src/helper/ChildConfig.h

   1 /*
   2  * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef _SQUID_SRC_HELPER_CHILDCONFIG_H
  10 #define _SQUID_SRC_HELPER_CHILDCONFIG_H
  11
  12 namespace Helper
  13 {
  14
  15 /**
  16  * Contains statistics of a particular type of child helper.
  17  *
  18  * Some derived from a helper children configuration option,
  19  * some from runtime stats on the currently active children.
  20  */
  21 class ChildConfig
  22 {
  23 public:
  24     ChildConfig();
  25     explicit ChildConfig(const unsigned int m);
  26
  27     /**
  28      * When new helpers are needed call this to find out how many more
  29      * we are allowed to start.
  30      * \retval 0       No more helpers may be started right now.
  31      * \retval N < 0   Error. No more helpers may be started.
  32      * \retval N       N more helpers may be started immediately.
  33      */
  34     int needNew() const;
  35     void parseConfig();
  36
  37     /**
  38      * Update an existing set of details with new start/max/idle/concurrent limits.
  39      * This is for parsing new child settings into an object incrementally then updating
  40      * the running set without losing any of the active state or causing races.
  41      */
  42     ChildConfig &updateLimits(const ChildConfig &rhs);
  43
  44     /* values from squid.conf */
  45 public:
  46
  47     /** maximum child process limits. How many of this helper the system can cope with */
  48     unsigned int n_max;
  49
  50     /**
  51      * Number of children to kick off at startup.
  52      * set via the startup=N option.
  53      *
  54      * By default if undefined 1 will be started immediately for use.
  55      * The minimum/idle amount will be scheduled for starting as soon as possible after startup is completed.
  56      */
  57     unsigned int n_startup;
  58
  59     /**
  60      * Number of helper children to keep available as a buffer against sudden bursts of requests.
  61      * set via the idle=N option. May be zero.
  62      *
  63      * The default value for backward compatibility the default for this is the same as maximum children.
  64      * For now the actual number of idle children is only reduced by a reconfigure operation. This may change.
  65      */
  66     unsigned int n_idle;
  67
  68     /**
  69      * How many concurrent requests each child helper may be capable of handling.
  70      * Default: 0  - no concurrency possible.
  71      */
  72     unsigned int concurrency;
  73
  74     /* derived from active operations */
  75
  76     /**
  77      * Total helper children objects currently existing.
  78      * Produced as a side effect of starting children or their stopping.
  79      */
  80     unsigned int n_running;
  81
  82     /**
  83      * Count of helper children active (not shutting down).
  84      * This includes both idle and in-use children.
  85      */
  86     unsigned int n_active;
  87
  88     /**
  89      * The requests queue size. By default it is of size 2*n_max
  90      */
  91     unsigned int queue_size;
  92
  93     /// how to handle a serious problem with a helper request submission
  94     enum SubmissionErrorHandlingAction {
  95         actDie, ///< kill the caller process (i.e., Squid worker)
  96         actErr  ///< drop the request and send an error to the caller
  97     };
  98     /// how to handle a new request for helper that was overloaded for too long
  99     SubmissionErrorHandlingAction onPersistentOverload;
 100
 101     /**
 102      * True if the default queue size is used.
 103      * Needed in the cases where we need to adjust default queue_size in
 104      * special configurations, for example when redirector_bypass is used.
 105      */
 106     bool defaultQueueSize;
 107
 108     /// older stateful helper server reservations may be forgotten
 109     time_t reservationTimeout = 64; // reservation-timeout
 110 };
 111
 112 } // namespace Helper
 113
 114 /* Legacy parser interface */
 115 #define parse_HelperChildConfig(c)     (c)->parseConfig()
 116 #define dump_HelperChildConfig(e,n,c)  storeAppendPrintf((e), "\n%s %d startup=%d idle=%d concurrency=%d\n", (n), (c).n_max, (c).n_startup, (c).n_idle, (c).concurrency)
 117 #define free_HelperChildConfig(dummy)  // NO.
 118
 119 #endif /* _SQUID_SRC_HELPER_CHILDCONFIG_H */
 120