Gokapi on GKE Autopilot

Gokapi is a lightweight, self-hosted file-sharing server written in Go — a self-hosted alternative to WeTransfer. Users upload files and generate shareable download links with optional expiry dates, download-count limits, and password protection, all backed by an internal SQLite database (no external database required). This module deploys Gokapi on GKE Autopilot on top of the App_GKE foundation, which provisions and manages the shared Google Cloud and Kubernetes infrastructure.

This guide focuses on the cloud services Gokapi uses and how to explore and operate them from the Google Cloud Console and the command line. For the mechanics that are common to every GKE application — Workload Identity, ingress, autoscaling, CI/CD, Cloud Armor, IAP, Binary Authorization, VPC Service Controls, backups, and the deployment lifecycle — refer to the App_GKE foundation guide rather than repeating them here.

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1. Overview

Gokapi runs as a single Go binary workload with no external database. The deployment wires together a small, focused set of Google Cloud services:

Capability	Google Cloud service	Notes
Compute	GKE Autopilot	A single-container StatefulSet pod on port 53842, 1000m CPU / 1Gi memory by default
Database / metadata	None (internal SQLite)	No Cloud SQL — Gokapi writes its own SQLite DB under GOKAPI_CONFIG_DIR; database_type is fixed to NONE
File persistence	GKE block PVC (StatefulSet)	The SQLite DB and uploaded files both live under /data, on a per-pod Persistent Volume Claim by default
Object storage	Cloud Storage (conditional)	A storage bucket is always declared, but only mounted (via GCS FUSE) when the StatefulSet PVC is disabled
Secrets	Secret Manager	Only an optional operator API key (GOKAPI_API_KEY); no mandatory generated secret
Ingress	Kubernetes Gateway API	enable_custom_domain = true by default, so a public Gateway endpoint (and reserved static IP) is provisioned out of the box

Sensible defaults worth knowing up front:

• No Cloud SQL, ever. database_type is hard-fixed to NONE by Gokapi_Common — all the generic database variables (db_name, db_user, application_database_name, etc.) are forwarded to the foundation only for variable-mirroring compatibility and have no effect.
• SQLite + uploaded files live on a real block PVC by default, not GCS FUSE. stateful_pvc_enabled = true by default, which also auto-resolves workload_type to StatefulSet (no need to set both). A 20Gi standard-rwo (SSD) PVC is mounted at /data; GOKAPI_CONFIG_DIR=/data/config (config + the SQLite database) and GOKAPI_DATA_DIR=/data/data (uploaded files) both live under that mount, so both survive pod restarts/redeploys. This matters because SQLite is not safe on gcsfuse — the module explicitly avoids that combination by disabling the GCS volume whenever the PVC is enabled (see below).
• The storage GCS bucket is still created by default even though it isn't mounted. Gokapi_Common always declares a storage-suffixed bucket, and create_cloud_storage = true by default provisions it — but with the default StatefulSet PVC in place, enable_gcs_storage_volume is automatically set to false to avoid a double-mount at /data, so the bucket sits unused unless you disable stateful_pvc_enabled.
• Single replica by design. min_instance_count = 1, max_instance_count = 1. Gokapi's SQLite database is single-writer; there is no distributed/clustered mode, so do not scale beyond 1 pod.
• No admin password is auto-generated. Gokapi has no mandatory secret — the administrator account is created interactively through Gokapi's own first-run setup wizard the first time you open the service in a browser.
• Optional operator API key. enable_api_key (default false) generates a 32-character random token, stores it in Secret Manager, and injects it as GOKAPI_API_KEY via a native Kubernetes Secret (explicit_secret_values) rather than the Secret Manager → SecretSync path. This is a convenience token only — Gokapi's own upload/download API keys are normally minted from the admin UI after setup.
• Redis is force-disabled. The variant hardcodes enable_redis = false to the foundation regardless of the enable_redis variable's value — Gokapi has no use for Redis.
• A public endpoint is provisioned out of the box. Unlike many app modules, enable_custom_domain defaults to true and reserve_static_ip defaults to true, even though service_type defaults to ClusterIP. This gives Gokapi a working public Gateway endpoint by default — appropriate for an app whose whole purpose is generating shareable download links. See App_GKE for the default <reserved-ip>.nip.io hostname mechanic.

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2. Google Cloud Services & How to Explore Them

All commands assume you have run gcloud container clusters get-credentials <cluster> --region <region> --project <project> and that PROJECT, REGION, and NAMESPACE are set. The namespace and other identifiers are reported in the deployment Outputs.

A. GKE Autopilot — the Gokapi workload

Gokapi runs as a single-pod StatefulSet by default (stable pod identity, an OrderedReady restart policy, and a per-pod PVC). Autopilot bills for the CPU and memory the pod actually requests.

• Console: Kubernetes Engine → Workloads → select the Gokapi workload for pods, revisions, and events.
• CLI:

  kubectl get pods,svc,statefulset -n "$NAMESPACE"
  kubectl logs -n "$NAMESPACE" statefulset/<service-name> --tail=100
  kubectl describe pod -n "$NAMESPACE" -l app=<service-name>

See App_GKE for how Autopilot, scaling, and the StatefulSet vs Deployment workload type are managed.

B. Persistent storage — the block PVC (and the unused GCS bucket)

The SQLite metadata database and every uploaded file live under /data on a per-pod block PVC (stateful_pvc_enabled = true, 20Gi, standard-rwo/SSD by default). A storage Cloud Storage bucket is also declared and — unless you turn the PVC off — provisioned but never mounted.

• Console: Kubernetes Engine → Storage for the PVC; Cloud Storage → Buckets for the (likely unused) bucket.
• CLI:

  kubectl get pvc -n "$NAMESPACE"
  gcloud storage buckets list --project "$PROJECT" --filter="name~storage"

See App_GKE for the StatefulSet/PVC mechanics (Group 7) and the SSD SSD_TOTAL_GB quota consideration on quota-constrained projects.

C. Secret Manager

Gokapi creates no mandatory secret. The only secret this module can create is the optional GOKAPI_API_KEY operator convenience token, gated by enable_api_key (default false).

• Console: Security → Secret Manager.
• CLI:

  gcloud secrets list --project "$PROJECT" --filter="name~api-key"
  gcloud secrets versions access latest --secret=<api-key-secret-name> --project "$PROJECT"

See App_GKE for the Secret Store CSI / native-secret injection model and rotation.

D. Networking & ingress

enable_custom_domain = true and reserve_static_ip = true are both defaults, so a Kubernetes Gateway API resource with a reserved static external IP is provisioned automatically, even though the underlying Kubernetes Service itself defaults to ClusterIP.

• Console: Network services → Load balancing; VPC network → IP addresses.
• CLI:

  kubectl get svc,gateway,httproute -n "$NAMESPACE"
  gcloud compute addresses list --project "$PROJECT"

See App_GKE for the default <reserved-ip>.nip.io hostname, custom domains, Cloud CDN, and static IP details.

E. Cloud Logging & Monitoring

Pod stdout/stderr flow to Cloud Logging; GKE metrics flow to Cloud Monitoring. Optional uptime checks and alert policies are available (uptime_check_config is disabled by default).

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

  gcloud logging read 'resource.type="k8s_container" AND resource.labels.namespace_name="'"$NAMESPACE"'"' \
    --project "$PROJECT" --limit 50

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3. Gokapi Application Behaviour

• No initialization job runs by default. Gokapi_Common supplies no default initialization_jobs entry — Gokapi manages its own storage and needs no database to bootstrap. Only user-supplied jobs (for custom data loading or migration) will appear under Kubernetes Jobs.
• First-boot setup is entirely interactive. There is no auto-install flag and no generated admin password. The first time you open the service in a browser, Gokapi's own setup wizard creates the administrator account.
• Where data physically persists. With the default stateful_pvc_enabled = true, both GOKAPI_CONFIG_DIR=/data/config (the SQLite metadata DB and app config) and GOKAPI_DATA_DIR=/data/data (uploaded files) sit on the same per-pod block PVC mounted at /data. If you instead set stateful_pvc_enabled = false, the module automatically re-enables the GCS FUSE mount of the storage bucket at the same path — acceptable for light use, but higher latency for SQLite-heavy workloads than the block PVC.
• Single-writer, single-pod. min_instance_count = 1 / max_instance_count = 1 by default. Gokapi's SQLite database has no clustering/replication story, so do not raise max_instance_count above 1.
• Health probes hit the public root, no auth required. Both the startup probe and the liveness probe are HTTP GET / (Gokapi's login/setup page, 200, unauthenticated) — startup: initial_delay=15s, timeout=5s, period=10s, failure_threshold=10; liveness: initial_delay=30s, timeout=5s, period=30s, failure_threshold=3.
• Container port is fixed at 53842. This is Gokapi's native port, wired via GOKAPI_PORT=53842 and the module's container_port; it is not configurable through the generic container_port variable (which is documented as having no effect on this module).
• Verify the deployed pod and its persistent state:

  kubectl get pods,pvc -n "$NAMESPACE"
  kubectl exec -n "$NAMESPACE" statefulset/<service-name> -- ls -la /data/config /data/data
  kubectl logs -n "$NAMESPACE" statefulset/<service-name> --tail=50

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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 Gokapi are listed; every other input is inherited from App_GKE with its standard behaviour and defaults.

Group 3 — Application Identity

Variable	Default	Description
application_name	gokapi	Base name for resources. Do not change after first deploy.
application_version	latest	f0rc3/gokapi image tag used as the custom-build base; latest is pinned to a known-good tag (v1.9.6) at build time via the app-specific GOKAPI_VERSION build arg.
enable_api_key	false	Generates a random API key in Secret Manager and injects it as GOKAPI_API_KEY, an operator convenience token only.

Group 4 — Runtime & Scaling

Variable	Default	Description
cpu_limit	1000m	CPU limit for the Gokapi container.
memory_limit	1Gi	Memory limit; Gokapi is a lightweight Go binary and needs little memory.
min_instance_count	1	Kept at 1 to avoid cold starts.
max_instance_count	1	Keep at 1 — Gokapi's SQLite DB is single-writer with no distributed mode.
container_port	53842	Not forwarded to the foundation; Gokapi's port is fixed at 53842 via Gokapi_Common.
enable_cloudsql_volume	false	Must remain false — Gokapi has no Cloud SQL database.

Group 6 — GKE Backend & Cluster

Variable	Default	Description
service_type	ClusterIP	Internal-only Service by default; the public entry point instead comes from the Group 19 Gateway (enable_custom_domain, below).
workload_type	null → StatefulSet	Auto-resolves to StatefulSet because stateful_pvc_enabled = true by default.
session_affinity	None	Stickiness is largely moot with a single replica.

Group 7 — StatefulSet / PVC

Variable	Default	Description
stateful_pvc_enabled	true	Provisions a per-pod block PVC for the SQLite DB + uploads; strongly recommended over GCS FUSE for Gokapi.
stateful_pvc_size	20Gi	Size to hold the SQLite DB plus all uploaded files.
stateful_pvc_mount_path	/data	Both GOKAPI_CONFIG_DIR (/data/config) and GOKAPI_DATA_DIR (/data/data) live under this mount.
stateful_pvc_storage_class	standard-rwo	Balanced PD (SSD) by default on GKE Autopilot; draws the SSD_TOTAL_GB quota.
stateful_fs_group	3000	Matches Gokapi's UID 1000 / GID 2000 so the PVC is group-writable.

Group 13 — Filesystem (NFS)

Variable	Default	Description
enable_nfs	false	Off by default — Gokapi persists via the StatefulSet PVC, not shared NFS.

Group 16 — Database Backend

Variable	Default	Description
database_type	NONE	Fixed — Gokapi has no SQL database; all other database variables in this group are forwarded only for variable-mirroring compatibility and have no effect.

Group 19 — Custom Domain, Static IP & Networking

Variable	Default	Description
enable_custom_domain	true	On by default (unusual among app modules) so a public Gateway endpoint exists out of the box, matching Gokapi's purpose of generating shareable links.
reserve_static_ip	true	Stable external IP across redeploys, feeding the default <ip>.nip.io hostname.
application_domains	[]	Custom hostnames + managed certificate; layer onto the default Gateway endpoint.

All other inputs follow standard App_GKE behaviour.

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5. Outputs

These values are returned on a successful deployment and are the quickest way to locate and explore the running resources.

Output	Description
service_name	Kubernetes Service name.
namespace	Namespace the workload runs in.
service_cluster_ip	In-cluster ClusterIP.
stage_service_cluster_ips	Map of ClusterIPs for stage-specific services.
service_external_ip	External LoadBalancer IP (when a static IP is reserved).
service_url	URL to reach Gokapi.
gokapi_api_key_secret_id	Secret Manager secret ID for the optional operator API key; empty when enable_api_key is false.
storage_buckets	Created Cloud Storage buckets (the storage bucket, mounted only if the StatefulSet PVC is disabled).
network_name / network_exists / regions	VPC network, presence, available regions.
container_image / container_registry	Deployed image and Artifact Registry repo.
monitoring_enabled / monitoring_notification_channels	Monitoring status and channels.
initialization_jobs	Names of any user-supplied initialization jobs (none by default).
statefulset_name	Name of the StatefulSet.
deployment_id / tenant_id / resource_prefix	Naming identifiers.
project_id / project_number	Project identifiers.
cicd_enabled / cicd_configuration	CI/CD status and details (repo, trigger, registry).
github_repository_url / github_repository_owner / github_repository_name	CI/CD GitHub details.
artifact_registry_repository / cloudbuild_trigger_name / cloudbuild_trigger_id	Registry and build trigger.
kubernetes_ready	Whether the cluster/workload is ready.
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_GKE foundation engine, which validates values and combinations at plan time — a StatefulSet forced alongside a stateless setting, IAP with no authorized identities, quota_memory_* given as bare integers, an out-of-range container_port/backup_retention_days. 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
stateful_pvc_enabled	true	Critical	Turning it off falls back to a GCS FUSE mount for the SQLite DB — gcsfuse's write semantics are unsafe for SQLite and risk metadata corruption under real usage.
stateful_pvc_mount_path	/data (leave default)	Critical	Both GOKAPI_CONFIG_DIR and GOKAPI_DATA_DIR are computed relative to this path; changing it without matching environment_variables overrides orphans the existing SQLite DB and uploads.
max_instance_count	1	Critical	Gokapi's SQLite database is single-writer with no clustering; running >1 replica risks database corruption and inconsistent uploads.
stateful_pvc_storage_class	standard-rwo (SSD)	Medium	Fine for typical use; on a quota-constrained project (e.g. tight SSD_TOTAL_GB), override to HDD standard per App_GKE if quota is scarce — Gokapi's I/O pattern does not require SSD-level IOPS.
create_cloud_storage	true (default) with stateful_pvc_enabled = true	Medium	Creates an unused storage GCS bucket that is never mounted while the PVC is active — set create_cloud_storage = false to avoid the unnecessary bucket, or leave it if you might disable the PVC later.
enable_api_key (auto-generated secret)	Leave false unless you need a pre-provisioned key	Low	The token is a convenience only; Gokapi's real upload/download API keys are minted from the admin UI regardless of this setting.
quota_memory_requests / _limits	binary units (4Gi, 8192Mi)	Critical	Bare integers are treated as bytes and block all pod scheduling in the namespace.
enable_custom_domain / reserve_static_ip	true / true (defaults)	Medium	Disabling both leaves Gokapi reachable only via internal ClusterIP, with no public URL for the download links it generates — defeats the purpose of the app for external sharing.
enable_cloudsql_volume	false	Low	Setting it true injects a pointless Cloud SQL Auth Proxy sidecar; Gokapi never uses it.
enable_nfs	false	Low	Gokapi persists via the StatefulSet PVC by default; enabling NFS adds an unused Filestore instance unless you deliberately switch off the PVC and want shared storage instead.

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For the foundation behaviour referenced throughout — IAM and Workload Identity, autoscaling, ingress and certificates, CI/CD, Cloud Armor, IAP, Binary Authorization, VPC-SC, backups, and image mirroring — see App_GKE. Gokapi-specific application configuration shared with the Cloud Run variant is described in Gokapi_Common.