NCM::download - NCM download configuration component


  • Configure()

    Returns error in case of failure.


Downloads files onto the local machine during the configuration, and optionally post-processes the files. The download is achieved by invoking "curl", so any URLs acceptable to curl (including local URL's) are allowed.


  • /software/components/download/active : boolean

    Activates/deactivates the component.

  • /software/components/download/proto : string

    The default protocol to use for any sources which do not specify the protocol.

  • /software/components/download/server : string

    The default server hostname to use for any sources which do not specify the source.

  • /software/components/download/proxyhosts : list

    A list of strings. Each string should be a hostname (and possibly with ':port' suffix). If this is specifed, then a reverse proxy configuration is assumed for all of the file source. Whenever a file is downloaded, each of the proxy hosts will be used first before attempting the original source URL. The first proxy host to respond will be used for all subsequent download attempts.

  • /software/components/download/files : nlist

    An nlist keyed by the escaped filename that is required for the destination file. The value associated with each key should be an nlist containing the following values:

    • href

      A URL (either absolute, or relative) that describes the source of the file. The URL can be specified as relative by ommitting the server name and/or the protocol, in which case the component defaults will be used. Local files can be used as source, such as file://localhost/etc/foo.txt or even file:///etc/foo.txt.

    • post

      If specified, then the value will be used as a command to run whenever the file is updated. Note that if the update is optimised away by the download process (e.g. if the file is already up-to-date), the command will still be executed, so it is the responsibility of this command to determine what work needs to be done, if any.

    • gssapi

      If true, then curl will be invoked with GSSAPI Negotiate extension enabled, using the host keytab as the identity.

    • proxy

      If false, then the proxy configuration will be ignored for this file. This defaults to true. This has no effect when there are no proxy hosts defined.

    • perm

      If defined, sets the permissions of the file to the defined permissions (defined in octal, e.g. 0644).

    • owner

      If defined, sets the ownership to given user (name or number).

    • group

      If defined, sets the group ownership to the given group (name or number).

    • min_age

      The minimum number of minutes old that the file must be to be considered valid for download (defaults to 0);


The component download modifies only the files specified within the configuration.


"/software/components/download/active" = true;
"/software/components/download" = nlist(
      "server", "",
      "proto",  "http",
"/software/components/download/files" = npush(
      escape("/etc/passwd"), nlist(
               "href", "",
               "post", "/usr/local/mk_passwd"
"/software/components/download/files" = npush(
      escape("/usr/local/foo.txt"), nlist(
               "href", "file:///etc/foo.txt",
               "owner", "john",
               "perm", "0400"