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1.15.7 • Public • Published


Execution engine for executable documents

Build Status Code coverage NPM


npm install --global @stencila/executa


All configuration options can be set, in descending order of priority, by:

  • a command line argument e.g. --<value> <value>
  • an environment variable prefixed with EXECUTA_ e.g. EXECUTA_<option>=<value>
  • a .json or .ini configuration file, set using the --config option, or .executarc by default
Name Description Type Validators Default
debug Display debug log data? boolean false
stdio Start a stdio server. boolean false
vsock Start a vsock server.1 `boolean number`
tcp Start a TCP server.2 `boolean string` pattern: `/^((tcp?://)?([^:/]+)(:(d+))?(/(.+))?)
http Start a HTTP server.3 `boolean string` pattern: `/^((https?://)?([^:/]+)(:(d+))?(/(.+))?)
ws Start a WebSocket server.4 `boolean string` pattern: `/^((wss?://)?([^:/]+)(:(d+))?(/(.+))?)
timeout Duration of inactivity after which the process should stop.5 number 0
timelimit Maximum duration for the process.6 number 0
peers List of peer addresses.7 string[] ["stdio://*"]
queueLength Maximum length of the request queue.8 number minimum: 0 1000
queueInterval Interval between attempts to reduce request queue.9 number exclusiveMinimum: 0 1
queueStale Duration after which a request is removed from queue.10 number exclusiveMinimum: 0 3600
  1. If a number, it will be used as the port number. If true, the default Vsock port 6000 will be used.
  2. If a string, it will be parsed and used as the address of the TCP server. If true, the default TCP address tcp:// will be used.
  3. If a string, it will be parsed and used as the address of the HTTP server. If true, the default HTTP address will be used.
  4. If a string, it will be parsed and used as the address of the WebSocket server. If true, the default WebSocket address ws:// will be used.
  5. Seconds. Zero means no timeout.
  6. Seconds. Zero means no time limit.
  7. Each string in this list is parsed as an address to a peer executor. e.g., docker://image
  8. When queue reaches this length, subsequent requests will fail with an error response to client.
  9. Seconds.
  10. Seconds. Client will be notified when a request is removed.


Testing with the REPL

There is an interactive REPL that can be used with the both query and execute CLI commands e.g.

npm run cli -- execute --repl --debug

Testing in the browser

  1. Serve Executa over HTTP (to provide static HTML) and WebSocket (to provide JSON RPC):

    npm run cli:dev -- serve --http --ws

The :dev suffix to cli uses ts-node-dev which will restart the process when any source files change.

  1. Visit http://localhost:8000 in your browser and play around with the <stencila-code-chunk> WebComponent that is connected to the Executa WebSocket that you just started.

Debug inspecting

There is a NPM script, cli:debug, that can be useful for debugging the CLI, for example, from within VSCode (which will auto attach to the Node process), e.g.

npm run cli:debug -- serve --http

The :debug suffix to cli enables the Node debug inspector so you can use your favorite IDE to attach to the CLI and step through the code.


Why is @types/ws a production dependency?

This package has several dependents e.g @stencila/basha. If @types/ws is not installed as a production dependency, when you try to build dependent packages, you get the error "Cannot find type definition file for 'ws'.". By having it as a production dependency here, each dependent package does not have to install it as a development dependency.




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