Configuration

Overview

The configuration is split into two files:

• server.toml — server-level settings: API, Web UI, database, WASM, logging, HTTP servers, etc.
• deployment.toml — component arrays: activities, workflows, webhook endpoints, and cron tasks.

Version Compatibility

The obelisk-version field can be set in either file to ensure compatibility with the running Obelisk version:

obelisk-version = "0.37"

Built-in Defaults

All three servers start automatically with built-in defaults — no server.toml is required unless you need to change addresses, database settings, or other server-level options:

• API server at 127.0.0.1:5005
• Web UI at 127.0.0.1:8080
• External webhook server at 127.0.0.1:9090

Running the Server

obelisk server run --deployment deployment.toml
obelisk server verify --deployment deployment.toml

# With explicit server config:
obelisk server run --server-config server.toml --deployment deployment.toml
obelisk server verify --server-config server.toml --deployment deployment.toml

If --server-config is omitted, built-in defaults are used. If --deployment is omitted, the database's active/enqueued deployment is used.

Server Configuration (server.toml)

API Server

api.listening_addr = "127.0.0.1:5005"   # Address and port for API server

Web UI

webui.listening_addr = "127.0.0.1:8080" # Address and port for web UI

Warning: Listening on all interfaces ([::]:<port>) is not recommended as authentication is not yet implemented.

Sqlite

Set SQLite database directory.

database.sqlite.directory = "${DATA_DIR}/obelisk-sqlite"

See Path Prefixes for how ${DATA_DIR} is translated.

Customize PRAGMA statements. Defaults are in crates/db-sqlite/src/sqlite_dao.rs

database.sqlite.pragma = { "cache_size" = "10000", "synchronous" = "FULL" }

PostgreSQL

Configure connection to Postgres. All of the following keys support environment variable interpolation.

database.postgres.host =     "${POSTGRES_HOST}"
database.postgres.user =     "${POSTGRES_USER}"
database.postgres.password = "${POSTGRES_PASSWORD}"
database.postgres.db_name =  "${POSTGRES_DATABASE}"

Database creation

database.postgres.provision_policy = "never" # One of "auto"|"never".

If auto is selected, missing database will be created on startup.

Timers Watcher Configuration

[timers_watcher]
enabled = true
leeway.milliseconds = 500
tick_sleep.milliseconds = 100

Global WASM Configuration

[wasm]
cache_directory = "${CACHE_DIR}/wasm"          # WASM file cache location
backtrace.persist = true                       # Persist backtraces on effect calls for all workflows and webhook endpoints.
allocator_config = "auto"                      # One of "auto"|"on_demand"|"pooling"
global_executor_instance_limiter = "unlimited" # If set to an integer, limits the number of concurrent workflow and activity executions.
global_webhook_instance_limiter = "unlimited"  # If set to an integer, limits the number of concurrent webhook requests.
fuel = "unlimited"                             # If set to an integer, WASM instances consume fuel, details: https://docs.wasmtime.dev/api/wasmtime/struct.Store.html#method.set_fuel
parallel_compilation = true                    # Enable (default) or disable parallel AOT compilation of each WASM component.

See Path Prefixes for how ${CACHE_DIR} is translated.

WASM Cache Directory

Path to directory where downloaded or transformed WASM files are stored. Supports path prefixes. By default "${CACHE_DIR}/wasm" or "./cache/wasm" if no valid home directory path could be retrieved from the operating system.

Allocator Configuration

See Allocation strategy for instance creation. Can be either pooling or on demand. Default value auto will attempt to use the pooling strategy with a fallback on error to on_demand.

Code Generation Cache

The compiled binaries can be stored to speed up startup time.

[wasm.codegen_cache]
enabled = true
directory = "${CACHE_DIR}/codegen"   # Path to directory where AOT generated code is cached. Supports path prefixes.

Global Workflow Configuration

[workflows]
lock_extension_leeway.milliseconds = 100         # Starts extending the lock a little before it expires, specifically at expires_at minus the configured leeway.

HTTP Servers

The built-in "external" HTTP server is always available at 127.0.0.1:9090 and does not need to be declared. Define additional named servers in server.toml when you need non-default ports:

[[http_server]]
name = "server_name"                  # Server identifier
listening_addr = "0.0.0.0:9000"       # Listen address and port
max_inflight_requests = "unlimited"   # Concurrent request limit

Named servers defined here can be referenced from webhook_endpoint_wasm entries in deployment.toml via http_server = "server_name".

Observability

Levels and filtering is configured using EnvFilter syntax.

OTLP Tracing

[otlp]
enabled = true
level = "info,app=trace"   # See filtering syntax
service_name = "obelisk-server"
otlp_endpoint = "http://localhost:4317"

Logging

Console Logging

[log.console]
enabled = false
level = "info,app=debug"   # See filtering syntax
style = "plain_compact"    # One of "plain"|"plain_compact"|"json"
span = "none"              # One of "none"|"new"|"enter"|"exit"|"close"|"active"|"full"
target = false             # Whether to include the target module in message
writer = "stderr"          # One of "stderr"|"stdout". Default: "stderr"

File Logging

[log.file]
enabled = false
level = "info,obeli=debug,app=debug" # See filtering syntax
style = "json"             # One of "plain"|"plain_compact"|"json"
span = "close"             # One of "none"|"new"|"enter"|"exit"|"close"|"active"|"full"
target = true              # Whether to include the target module in message
rotation = "daily"         # One of "minutely"|"hourly"|"daily"|"never"
directory = "."
prefix = "obelisk_server_daily" # File name prefix

Deployment Configuration (deployment.toml)

The deployment file contains only component arrays. All server-level settings must go in server.toml.

Common Component Settings

All WASM components (Activities, Workflows, Webhooks) share these configuration options:

name = "component_name"                         # Required: Component identifier
location = "path/to/wasm"                       # File path location
location = "oci://docker.io/repo/image:tag"     # OCI registry location (note the oci:// prefix)

Value of location supports path prefixes when used as a file path.

Note: The location field uses a single string. oci:// references an OCI image; plain paths without a prefix are treated as local file paths. Both WASM and JS components can be stored in OCI registries — see obelisk component push to publish them.

Common Executor Settings

exec.batch_size = 5                            # Executions per event loop tick
exec.lock_expiry.seconds = 1                   # Execution lock duration
exec.tick_sleep.milliseconds = 200             # Executor sleeps the specified duration when polling for pending executions
exec.locking_strategy = "auto"                 # Workflow default. See supported strategies below.
exec.instance_limiter = "unlimited"            # If set to an integer, limits concurrent executions for this executor. Default: "unlimited"

Workflows support all three locking strategies:

• auto (default) selects executions by exported FFQNs. After a redeployment, an in-progress execution is replayed against the current workflow component. If replay succeeds, Obelisk upgrades the execution and associates it with the current deployment. If replay detects nondeterminism, the execution stays on its previous component version and is not repeatedly retried against the incompatible digest. The upgrade outcome is recorded in the execution history.
• by_ffqns selects executions by the FFQNs exported by the component, without automatically upgrading their component assignment.
• by_component_digest selects only executions assigned to the exact component version (by sha256 digest) that was available when the execution was first submitted. Such an execution can be upgraded using the upgrade API endpoint or gRPC RPC. The RPC attempts to replay the execution log by default to avoid upgrading to incompatible workflow code.

Activities support by_ffqns (default) and by_component_digest, but not auto. Since activities are restarted and not replayed, the default by_ffqns strategy lets pending executions use the new code after redeployment without an upgrade.

Activities

WASM Activities

Configure each WASM activity component using the activity_wasm section:

[[activity_wasm]]
name = "..."
location = "oci://..."
# Common component and executor settings apply
max_retries = 5                      # Maximum retry attempts
retry_exp_backoff.milliseconds = 100 # Initial retry delay (doubles each attempt)
forward_stdout = "db"                # stdout forwarding ("db"|"stdout"|"stderr"|"none"). Default: "db"
forward_stderr = "db"                # stderr forwarding ("db"|"stdout"|"stderr"|"none"). Default: "db"
env_vars = ["ENV1", "ENV2=value"]    # Environment variable configuration. Inherit from system if value is not provided.
logs_store_min_level = "debug"       # Minimum log level to persist in the database. One of "off"|"trace"|"debug"|"info"|"warn"|"error". Default: "debug"

Permanent Error Handling

Activities returning a variant containing a case named permanent will skip retries, regardless of max_retries.

Outbound HTTP Allowlist

Activities that make outbound HTTP calls require explicit [[allowed_host]] entries. Without them, all outbound HTTP is blocked.

[[activity_wasm]]
name = "activity_llm"
location = "..."
exec.lock_expiry.seconds = 10
env_vars = [{key = "API_BASE_URL", value = "${API_BASE_URL:-https://api.openai.com}"}]

[[activity_wasm.allowed_host]]
pattern = "${API_BASE_URL:-https://api.openai.com}"
methods = ["POST"]

[activity_wasm.allowed_host.secrets]
env_vars = ["OPENAI_API_KEY"]
replace_in = ["headers"]

Pattern supports wildcards: "*" matches all HTTPS hosts on port 443, "*://*" matches any host on default ports, "*.example.com" matches subdomains. The pattern field supports ${VAR} and ${VAR:-default} env var interpolation.

Secrets are injected via placeholder replacement in outgoing HTTP requests. WASM receives an opaque placeholder; the runtime substitutes real values only for requests to approved hosts.

JavaScript Activities

[[activity_js]]
name = "name"
location = "path/to/source.js"          # Local path or oci://registry/image:tag
ffqn = "namespace:package/interface@version.function"  # Required
params = [                               # Optional, defaults to no parameters
  { name = "param1", type = "string" },
  { name = "count", type = "u32" },
]
return_type = "result"                   # Defaults to "result". Must be result, result<T>, result<T, string>, or result<T, variant{...}>
max_retries = 5
retry_exp_backoff.milliseconds = 100
forward_stdout = "db"
forward_stderr = "db"
logs_store_min_level = "debug"

Outbound HTTP allowlist: same [[activity_js.allowed_host]] syntax as activity_wasm.

Exec Activities

Exec activities run a native executable (shell script, Python script, Docker command, etc.) as a durable activity. The child process receives function parameters as JSON-encoded CLI arguments. The result is read from stdout — exit code 0 means success, non-zero means error. Both stdout and stderr are streamed and persisted, available via the CLI, REST API, and Web UI.

[[activity_exec]]
name = "name"                                # Optional. Defaults to {ifc_name}.{function_name} from ffqn
location = "${DEPLOYMENT_DIR}/scripts/my-script.sh" # Local path or oci://registry/image:tag
# content = '''#!/usr/bin/env bash
# echo "\"hello\""
# '''
# content_digest = "sha256:..."
ffqn = "namespace:package/interface.function" # Required
params = [
  { name = "a", type = "u32" },
  { name = "b", type = "u32" },
]
return_type = "result<u32, string>"          # See return type conventions below
max_retries = 5
retry_exp_backoff.milliseconds = 100
forward_stdout = "db"                        # One of "none"|"stdout"|"stderr"|"db". Default: "db"
forward_stderr = "db"
logs_store_min_level = "debug"
max_output_bytes = 4096                      # Max bytes from stdout for the response. Default: 4096

Exactly one of location or content must be set:

• location can point to a local script file or an oci://... reference.
• Local files are read at deploy time and converted into embedded content, making the deployment self-contained.
• content embeds the script directly in deployment.toml.
• content_digest can be used to pin and verify the resolved script contents.

Environment variables and secrets

# Only listed vars are exposed; host environment is cleared
env_vars = ["PATH", {key = "MY_VAR", value = "my_value"}]

# Secrets: resolved at startup and piped to stdin as JSON {"KEY":"value",...}
[activity_exec.secrets]
env_vars = [{name = "MY_SECRET", value = "${HOST_SECRET_VAR}"}]

Return type conventions

The return_type field must be one of:

• result — no return data; exit 0 = ok, non-zero = error
• result<T> — stdout is parsed as JSON value of type T on success
• result<T, string> — on error, stderr is captured as the error string
• result<T, variant { execution-failed, ... }> — structured error type where execution-failed is a variant case

T can be _ to indicate no ok value (e.g. result<_, string>). In this case stdout is ignored.

Retry and timeout

Exec activities follow the same retry semantics as WASM and JS activities. The exec.lock_expiry setting controls how long the child process is allowed to run before being killed — the execution is then retried or marked as permanently timed out.

Stub Activities

[[activity_stub]]
name = "..."
location = "oci://..."

Inline mode (no WASM file required):

[[activity_stub]]
name = "my-stub"                             # Optional. Defaults to {ifc_name}.{function_name} from ffqn
ffqn = "namespace:package/interface.function"
params = [{ name = "id", type = "u64" }]
return_type = "result<string, string>"

External Activities

[[activity_external]]
name = "..."
location = "oci://..."

Inline mode (no WASM file required):

[[activity_external]]
name = "my-external-activity"                # Optional. Defaults to {ifc_name}.{function_name} from ffqn
ffqn = "namespace:package/interface.function"
params = [{ name = "id", type = "u64" }]
return_type = "result<string, string>"

Workflows

WASM Workflows

Configure each workflow component using the workflow_wasm section:

[[workflow_wasm]]
name = "..."
location = "oci://..."
# Common component and executor settings apply
retry_exp_backoff.milliseconds = 100  # Initial retry delay

# Blocking strategy:
blocking_strategy = "await"           # One of ("await"|"interrupt"|{"kind"=...})
# Default strategy is await.
# Customize the number of non-blocking events that can be cached and written in a batch.
# blocking_strategy = { kind = "await", non_blocking_event_batching = 100 }

# Map from frame symbol file names to corresponding file paths on local filesystem.
# Both sides can use path prefixes.
backtrace.sources = {"backtracepath/src/lib.rs"="localpath/src/lib.rs"}

# Stub WASI CLI world imports. Only needed for workflows authored in TinyGo.
stub_wasi = false                     # Default is false.

## Automatic lock extension can be disabled by setting the duration to zero.
lock_extension.seconds = 1

logs_store_min_level = "debug"       # Minimum log level to persist in the database. Default: "debug"

The blocking strategy controls whether an execution should await the child execution response or be interrupted and later replayed. Note that the await strategy will only wait until lock_expiry duration expires.

JavaScript Workflows

[[workflow_js]]
name = "name"
location = "path/to/workflow.js"       # Local path or oci://registry/image:tag
ffqn = "namespace:package/interface@version.function"  # Required
params = [                             # Optional
  { name = "param1", type = "string" },
]
return_type = "result"
retry_exp_backoff.milliseconds = 100
lock_extension = true
blocking_strategy = "await"
logs_store_min_level = "debug"

Webhook Endpoints

A Webhook Endpoint must be associated with a HTTP Server and must define one or more routes to listen on. Routes are divided into two categories: with HTTP methods (high priority) and without HTTP methods (low priority). When a request matches multiple routes of the same priority, the first webhook will receive it.

The built-in "external" HTTP server (at 127.0.0.1:9090 by default) is always available and used when http_server is omitted. Additional named servers are defined in server.toml.

WASM Webhook Endpoints

[[webhook_endpoint_wasm]]
name = "..."
location = "oci://..."
# Common component settings apply
http_server = "server_name"          # Optional: reference to a named HTTP server in server.toml. Defaults to built-in "external" server.
routes = [                           # Route configurations
    { methods = ["GET"], route = "/path" },
    "/other/*",
    "/status/:param1/:param2"
]
forward_stdout = "db"                # stdout forwarding ("db"|"stdout"|"stderr"|"none"). Default: "db"
forward_stderr = "db"                # stderr forwarding ("db"|"stdout"|"stderr"|"none"). Default: "db"
env_vars = ["ENV1", "ENV2=value"]    # Environment variable configuration. Inherit from system if value is not provided.
# Map from frame symbol file names to corresponding file paths on local filesystem.
# Both sides can use path prefixes.
backtrace.sources = {"backtracepath/src/lib.rs"="localpath/src/lib.rs"}

JavaScript Webhook Endpoints

[[webhook_endpoint_js]]
name = "name"
location = "path/to/webhook.js"
http_server = "external"             # Optional: defaults to built-in "external" server
routes = [{ methods = ["GET"], route = "/some"}, "/other"]
forward_stdout = "stderr"
forward_stderr = "stderr"
logs_store_min_level = "debug"
env_vars = ["ENV1", "ENV2=value"]

Route Syntax

Routes: Define URL paths (only the path is matched):

Static paths

• "/" - Root path only
• "/path" - Exact path match

Wildcards

• "/path/*" - Path prefix match
• "{ methods = ["GET"], route = "/path" }" - Method-specific (priority) match

Parameterized

• "/status/:param1/:param2" - Path parameters (exposed as env vars)

All paths

• "" or "/*" - Match all paths

Cron (Periodic Tasks)

Cron tasks trigger a function on a recurring schedule or once at startup. They are defined directly in deployment.toml:

[[cron]]
name = "my-daily-job"
ffqn = "myapp:tasks/jobs@1.0.0.daily-cleanup"
params = '["arg1", 42]'                  # JSON array; defaults to []
schedule = "@daily"                      # cron expression or named shorthand

The schedule field accepts standard five-field cron expressions ("0 3 * * *") or one of the named shorthands:

See Cron tasks for a full explanation of the scheduling model.

Path Prefixes

The following path prefixes are supported:

In deployment.toml:

In server.toml:

Note: the resolved path on Mac OS and Windows will be different, e.g. for ${CONFIG_DIR}:

• /Users/youruser/Library/Application Support/com.obelisk.obelisk-App/ on Mac
• C:\Users\youruser\AppData\Roaming\obelisk\obelisk\config\ on Windows

See the directories crate documentation for details.