github.com/hugh712/snapd@v0.0.0-20200910133618-1a99902bd583/overlord/configstate/configcore/runwithstate.go (about)

     1  // -*- Mode: Go; indent-tabs-mode: t -*-
     2  // +build !nomanagers
     3  
     4  /*
     5   * Copyright (C) 2020 Canonical Ltd
     6   *
     7   * This program is free software: you can redistribute it and/or modify
     8   * it under the terms of the GNU General Public License version 3 as
     9   * published by the Free Software Foundation.
    10   *
    11   * This program is distributed in the hope that it will be useful,
    12   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    13   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    14   * GNU General Public License for more details.
    15   *
    16   * You should have received a copy of the GNU General Public License
    17   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    18   *
    19   */
    20  
    21  package configcore
    22  
    23  import (
    24  	"fmt"
    25  	"strings"
    26  
    27  	"github.com/snapcore/snapd/overlord/configstate/config"
    28  	"github.com/snapcore/snapd/release"
    29  )
    30  
    31  func init() {
    32  	// Most of these handlers are no-op on classic.
    33  	// TODO: consider allowing some of these on classic too?
    34  	// consider erroring on core-only options on classic?
    35  
    36  	coreOnly := &flags{coreOnlyConfig: true}
    37  
    38  	// capture cloud information
    39  	addWithStateHandler(nil, setCloudInfoWhenSeeding, nil)
    40  
    41  	// proxy.{http,https,ftp}
    42  	addWithStateHandler(validateProxyStore, handleProxyConfiguration, coreOnly)
    43  
    44  	// resilience.vitality-hint
    45  	addWithStateHandler(validateVitalitySettings, handleVitalityConfiguration, nil)
    46  
    47  	// XXX: this should become a FSOnlyHandler. We need to
    48  	// add/implement Changes() to the ConfGetter interface
    49  	// store-certs.*
    50  	addWithStateHandler(validateCertSettings, handleCertConfiguration, nil)
    51  
    52  	validateOnly := &flags{validatedOnlyStateConfig: true}
    53  	addWithStateHandler(validateRefreshSchedule, nil, validateOnly)
    54  	addWithStateHandler(validateRefreshRateLimit, nil, validateOnly)
    55  	addWithStateHandler(validateAutomaticSnapshotsExpiration, nil, validateOnly)
    56  }
    57  
    58  type withStateHandler struct {
    59  	validateFunc func(config.Conf) error
    60  	handleFunc   func(config.Conf, *fsOnlyContext) error
    61  	configFlags  flags
    62  }
    63  
    64  func (h *withStateHandler) validate(cfg config.ConfGetter) error {
    65  	conf := cfg.(config.Conf)
    66  	if h.validateFunc != nil {
    67  		return h.validateFunc(conf)
    68  	}
    69  	return nil
    70  }
    71  
    72  func (h *withStateHandler) handle(cfg config.ConfGetter, opts *fsOnlyContext) error {
    73  	conf := cfg.(config.Conf)
    74  	if h.handleFunc != nil {
    75  		return h.handleFunc(conf, opts)
    76  	}
    77  	return nil
    78  }
    79  
    80  func (h *withStateHandler) needsState() bool {
    81  	return true
    82  }
    83  
    84  func (h *withStateHandler) flags() flags {
    85  	return h.configFlags
    86  }
    87  
    88  // addWithStateHandler registers functions to validate and handle a subset of
    89  // system config options requiring to access and manipulate state.
    90  func addWithStateHandler(validate func(config.Conf) error, handle func(config.Conf, *fsOnlyContext) error, flags *flags) {
    91  	if handle == nil && (flags == nil || !flags.validatedOnlyStateConfig) {
    92  		panic("cannot have nil handle with addWithStateHandler if validatedOnlyStateConfig flag is not set")
    93  	}
    94  	h := &withStateHandler{
    95  		validateFunc: validate,
    96  		handleFunc:   handle,
    97  	}
    98  	if flags != nil {
    99  		h.configFlags = *flags
   100  	}
   101  	handlers = append(handlers, h)
   102  }
   103  
   104  func Run(cfg config.Conf) error {
   105  	// check if the changes
   106  	for _, k := range cfg.Changes() {
   107  		switch {
   108  		case strings.HasPrefix(k, "core.store-certs."):
   109  			if !validCertOption(k) {
   110  				return fmt.Errorf("cannot set store ssl certificate under name %q: name must only contain word characters or a dash", k)
   111  			}
   112  		case !supportedConfigurations[k]:
   113  			return fmt.Errorf("cannot set %q: unsupported system option", k)
   114  		}
   115  	}
   116  
   117  	for _, h := range handlers {
   118  		if err := h.validate(cfg); err != nil {
   119  			return err
   120  		}
   121  	}
   122  
   123  	for _, h := range handlers {
   124  		if h.flags().coreOnlyConfig && release.OnClassic {
   125  			continue
   126  		}
   127  		if err := h.handle(cfg, nil); err != nil {
   128  			return err
   129  		}
   130  	}
   131  	return nil
   132  }