Idiomatic type-safe Scala DSL for SNMP
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README.rst

SNMP4S is an idiomatic type-safe Scala DSL for SNMP. This library begins with an SBT plugin which treats MIBs as source files. These MIBs are parsed and compiled into Scala objects. The compiled MIBs along with the base SNMP4S libraries form a powerful DSL for manipulating SNMP data.

Design Goals

  • Provide a powerful DSL that is a pleasure to use.
  • Reduce programmer mistakes by utilizing Scala's type system.
  • Generate code from the MIBs that define the SNMP interface to maximize the benefit of type safety.
  • Encapsulate all references to SNMP4J to allow changing out the underlying stack.
  • Provide multiple programming models for handling requests, responses, and errors (synchronous, asynchronous, excepting, etc)

Components

SNMP4S consists of three components

  1. snmp4s-core: The wrapper around SNMP4J that does the runtime work (licensed under APL 2.0.)
  2. snmp4s-gen: The code that utilizes Mibble to generate Scala code (licensed under GPL 3.0.)
  3. snmp4s-sbt: The SBT plugin that utilizes snmp4s-gen to compile MIBs (licesned under GPL 3.0.)

Installation

The latest release is 0.2.0. snmp4s-core is now built against 2.11, but snmp4s-gen and snmp4s-sbt are built against 2.10 and down for sbt.

First, you need to add snmp4s-sbt as an SBT Plugin in your project. Although SNMP4S is available from Maven Central, our dependency on Mibble will require a resolver in addition to the plugin declaration

resolvers += "Mibble" at "http://maven.cloudhopper.com/repos/third-party/"

addSbtPlugin("org.snmp4s" % "snmp4s-sbt" % "0.1.0")

Secondly, you need to add snmp4s-core as a dependency in your project build file. Again, we require an additional resolver but this time for our dependency on SNMP4J

resolvers += "OO SNMP" at "https://oosnmp.net/dist/release/"

libraryDependencies += "org.snmp4s" %% "snmp4s-core" % "0.2.0" // Use 0.1.0 if you are still using scala 2.10

Configuration

Any MIBs that are built in as part of SNMP4S can be declared in your project build file (see the org.snmp4s.gen.BuiltIn scaladocs/source for an exhaustive list of available MIBs)

import org.snmp4s.gen.BuiltIn._

snmp4sBuiltInMibs := Seq(IfMib, AdslLineMib)

Custom MIBs are simply placed in the src/main/mibs directory of your project. All files in the directory will be treated as a MIB regardless of filename

~/code/snmp4s/example/src/main/mibs $ ls -1
AGENTPP-GLOBAL-REG.txt
AGENTPP-SIMULATION-MIB.txt

Finally, you can specify the package prefix for all of the generated MIB objects, shown here with the default value:

snmp4sMibPackage := "org.snmp4s.mib"

Each MIB file will produce a Scala file in package <snmp4sMibPackage>.<CamelCasedMibName>. For instance, the IF-MIB with the default snmp4sMibPackage value will create the package org.snmp4s.mib.IfMib. A case class is generated for every leaf OID in the MIB. Also, enumeration classes are generated for OIDs with an enumerated integer syntax.

Code Examples That Work

This can be done today. See the example directory for a working project which utilizes SNMP4S

// Instantiate a new Snmp object, shown here with defaults for IP, port, community, etc.
val snmp = new Snmp(SnmpParams(
  ip = "127.0.0.1",
  port = 161,
  read = "public",
  write = "private",
  version = Version1,
  retries = 2,
  timeout = 1500
))

// Import some implicits
import Mib._

// Import the compiled MIB packages.  This package is settable via snmp4sMibPackage property
import org.snmp4s.mib._

// Import the compiled MIBs you want to work with
import IfMib._

// Get the value assigned to ifDescr.1
snmp.get(IfDescr(1)) match {
  case Left(err) => // Something bad happened
  case Right(v)  => // v is set to the ifDescr.1's value
}

// Get ifNumber.0. Since it is a scalar, we can drop the (0) index.
snmp.get(IfNumber) match {
  case Left(err) => // Something bad happened
  case Right(v)  => // v is set to the ifNumber's value
}

// Set ifAlias.1 to "My Interface"
snmp.set(IfAlias(1) to "My Interface") match {
  case Some(err) => // Something bad happened
  case _         => // It worked
}

// Walk ifDescr and return tuples containing the index and the value
snmp walk IfDescr match {
  case Left(err)   => Seq() // Something bad happened
  case Right(walk) => walk map { vb => (vb.obj.oid.last, vb.v) }
}

// OIDs with enumerated integer syntax are a cinch to work with
import IfAdminStatus_enum._
set(IfAdminStatus(1) to Down)
get(IfAdminStatus(1)) match {
  case Left(err) =>  // Something bad happened
  case Right(status) => status match {
    case Up      =>  // I'm up
    case Down    =>  // I'm down
    case Testing =>  // I'm testing
  }
}

// Can pattern match against the OIDs
val testPorts = snmp walk IfAdminStatus match {
  case Left(err)   => Seq() // Something bad happened
  case Right(walk) => for(VarBind(IfAdminStatus(Seq(i)), Testing) <- walk) yield i
}

Code Examples That Don't Work

As important as code that works, is code that doesn't. These mistakes will not compile

val snmp = new Snmp(SnmpParams())

// Cannot set a Read-only OID
snmp.set(IfDescr(1) to "description")
// inferred type arguments [org.snmp4s.ReadOnly,String] do not conform to method set's type
// parameter bounds [A <: org.snmp4s.Writable,T]
// [error]         snmp.set(IfDescr(1) to "description")
// [error]              ^

// Cannot set an OID with an Int syntax with a String
snmp.set(IfAdminStatus(1) to "2")
// type mismatch;
// [error]  found   : String("2")
// [error]  required: Int
// [error]           snmp.set(IfAdminStatus(1) to "2")
// [error]                                        ^

// Cannot get the wrong type
val descr:Either[String,Int] = snmp get IfDescr(1)
// type mismatch;
// [error]  found   : Either[String,String]
// [error]  required: Either[String,Int]
// [error]           val descr:Either[String,Int] = snmp get IfDescr(1)
// [error]                                               ^

Environment

Other than the usual need for git, sbt, and jdk, sbt will need root access to run the test suites for the snmp4s-core project. The integration tests use SNMP4J-Agent which needs to bind to port 161.

Contributions

Pull requests are welcomed.

License

snmp4s-core is licensed under APL 2.0.

Copyright 2013 org.snmp4s

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

snmp4s-gen and snmp4s-sbt are licensed under GPL 3.0.

While I prefer APL, snmp4s-gen and hence snmp4s-sbt utilize Mibble which is a GPL-licensed library. Fortunately for any use cases I have imagined, you will only use snmp4s-gen and snmp4s-sbt in development. Of the three projects, only snmp4s-core needs to be utilized by your running application.