a successful deployment — the quickest way to locate and explore the running resources.

Output	Description
service_name	Cloud Run service name.
service_url	Default run.app URL of the service.
service_location	Region the service runs in.
stage_services	Stage-specific service URLs (Cloud Deploy).
load_balancer_ip / load_balancer_url	External HTTPS load balancer IP / URL (when enabled).
storage_buckets	Created Cloud Storage buckets (empty — Stirling-PDF is stateless).
network_name / network_exists / regions	VPC network, presence, regions.
container_image / container_registry	Deployed image and Artifact Registry repo.
monitoring_enabled / monitoring_notification_channels / uptime_check_names	Monitoring status, channels, uptime checks.
deployment_id / tenant_id / resource_prefix	Naming identifiers.
project_id / project_number	Project identifiers.
cicd_enabled / github_repository_url / cicd_configuration	CI/CD status and details.
artifact_registry_repository / cloudbuild_trigger_name	Registry and build trigger.
vpc_sc_enabled / vpc_sc_perimeter_name / vpc_sc_dry_run_mode	VPC-SC status.
audit_logging_enabled / artifact_registry_cmek_enabled	Audit logging and CMEK status.

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6. Configuration Pitfalls & Sensible Defaults

Risk: Critical (data loss / outage / security) — High (service degraded) — Medium (cost or partial degradation) — Low (minor).

Inherited plan-time validation. This module passes its configuration through the App_CloudRun foundation engine, which validates values and combinations at plan time — IAP with no authorized identities, a gen1 runtime with NFS/GCS mounts, an out-of-range redis_port/timeout_seconds, a memory below the gen2 floor. Invalid configuration fails the plan with a clear, named error before any resource is created, so most mistakes below are caught up front rather than at apply or runtime.

Setting	Sensible value	Risk	Consequence if wrong
enable_login + ingress	enable_login = true or IAP for private use	High	Default enable_login = false + public ingress leaves an open PDF toolkit anyone with the URL can use.
enable_iap	Enable for sensitive-document instances	High	Without IAP (and with login off) the service is unauthenticated; users can upload confidential documents to an open endpoint.
memory_limit	2Gi	High	Below ~2Gi the JVM + LibreOffice OOM-kills during conversions; gen2 also rejects < 512Mi at plan time.
timeout_seconds	60, raise for big files	High	Large OCR/conversion jobs exceeding the timeout return 504 mid-operation.
startup_probe window	Keep the ~70s default	Medium	Shortening the initial delay / failure threshold marks the revision unhealthy before LibreOffice finishes warming up.
enable_cloud_armor	Enable for public instances	Medium	A public toolkit without a WAF is exposed to abuse and automated scanning.
enable_redis	Leave false — it is inert for this application	Low	Enabling it only adds unused REDIS_* env vars to the revision; Stirling-PDF never reads them, so it provides no rate limiting or bot detection. Use enable_cloud_armor instead for actual abuse mitigation.
min_instance_count	0 (fixed)	Low	Scale-to-zero adds a few seconds of JVM warm-up on the first request after idle. The module hardcodes min_instance_count = 0 — the variable is not forwarded, so it cannot be raised to 1 to eliminate cold starts.
SYSTEM_MAXFILESIZE (via environment_variables)	Set a sane cap	Low	Unbounded uploads let a single large file consume the instance's memory.

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For the foundation behaviour referenced throughout — service identity, scaling and concurrency, ingress and load balancing, CI/CD, Cloud Armor, IAP, Binary Authorization, VPC-SC, and image mirroring — see App_CloudRun. Stirling-PDF-specific application configuration shared with the GKE variant is described in StirlingPDF_Common.

Related guides

• Hands-on lab: Stirling-PDF on Cloud Run — deploy it step by step, with the console screens and commands at each stage.
• Stirling-PDF on GKE Autopilot — the same application on Kubernetes, for when you need the other deployment target.
• Stirling-PDF Common — Shared Application Configuration — the configuration shared by both deployment targets.
• Deployed alongside Outline on Google Cloud Run, BookStack on Google Cloud Run, Paperless-ngx on Google Cloud Run in the Knowledge Base & Documentation solution.