snapd/docs/meta.md

Package metadata

This document describes the meta data of a snappy package. All files are located under the meta/ directory.

The following files are supported:

readme.md

The readme.md file contains a description of the snap. The snappy tools will automatically extract the heading as the short summary for the snap and the first paragraph as the description in the store.

package.yaml

This file describes the snap package and is the most important file for a snap package. The following keys are mandatory:

• name: the name of the snap (only [a-z0-9][a-z0-9+-])
• version: the version of the snap (only [a-zA-Z0-9.+~-] are allowed)
• vendor: the vendor of the snap

The following keys are optional:

• icon: a SVG icon for the snap that is displayed in the store

• explicit-license-agreement: set to Y if the user needs to accept a special meta/license.txt before the snap can be installed

• license-version: a string that, when it changes and explicit-license-agreement is Y, prompts the user to accept the license again.

• type: (optional) the type of the snap, can be:

  • app - the default if empty
  • oem - a special snap that OEMs can use to customize snappy for their hardware
  • framework - a specialized snap that extends the system that other snaps may use

• architectures: (optional) a yaml list of supported architectures ["all"] if empty

• frameworks: a list of the frameworks the snap needs as dependencies

• services: the servies (daemons) that the snap provides

  • name: (required) name of the service (only [a-zA-Z0-9+.-])
  • description: (required) description of the service
  • start: (required) the command to start the service
  • stop: (optional) the command to stop the service
  • stop-timeout: (optional) the time in seconds to wait for the service to stop
  • poststop: a command that runs after the service has stopped
  • caps: (optional) list of additional security policies to add. See security.md for details
  • security-template: (optional) alternate security template to use instead of default. See security.md for details
  • security-override: (optional) high level overrides to use when security-template and caps are not sufficient. See security.md for details
  • security-policy: (optional) hand-crafted low-level raw security policy to use instead of using default template-based security policy. See security.md for details
  • ports: (optional) define what ports the service will work
    • internal: the ports the service is going to connect to
      • tagname: a free form name
        • port: (optional) number/protocol, e.g. 80/tcp
        • negotiable: (optional) Y if the app can use a different port
    • external: the ports the service offer to the world
      • tagname: a free form name, some names have meaning like "ui"
        • port: (optional) see above
        • negotiable: (optional) see above
  • bus-name: (optional) message bus connection name for the service. May only be specified for snaps of 'type: framework' (see above). See frameworks.md for details.

• binaries: the binaries (executables) that the snap provides

  • name: (required) the name of the binary, the user will be able to call it as $name.$pkgname (only [a-zA-Z0-9+.-])
  • exec: the program that gets executed (can be omited if name points to a binary already)
  • caps: (optional) see entry in services (above)
  • security-template: (optional) see entry in services (above)
  • security-override: (optional) see entry in services (above)
  • security-policy: (optional) see entry in services (above)

license.txt

A license text that the user must accept before the snap can be installed.

hooks/ directory

See config.md for details.

Examples

See lp:~snappy-dev/snappy-hub/snappy-examples for up-to-date examples.