Class: SNMP::Manager
- Inherits:
-
Object
- Object
- SNMP::Manager
- Defined in:
- lib/snmp/manager.rb
Overview
SNMP Manager
This class provides a manager for interacting with a single SNMP agent.
Example
require 'snmp'
manager = SNMP::Manager.new(:Host => 'localhost', :Port => 1061)
response = manager.get(["1.3.6.1.2.1.1.1.0", "1.3.6.1.2.1.1.2.0"])
response.each_varbind {|vb| puts vb.inspect}
manager.close
Symbolic Object Names
Symbolic names for SNMP object IDs can be used as parameters to the APIs in this class if the MIB modules are imported and the names of the MIBs are included in the MibModules configuration parameter.
See MIB.varbind_list for a description of valid parameter formats.
The following modules are loaded by default: “SNMPv2-SMI”, “SNMPv2-MIB”, “IF-MIB”, “IP-MIB”, “TCP-MIB”, “UDP-MIB”. All of the current IETF MIBs have been imported and are available for loading.
Additional modules may be imported using the MIB class. The current implementation of the importing code requires that the external ‘smidump’ tool is available in your PATH. This tool can be obtained from the libsmi website at www.ibr.cs.tu-bs.de/projects/libsmi/ .
Example
Do this once:
SNMP::MIB.import_module(MY_MODULE_FILENAME, MIB_OUTPUT_DIR)
Include your module in MibModules each time you create a Manager:
SNMP::Manager.new(:Host => 'localhost', :MibDir => MIB_OUTPUT_DIR,
:MibModules => ["MY-MODULE-MIB", "SNMPv2-MIB", ...])
Constant Summary collapse
- DefaultConfig =
Default configuration. Individual options may be overridden when the Manager is created.
{ :Host => 'localhost', :Port => 161, :TrapPort => 162, :Community => 'public', :WriteCommunity => nil, :Version => :SNMPv2c, :Timeout => 1, :Retries => 5, :Transport => UDPTransport, :MaxReceiveBytes => 8000, :MibDir => MIB::DEFAULT_MIB_PATH, :MibModules => ["SNMPv2-SMI", "SNMPv2-MIB", "IF-MIB", "IP-MIB", "TCP-MIB", "UDP-MIB"]}
- @@request_id =
RequestId.new
Instance Attribute Summary collapse
-
#config ⇒ Object
readonly
Retrieves the current configuration of this Manager.
-
#mib ⇒ Object
readonly
Retrieves the MIB for this Manager.
Class Method Summary collapse
-
.open(config = {}) ⇒ Object
Creates a Manager but also takes an optional block and automatically closes the transport connection used by this manager after the block completes.
Instance Method Summary collapse
-
#close ⇒ Object
Close the transport connection for this manager.
-
#create_trap_vb_list(sys_up_time, trap_oid, object_list) ⇒ Object
Helper method for building VarBindList for trap and inform requests.
-
#get(object_list) ⇒ Object
Sends a get request for the supplied list of ObjectId or VarBind objects.
-
#get_bulk(non_repeaters, max_repetitions, object_list) ⇒ Object
Sends a get-bulk request.
-
#get_next(object_list) ⇒ Object
Sends a get-next request for the supplied list of ObjectId or VarBind objects.
-
#get_value(object_list) ⇒ Object
Sends a get request for the supplied list of ObjectId or VarBind objects.
-
#inform(sys_up_time, trap_oid, object_list = []) ⇒ Object
Sends an inform request using the supplied varbind list.
-
#initialize(config = {}) ⇒ Manager
constructor
A new instance of Manager.
- #load_module(name) ⇒ Object
-
#next_request_id=(request_id) ⇒ Object
Set the next request-id instead of letting it be generated automatically.
-
#set(object_list) ⇒ Object
Sends a set request using the supplied list of VarBind objects.
-
#trap_v1(enterprise, agent_addr, generic_trap, specific_trap, timestamp, object_list = []) ⇒ Object
Sends an SNMPv1 style trap.
-
#trap_v2(sys_up_time, trap_oid, object_list = []) ⇒ Object
Sends an SNMPv2c style trap.
-
#walk(object_list, index_column = 0) ⇒ Object
Walks a list of ObjectId or VarBind objects using get_next until the response to the first OID in the list reaches the end of its MIB subtree.
Constructor Details
#initialize(config = {}) ⇒ Manager
Returns a new instance of Manager.
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# File 'lib/snmp/manager.rb', line 149 def initialize(config = {}) if block_given? warn "SNMP::Manager::new() does not take block; use SNMP::Manager::open() instead" end @config = DefaultConfig.merge(config) @config[:WriteCommunity] = @config[:WriteCommunity] || @config[:Community] @host = @config[:Host] @port = @config[:Port] @trap_port = @config[:TrapPort] @community = @config[:Community] @write_community = @config[:WriteCommunity] @snmp_version = @config[:Version] @timeout = @config[:Timeout] @retries = @config[:Retries] @transport = @config[:Transport].new @max_bytes = @config[:MaxReceiveBytes] @mib = MIB.new load_modules(@config[:MibModules], @config[:MibDir]) end |
Instance Attribute Details
#config ⇒ Object (readonly)
Retrieves the current configuration of this Manager.
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# File 'lib/snmp/manager.rb', line 142 def config @config end |
#mib ⇒ Object (readonly)
Retrieves the MIB for this Manager.
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# File 'lib/snmp/manager.rb', line 147 def mib @mib end |
Class Method Details
.open(config = {}) ⇒ Object
Creates a Manager but also takes an optional block and automatically closes the transport connection used by this manager after the block completes.
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# File 'lib/snmp/manager.rb', line 174 def self.open(config = {}) manager = Manager.new(config) if block_given? begin yield manager ensure manager.close end end end |
Instance Method Details
#close ⇒ Object
Close the transport connection for this manager.
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# File 'lib/snmp/manager.rb', line 188 def close @transport.close end |
#create_trap_vb_list(sys_up_time, trap_oid, object_list) ⇒ Object
Helper method for building VarBindList for trap and inform requests.
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# File 'lib/snmp/manager.rb', line 349 def create_trap_vb_list(sys_up_time, trap_oid, object_list) vb_args = @mib.varbind_list(object_list, :KeepValue) uptime_vb = VarBind.new(SNMP::SYS_UP_TIME_OID, TimeTicks.new(sys_up_time.to_int)) trap_vb = VarBind.new(SNMP::SNMP_TRAP_OID_OID, @mib.oid(trap_oid)) VarBindList.new([uptime_vb, trap_vb, *vb_args]) end |
#get(object_list) ⇒ Object
Sends a get request for the supplied list of ObjectId or VarBind objects.
Returns a Response PDU with the results of the request.
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# File 'lib/snmp/manager.rb', line 202 def get(object_list) varbind_list = @mib.varbind_list(object_list, :NullValue) request = GetRequest.new(@@request_id.next, varbind_list) try_request(request) end |
#get_bulk(non_repeaters, max_repetitions, object_list) ⇒ Object
Sends a get-bulk request. The non_repeaters parameter specifies the number of objects in the object_list to be retrieved once. The remaining objects in the list will be retrieved up to the number of times specified by max_repetitions.
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# File 'lib/snmp/manager.rb', line 248 def get_bulk(non_repeaters, max_repetitions, object_list) varbind_list = @mib.varbind_list(object_list, :NullValue) request = GetBulkRequest.new( @@request_id.next, varbind_list, non_repeaters, max_repetitions) try_request(request) end |
#get_next(object_list) ⇒ Object
Sends a get-next request for the supplied list of ObjectId or VarBind objects.
Returns a Response PDU with the results of the request.
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# File 'lib/snmp/manager.rb', line 236 def get_next(object_list) varbind_list = @mib.varbind_list(object_list, :NullValue) request = GetNextRequest.new(@@request_id.next, varbind_list) try_request(request) end |
#get_value(object_list) ⇒ Object
Sends a get request for the supplied list of ObjectId or VarBind objects.
Returns a list of the varbind values only, not the entire response, in the same order as the initial object_list. This method is useful for retrieving scalar values.
For example:
SNMP::Manager.open(:Host => "localhost") do |manager|
puts manager.get_value("sysDescr.0")
end
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# File 'lib/snmp/manager.rb', line 222 def get_value(object_list) if object_list.respond_to? :to_ary get(object_list).vb_list.collect { |vb| vb.value } else get(object_list).vb_list.first.value end end |
#inform(sys_up_time, trap_oid, object_list = []) ⇒ Object
Sends an inform request using the supplied varbind list.
sys_up_time: An integer respresenting the number of hundredths of a second that this system has been up.
trap_oid: An ObjectId or String with the OID identifier for this inform request.
object_list: A list of additional varbinds to send with the inform.
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# File 'lib/snmp/manager.rb', line 340 def inform(sys_up_time, trap_oid, object_list=[]) vb_list = create_trap_vb_list(sys_up_time, trap_oid, object_list) request = InformRequest.new(@@request_id.next, vb_list) try_request(request, @community, @host, @trap_port) end |
#load_module(name) ⇒ Object
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# File 'lib/snmp/manager.rb', line 192 def load_module(name) @mib.load_module(name) end |
#next_request_id=(request_id) ⇒ Object
Set the next request-id instead of letting it be generated automatically. This method is useful for testing and debugging.
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# File 'lib/snmp/manager.rb', line 444 def next_request_id=(request_id) @@request_id.force_next(request_id) end |
#set(object_list) ⇒ Object
Sends a set request using the supplied list of VarBind objects.
Returns a Response PDU with the results of the request.
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# File 'lib/snmp/manager.rb', line 263 def set(object_list) varbind_list = @mib.varbind_list(object_list, :KeepValue) request = SetRequest.new(@@request_id.next, varbind_list) try_request(request, @write_community) end |
#trap_v1(enterprise, agent_addr, generic_trap, specific_trap, timestamp, object_list = []) ⇒ Object
Sends an SNMPv1 style trap.
enterprise: The enterprise OID from the IANA assigned numbers (www.iana.org/assignments/enterprise-numbers) as a String or an ObjectId.
agent_addr: The IP address of the SNMP agent as a String or IpAddress.
generic_trap: The generic trap identifier. One of :coldStart, :warmStart, :linkDown, :linkUp, :authenticationFailure, :egpNeighborLoss, or :enterpriseSpecific
specific_trap: An integer representing the specific trap type for an enterprise-specific trap.
timestamp: An integer respresenting the number of hundredths of a second that this system has been up.
object_list: A list of additional varbinds to send with the trap.
For example:
Manager.open(:Version => :SNMPv1) do |snmp|
snmp.trap_v1(
"enterprises.9",
"10.1.2.3",
:enterpriseSpecific,
42,
12345,
[VarBind.new("1.3.6.1.2.3.4", Integer.new(1))])
end
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# File 'lib/snmp/manager.rb', line 302 def trap_v1(enterprise, agent_addr, generic_trap, specific_trap, , object_list=[]) vb_list = @mib.varbind_list(object_list, :KeepValue) ent_oid = @mib.oid(enterprise) agent_ip = IpAddress.new(agent_addr) specific_int = Integer(specific_trap) ticks = TimeTicks.new() trap = SNMPv1_Trap.new(ent_oid, agent_ip, generic_trap, specific_int, ticks, vb_list) send_request(trap, @community, @host, @trap_port) end |
#trap_v2(sys_up_time, trap_oid, object_list = []) ⇒ Object
Sends an SNMPv2c style trap.
sys_up_time: An integer respresenting the number of hundredths of a second that this system has been up.
trap_oid: An ObjectId or String with the OID identifier for this trap.
object_list: A list of additional varbinds to send with the trap.
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# File 'lib/snmp/manager.rb', line 323 def trap_v2(sys_up_time, trap_oid, object_list=[]) vb_list = create_trap_vb_list(sys_up_time, trap_oid, object_list) trap = SNMPv2_Trap.new(@@request_id.next, vb_list) send_request(trap, @community, @host, @trap_port) end |
#walk(object_list, index_column = 0) ⇒ Object
Walks a list of ObjectId or VarBind objects using get_next until the response to the first OID in the list reaches the end of its MIB subtree.
The varbinds from each get_next are yielded to the given block as they are retrieved. The result is yielded as a VarBind when walking a single object or as a VarBindList when walking a list of objects.
Normally this method is used for walking tables by providing an ObjectId for each column of the table.
For example:
SNMP::Manager.open(:Host => "localhost") do |manager|
manager.walk("ifTable") { |vb| puts vb }
end
SNMP::Manager.open(:Host => "localhost") do |manager|
manager.walk(["ifIndex", "ifDescr"]) do |index, descr|
puts "#{index.value} #{descr.value}"
end
end
The index_column identifies the column that will provide the index for each row. This information is used to deal with “holes” in a table (when a row is missing a varbind for one column). A missing varbind is replaced with a varbind with the value NoSuchInstance.
Note: If you are getting back rows where all columns have a value of NoSuchInstance then your index column is probably missing one of the rows. Choose an index column that includes all indexes for the table.
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# File 'lib/snmp/manager.rb', line 389 def walk(object_list, index_column=0) raise ArgumentError, "expected a block to be given" unless block_given? vb_list = @mib.varbind_list(object_list, :NullValue) raise ArgumentError, "index_column is past end of varbind list" if index_column >= vb_list.length is_single_vb = object_list.respond_to?(:to_str) || object_list.respond_to?(:to_varbind) start_list = vb_list start_oid = vb_list[index_column].name last_oid = start_oid loop do vb_list = get_next(vb_list).vb_list index_vb = vb_list[index_column] break if EndOfMibView == index_vb.value stop_oid = index_vb.name if stop_oid <= last_oid warn "OIDs are not increasing, #{last_oid} followed by #{stop_oid}" break end break unless stop_oid.subtree_of?(start_oid) last_oid = stop_oid if is_single_vb yield index_vb else vb_list = validate_row(vb_list, start_list, index_column) yield vb_list end end end |