semver is a Semantic Versioning library written in golang. It fully covers spec version 2.0.0.

$ go get github.com/blang/semver

Note: Always vendor your dependencies or fix on a specific version tag.

import github.com/blang/semver
v1, err := semver.Make("1.0.0-beta")
v2, err := semver.Make("2.0.0-beta")
v1.Compare(v2)

Also check the GoDocs.

• Fully spec compatible
• No reflection
• No regex
• Fully tested (Coverage >99%)
• Readable parsing/validation errors
• Fast (See Benchmarks)
• Only Stdlib
• Uses values instead of pointers
• Many features, see below

• Parsing and validation at all levels
• Comparator-like comparisons
• Compare Helper Methods
• InPlace manipulation
• Ranges >=1.0.0 <2.0.0 || >=3.0.0 !3.0.1-beta.1
• Wildcards >=1.x, <=2.5.x
• Sortable (implements sort.Interface)
• database/sql compatible (sql.Scanner/Valuer)
• encoding/json compatible (json.Marshaler/Unmarshaler)

A Range is a set of conditions which specify which versions satisfy the range.

A condition is composed of an operator and a version. The supported operators are:

• <1.0.0 Less than 1.0.0
• <=1.0.0 Less than or equal to 1.0.0
• >1.0.0 Greater than 1.0.0
• >=1.0.0 Greater than or equal to 1.0.0
• 1.0.0, =1.0.0, ==1.0.0 Equal to 1.0.0
• !1.0.0, !=1.0.0 Not equal to 1.0.0. Excludes version 1.0.0.

Note that spaces between the operator and the version will be gracefully tolerated.

A Range can link multiple Ranges separated by space:

Ranges can be linked by logical AND:

• >1.0.0 <2.0.0 would match between both ranges, so 1.1.1 and 1.8.7 but not 1.0.0 or 2.0.0
• >1.0.0 <3.0.0 !2.0.3-beta.2 would match every version between 1.0.0 and 3.0.0 except 2.0.3-beta.2

Ranges can also be linked by logical OR:

• <2.0.0 || >=3.0.0 would match 1.x.x and 3.x.x but not 2.x.x

AND has a higher precedence than OR. It's not possible to use brackets.

Ranges can be combined by both AND and OR

• >1.0.0 <2.0.0 || >3.0.0 !4.2.1 would match 1.2.3, 1.9.9, 3.1.1, but not 4.2.1, 2.1.1

Range usage:

v, err := semver.Parse("1.2.3")
range, err := semver.ParseRange(">1.0.0 <2.0.0 || >=3.0.0")
if range(v) {
    //valid
}

Have a look at full examples in examples/main.go

import github.com/blang/semver

v, err := semver.Make("0.0.1-alpha.preview+123.github")
fmt.Printf("Major: %d\n", v.Major)
fmt.Printf("Minor: %d\n", v.Minor)
fmt.Printf("Patch: %d\n", v.Patch)
fmt.Printf("Pre: %s\n", v.Pre)
fmt.Printf("Build: %s\n", v.Build)

// Prerelease versions array
if len(v.Pre) > 0 {
    fmt.Println("Prerelease versions:")
    for i, pre := range v.Pre {
        fmt.Printf("%d: %q\n", i, pre)
    }
}

// Build meta data array
if len(v.Build) > 0 {
    fmt.Println("Build meta data:")
    for i, build := range v.Build {
        fmt.Printf("%d: %q\n", i, build)
    }
}

v001, err := semver.Make("0.0.1")
// Compare using helpers: v.GT(v2), v.LT, v.GTE, v.LTE
v001.GT(v) == true
v.LT(v001) == true
v.GTE(v) == true
v.LTE(v) == true

// Or use v.Compare(v2) for comparisons (-1, 0, 1):
v001.Compare(v) == 1
v.Compare(v001) == -1
v.Compare(v) == 0

// Manipulate Version in place:
v.Pre[0], err = semver.NewPRVersion("beta")
if err != nil {
    fmt.Printf("Error parsing pre release version: %q", err)
}

fmt.Println("\nValidate versions:")
v.Build[0] = "?"

err = v.Validate()
if err != nil {
    fmt.Printf("Validation failed: %s\n", err)
}

BenchmarkParseSimple-4           5000000    390    ns/op    48 B/op   1 allocs/op
BenchmarkParseComplex-4          1000000   1813    ns/op   256 B/op   7 allocs/op
BenchmarkParseAverage-4          1000000   1171    ns/op   163 B/op   4 allocs/op
BenchmarkStringSimple-4         20000000    119    ns/op    16 B/op   1 allocs/op
BenchmarkStringLarger-4         10000000    206    ns/op    32 B/op   2 allocs/op
BenchmarkStringComplex-4         5000000    324    ns/op    80 B/op   3 allocs/op
BenchmarkStringAverage-4         5000000    273    ns/op    53 B/op   2 allocs/op
BenchmarkValidateSimple-4      200000000      9.33 ns/op     0 B/op   0 allocs/op
BenchmarkValidateComplex-4       3000000    469    ns/op     0 B/op   0 allocs/op
BenchmarkValidateAverage-4       5000000    256    ns/op     0 B/op   0 allocs/op
BenchmarkCompareSimple-4       100000000     11.8  ns/op     0 B/op   0 allocs/op
BenchmarkCompareComplex-4       50000000     30.8  ns/op     0 B/op   0 allocs/op
BenchmarkCompareAverage-4       30000000     41.5  ns/op     0 B/op   0 allocs/op
BenchmarkSort-4                  3000000    419    ns/op   256 B/op   2 allocs/op
BenchmarkRangeParseSimple-4      2000000    850    ns/op   192 B/op   5 allocs/op
BenchmarkRangeParseAverage-4     1000000   1677    ns/op   400 B/op  10 allocs/op
BenchmarkRangeParseComplex-4      300000   5214    ns/op  1440 B/op  30 allocs/op
BenchmarkRangeMatchSimple-4     50000000     25.6  ns/op     0 B/op   0 allocs/op
BenchmarkRangeMatchAverage-4    30000000     56.4  ns/op     0 B/op   0 allocs/op
BenchmarkRangeMatchComplex-4    10000000    153    ns/op     0 B/op   0 allocs/op

See benchmark cases at semver_test.go

I simply couldn't find any lib supporting the full spec. Others were just wrong or used reflection and regex which i don't like.

Feel free to make a pull request. For bigger changes create a issue first to discuss about it.

See LICENSE file.