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* re-arrange the user docs * Minor description edit * update styles * fix service links Co-authored-by: kn0wmad <kn0wmad@protonmail.com> Co-authored-by: Lucy Cifferello <12953208+elvece@users.noreply.github.com>
112 lines
3.7 KiB
ReStructuredText
112 lines
3.7 KiB
ReStructuredText
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.. _config_rules:
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============
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Config Rules
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============
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This file defines the configuration rules, or the rule-set that defines dependencies between config variables. In practice, config rules are for auto-configuring self dependencies. Self dependencies are internal dependencies of a service, such as if the setting of one config variable informs the option of another setting. These "dependencies" are configured as rules.
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A rule is a boolean expression that we demand to be true. It is not true if the expression fails the rule parser. Set of predicates. xt
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They follow the `Backus–Naur <https://en.wikipedia.org/wiki/Backus%E2%80%93Naur_form>`_ meta-syntax for writing rules.
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Rules are composed of two main concepts:
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* Variables - accessor into a configuration
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* Terms - either a variable or type literal (ie. a boolean term is a boolean variable, a boolean expression, or a comparison operation between numbers or strings)
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Variables can be booleans, numbers, or strings, and have a different syntax depending on the type. These type annotations check your config rules against your config spec and throw an error if invalid.
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- ``?`` - Casts to boolean value. If the value is not a boolean, this notes whether or not the value is null.
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- ``#`` - Treat the value as a number. If it is not a number, the value will be parsed as NaN. String numbers are not currently supported.
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- ``'`` - Cast the value into a string. Applies to any value except for an object or a list.
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- ``!`` - Equals not.
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.. note::
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Config rules are processed in order.
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If application does not satisfy a rule, a set of suggestions should be provided. These suggestions are in the form of the operation to preform:
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- ``Set`` - set the value
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- ``Push`` - add to the value (such as to a list)
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- ``Delete`` - delete the value
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.. code:: typescript
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enum SuggestionVariant = Set | Delete | Push
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interface Set {
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var: String, // fully qualified path without typecast
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// one of the following three variants are required
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to: Option<String> // a string expression, use when tying another config value
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to-value: Option<String>
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to-entropy: Option<{
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charset: String (eg. 'a-z,A-Z,0-9')
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len: Number
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}>
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}
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interface Delete {
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src: String, // path to key - removes if in a list
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}
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interface Push {
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to: String,
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value: String, // string literal of value to be set
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}
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SET Examples
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------------
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.. code:: yaml
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- SET:
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# the key in config you want to set
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var: 'users.[first(item => ''item.name = "c-lightning")].password'
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# the value in config that you will set
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to-entropy:
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charset: "a-z,A-Z,0-9"
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len: 22
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- SET:
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var: 'users.[first(item => ''item.name = "c-lightning")].fetch-blocks'
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to-value: true
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PUSH Examples
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-------------
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.. code:: yaml
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- PUSH:
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to: "users"
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value:
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name: c-lightning
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allowed-calls: []
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- PUSH:
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to: 'users.[first(item => ''item.name = "c-lightning")].allowed-calls'
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value: "getnetworkinfo"
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Full example from `c-lightning manifest <https://github.com/Start9Labs/c-lightning-wrapper/blob/master/manifest.yaml>`_:
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.. code:: yaml
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config:
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- rule: '''users.*.name = "c-lightning"'
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description: 'Must have an RPC user named "c-lightning"'
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suggestions:
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- PUSH:
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to: "users"
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value:
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name: c-lightning
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allowed-calls: []
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- SET:
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var: 'users.[first(item => ''item.name = "c-lightning")].password'
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to-entropy:
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charset: "a-z,A-Z,0-9"
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len: 22
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