`app.yaml` Configuration

The app.yaml file defines the global settings for the service, including how it connects to the blockchain, how it stores data, etc.

Example `app.yaml`

# The connection string for the SQLite database.
database_url: "sqlite:data/monitor.db"

# A list of RPC endpoint URLs. Argus will cycle through these if one fails.
rpc_urls:
  - "https://eth.llamarpc.com"
  - "https://1rpc.io/eth"
  - "https://rpc.mevblocker.io"

# A unique identifier for the network being monitored.
network_id: "ethereum"

# The directory where contract ABI JSON files are located.
abi_config_path: abis/

# Controls where Argus starts on a fresh database.
# Can be a block number (e.g., 18000000), 'latest', or a negative offset (e.g., -100).
initial_start_block: -100

# Performance and reliability settings.
block_chunk_size: 5
polling_interval_ms: 10000
confirmation_blocks: 12

# API server configuration
server:
  enabled: true
  listen_address: "0.0.0.0:8080"

Configuration Parameters

Core Settings

Parameter	Description	Default
`database_url`	The connection string for the SQLite database. This field is required.	(none)
`rpc_urls`	A list of RPC endpoint URLs for the EVM network. Argus will use them in a fallback sequence if one fails. At least one URL is required.	(none)
`network_id`	A unique identifier for the network being monitored (e.g., "ethereum", "sepolia"). This field is required.	(none)
`abi_config_path`	The directory where contract ABI JSON files are located.	`abis/`
`initial_start_block`	Controls where Argus starts processing blocks on a fresh database. Can be an absolute block number (e.g., `18000000`), a negative offset from the latest block (e.g., `-100`), or the string `'latest'`.	`-100`

Performance & Reliability

Parameter	Description	Default
`block_chunk_size`	The number of blocks to fetch and process in a single batch.	`5`
`polling_interval_ms`	The interval in milliseconds to poll for new blocks.	`10000`
`confirmation_blocks`	Number of blocks to wait for before processing to protect against reorgs. A higher number is safer but introduces more latency.	`12`
`notification_channel_capacity`	The capacity of the internal channel for sending notifications.	`1024`
`shutdown_timeout`	The maximum time in seconds to wait for a graceful shutdown.	`30`
`aggregation_check_interval`	The interval in seconds to check for aggregated matches for action with policies.	`5`

Nested Configuration Sections

The following configurations are nested under their respective top-level keys in app.yaml.

Server Settings (`server`)

These settings control the built-in REST API server.

Default Configuration:

server:
  enabled: false
  listen_address: "0.0.0.0:8080"

Parameter	Description
`enabled`	Set to `true` to enable the API server. Defaults to `false` for security.
`listen_address`	The address and port for the HTTP server to listen on.

RPC Client Settings (`rpc_retry_config`)

These settings control the behavior of the client used to communicate with the EVM RPC endpoints.

Default Configuration:

rpc_retry_config:
  max_retry: 10
  backoff_ms: 1000
  compute_units_per_second: 100

Parameter	Description
`max_retry`	The maximum number of retries for a failing RPC request.
`backoff_ms`	The initial backoff delay in milliseconds for RPC retries.
`compute_units_per_second`	The number of compute units per second to allow (for rate limiting).

HTTP Client Settings (`http_retry_config`)

These settings control the retry behavior of the internal HTTP client, which is used for sending webhook notifications.

Default Configuration:

http_retry_config:
  max_retries: 3
  initial_backoff_ms: 250
  max_backoff_secs: 10
  base_for_backoff: 2
  jitter: full

Parameter	Description
`max_retries`	The maximum number of retries for a failing HTTP request.
`initial_backoff_ms`	The initial backoff delay in milliseconds for HTTP retries.
`max_backoff_secs`	The maximum backoff delay in seconds for HTTP retries.
`base_for_backoff`	The base for the exponential backoff calculation.
`jitter`	The jitter to apply to the backoff (`none` or `full`).

Rhai Script Engine Settings (`rhai`)

These settings provide guardrails for the Rhai scripts to prevent long-running or resource-intensive scripts from impacting the application's performance.

Default Configuration:

rhai:
  max_operations: 100000
  max_call_levels: 10
  max_string_size: 8192
  max_array_size: 1000
  execution_timeout: 5000

Parameter	Description
`max_operations`	Maximum number of operations a script can perform.
`max_call_levels`	Maximum function call nesting depth in a script.
`max_string_size`	Maximum size of strings in characters.
`max_array_size`	Maximum number of array elements.
`execution_timeout`	Maximum execution time per script in milliseconds.

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Argus EVM Monitor Documentation