Server Configuration

The FHIR server loads its configuration with Figment, merging two sources:

let config: ServerConfig = Figment::new()
    .merge(Toml::file("haste.toml"))
    .merge(Env::prefixed("HASTE_"))
    .extract()?;

1. haste.toml — read relative to the process's working directory (backend/, when running cargo run server start from there). If the file doesn't exist, this step is silently skipped — there's no error, the server just falls through to defaults/env.
2. HASTE_-prefixed environment variables — merged after the TOML file, so environment variables win on any key set in both.

Anything left unset by either source falls back to the default listed below.

Environment Variable Naming

• Top-level fields: HASTE_<FIELD> — e.g. HASTE_API_URI, HASTE_CERTIFICATION_DIR, HASTE_MAX_REQUEST_BODY_SIZE.
• Nested sections: HASTE_<SECTION>.<field> — the prefix plus the section name, then a literal dot, then the field name exactly as it appears in TOML (lowercase) — e.g. HASTE_REPO.database_url, HASTE_SEARCH.username, HASTE_SECURITY.publicize_fhir_metadata.
• Sections that select a backend/provider via a tag (repo, search, email, security.encryption) need that tag set too, e.g. HASTE_REPO.backend=postgres.

Reference

Top level

Key	Env var	Default	Notes
api_uri	HASTE_API_URI	http://localhost:3000	Root URL the FHIR server is hosted at; used to build absolute URLs (OIDC discovery, FHIR base URLs, etc).
certification_dir	HASTE_CERTIFICATION_DIR	certifications	Directory used for JWT signing/verification key material.
admin_app_redirect_uri	HASTE_ADMIN_APP_REDIRECT_URI	http://*.localhost:3001	Redirect target for the hardcoded admin app OIDC client.
allow_artifact_mutations	HASTE_ALLOW_ARTIFACT_MUTATIONS	false	Allows mutating built-in/embedded artifact resources.
max_request_body_size	HASTE_MAX_REQUEST_BODY_SIZE	4194304 (4MB)	Max accepted request body size, in bytes.
port	HASTE_PORT	3000	Port the server listens on.

[fhir]

Key	Env var	Default
fhir.delete_limit	HASTE_FHIR.delete_limit	100 — max resources removed by a single type/system-level delete.

[repo] — resource storage backend

Tagged by backend; only postgres exists today.

Key	Env var	Default
repo.backend	HASTE_REPO.backend	postgres
repo.database_url	HASTE_REPO.database_url	postgresql://postgres:postgres@127.0.0.1/haste_health
repo.max_connections	HASTE_REPO.max_connections	20

[search] — search index backend

Tagged by backend; two backends exist: elasticsearch (the default) and postgres (search indexed in the same Postgres server as [repo], no Elasticsearch cluster required).

backend = "elasticsearch" (default):

Key	Env var	Default
search.url	HASTE_SEARCH.url	http://localhost:9200
search.username	HASTE_SEARCH.username	elastic
search.password	HASTE_SEARCH.password	elastic
search.prune_removed_search_parameters	HASTE_SEARCH.prune_removed_search_parameters	false — lets migrate search drop the mapping (and indexed data) for a removed search parameter. Off by default: removed parameters are logged, never deleted, since Elasticsearch mappings are append-only and dropping one needs a reindex.

backend = "postgres":

Key	Env var	Default
search.database_url	HASTE_SEARCH.database_url	postgresql://postgres:postgres@127.0.0.1/haste_health_search — a separate database from [repo]'s
search.max_connections	HASTE_SEARCH.max_connections	20

[email] — optional

None/absent by default (email sending disabled). Tagged by backend; only sendgrid exists today.

Key	Env var
email.backend	HASTE_EMAIL.backend (sendgrid)
email.api_key	HASTE_EMAIL.api_key
email.from_address	HASTE_EMAIL.from_address

[rate_limits]

Key	Env var	Default
rate_limits.rate_limit_subscription_tiers	HASTE_RATE_LIMITS.rate_limit_subscription_tiers	unset — a 4-element array, one limit per subscription tier (Free/Professional/Team/Unlimited).
rate_limits.rate_limit_window_seconds	HASTE_RATE_LIMITS.rate_limit_window_seconds	86400 (1 day)
rate_limits.rate_limit_operation_points	HASTE_RATE_LIMITS.rate_limit_operation_points	100

[monitoring]

Key	Env var	Default
monitoring.audit_enabled	HASTE_MONITORING.audit_enabled	false — gates the auditing middleware.
monitoring.ip_source	HASTE_MONITORING.ip_source	connect_info — one of connect_info, cf_connecting_ip, x_real_ip; how client IP is derived.

[security]

Key	Env var	Default
security.publicize_fhir_metadata	HASTE_SECURITY.publicize_fhir_metadata	true — exposes /fhir/{version}/metadata without authentication. Set to false to require auth on the capability statement.
security.aes_key	HASTE_SECURITY.aes_key	unset
security.certification_key	HASTE_SECURITY.certification_key	unset

[security.mfa]

Key	Env var	Default
security.mfa.max_credentials_per_user	HASTE_SECURITY.mfa.max_credentials_per_user	1

[security.encryption] — secret provider for aes_key / certification_key

Tagged by type: environment (default), gcp, or aws.

Key	Env var	Default
security.encryption.type	HASTE_SECURITY.encryption.type	environment
security.encryption.prefix (environment only)	HASTE_SECURITY.encryption.prefix	HASTE_SECRET_
security.encryption.project_id (gcp only)	HASTE_SECURITY.encryption.project_id	—
security.encryption.region (aws only)	HASTE_SECURITY.encryption.region	—

[operations]

Key	Env var	Default	Notes
operations.deno_pool_threads	HASTE_OPERATIONS.deno_pool_threads	Roughly half the host's available parallelism (minimum 2)	Dedicated OS threads executing custom (tenant-authored) FHIR operation scripts in isolated Deno/V8 sandboxes. Each thread runs one script at a time — this is a hard ceiling on concurrent custom-operation invocations.

Example haste.toml

api_uri = "http://localhost:3000"
certification_dir = "certifications"
admin_app_redirect_uri = "http://*.localhost:3001"
max_request_body_size = 20971520 # 20MB

[repo]
backend = "postgres"
database_url = "postgresql://postgres:postgres@localhost:5432/haste_health"
max_connections = 20

[search]
backend = "elasticsearch"
url = "http://localhost:9200"
username = "elastic"
password = "elastic"

# Alternative to the [search] block above -- no Elasticsearch cluster needed:
# [search]
# backend = "postgres"
# database_url = "postgresql://postgres:postgres@127.0.0.1/haste_health_search"
# max_connections = 20

[operations]
deno_pool_threads = 4

[monitoring]
audit_enabled = false

[security]
publicize_fhir_metadata = true
aes_key = "AES_KEY"
certification_key = "CERTIFICATE_KEY"

[security.mfa]
max_credentials_per_user = 1

[security.encryption]
type = "environment"
prefix = "HASTE_SECRET_"

Example Environment Variables (Container Deployment)

HASTE_API_URI=http://localhost:3000
HASTE_CERTIFICATION_DIR=certifications
HASTE_ADMIN_APP_REDIRECT_URI=http://*.localhost:3001

HASTE_REPO.backend=postgres
HASTE_REPO.database_url=postgresql://postgres:postgres@postgres:5432/haste_health
HASTE_REPO.max_connections=20

HASTE_SEARCH.backend=elasticsearch
HASTE_SEARCH.url=http://elasticsearch:9200
HASTE_SEARCH.username=elastic
HASTE_SEARCH.password=elastic