Developing Your Own Flux Packages by David McKay | Head of Developer Relations | InfluxData

DevelopingYourOwn
FluxPackages
David McKay, DevRel at InﬂuxData

Agenda
★ A (Quick) Introduction to Flux
★ Standard Library
★ Writing Your Own Flux
★ What’s Coming Next?

5 © 2018 InﬂuxData. All rights reserved.
/ / This i s a comment
Com m ents

name =“ David McKay”
age = 1.2
a l i v e = t r u e
Assignment

name = “David McKay”
o b je c t s ={ name, age: 23}
Objects

t i m e L i t e r a l s = 2018-08-28T10:20:00Z
= 2018-08-28
dateMath = 2019- 01- 01 + 1mo3d
WorkingwithTime
d u r a t i o n L i t e r a l = 1mo7d

square = ( n ) => n * n
t w e e t ( a t : “rawkode”, message: “ S we e t ! ” )
Functions

UTF-8
> ʭ = ( ) => " I d o n ' t know what t h i s symbol i s c a l l e d "
> ʭ
( ) - > s t r i n g
> ʭ()
I d o n ' t know what t h i s symbol i s c a l l e d

UTF-8
> hotdog = ( ) => “Armour 🌭 ! ”
> hotdog()
> Armour 🌭 !
> 🌭 = ( ) => “Armour Hotdog!”
E r r o r: i n v a l i d statement @1: 1- 1: 5: 🌭

rawkode.ﬂux
package rawkode
gitHubHandle =
“rawkode” h e l l o
= ( ) => " H e l l o "
awesomeThings = [ "BBQ", " H o t Sauce", “ 🌭 ” ]

rawkode.ﬂux
package rawkode
awesomeise = ( t a b l e = < - ) => {
t a b l e |> map( fn : ( r ) => "Awesome" + r )
}

FluxREPL
rawkode@penguin:~ . / f l u x r e p l
> @rawkode.flux
> awesomeThings | > awesomeise

Limitations Your Flux packages will only be as good as our
standard library
Flux is still early

➔ CSV
➔ HTTP
➔ InﬂuxDB
➔ Kafka
➔ Math
➔ SQL
➔ Testing
➔ Will continue to grow …
StandardLibrary

Math
import "math"
math.NaN()
/ / Returns NaN

Math
import "math"
math. s q r t( x: 4.0 )
/ / Returns 2.0

Strings
import " s t r i n g s "
s t r i n g s . t i t l e ( v : " a f l u x o f f o x e s " )
/ / r e t u r n s "A Flux Of Foxes"

CSV
import " c s v "
c s v . f r o m ( f i l e : " / p a t h / t o / d a t a - f i l e . c s v " )
/ / OR
c s v . f r o m ( c s v : csvData)

Testing
import " t e s t i n g "
t e s t i n g . a s s e r t E q u a l s (
name: "some t e s t name",
g o t : g o t ,
want: want
)

https://v2.docs.inﬂuxdata.com/
Thank You,
Docs Team!
The v2 (InﬂuxDB) docs are a great way to
follow up on this:

★ Functional NB: It’s a functional language, by
design, as opposed to OOP.
I don’t mean “it kinda
works”
Our Vision is
Awesome
★ Flux is a generic data scripting language
★ It does/will support:
○ MySQL / PostgrSQL
○ Prometheus
○ Kafka
○ more!

Our Community
is Awesome
★ InﬂuxDB has 373 contributors
★ Telegraf has 520 contributors
★ Together they have over 20k+ stars

m ath.ﬂux
package math
/ / b u i l t i n constants
b u i l t i n p i
/ / b u i l t i n f unctions
b u i l t i n abs

math.go
package math
func i n i t ( ) {
/ / constants
f l u x . RegisterPackageValue( "math", " p i " ,
values.NewFloat(math.Pi))
}

Math has no rand()
What the
Flux!

NewFunction " g i t h u b . c o m / i n f l u x d a t a / f l u x / v a l u e s "

math.go
package math
func i n i t ( ) {
/ / constants
f l u x . RegisterPackageValue( "math", " p i " ,
values.NewFloat(math.Pi))
}

/ / rand f unction
math.go
package math
func i n i t ( ) {
/ / rand f u n c t i o n
flux.RegisterPackageValue (
values. NewFunction( “math”, ???)
)
}

values.NewFunction
★ Takes 4 parameters
○ Name of function
○ Function signature
○ Actual function + safety harness
○ Side eﬀect boolean

???
)
NewFunction:FunctionName
values. NewFunction(
" r a n d " ,
???,
???,

NewFunction:FunctionSignature
/ / rand wi t h no params
semantic.NewFunctionPolyType(semantic.FunctionPolySignature{
Parameters: map[string]semantic.PolyType{},
Return: semantic.UInt,
} ) ,
/ / i n Go: func r a n d ( ) u i n t

semantic.LabelSet{"max"},
semantic.UInt,
Required:
Return:
} ) ,
/ / in Go: f unc rand(max u i n t ) u i n t
/ / rand with 1 param: max
Parameters: map[string]semantic.PolyType{ "max":
semantic.Int
} ,

semantic.LabelSet{"min", "max"},
semantic.UInt,
Required:
Return:
} ) ,
/ / in Go: f unc rand(min u i n t , max u i n t ) u i n t
/ / rand with 2 param: min, max
Parameters: map[string]semantic.PolyType{ "min":
semantic.Int,
"max": semantic.Int
} ,

???
)
NewFunction:FunctionName&Signature
" r a n d " ,
semantic. NewFunctionPolyType( … )
???,

goRand : = rand.New(rand.NewSource(...))
NewFunction:Function(NoParams)
/ / 🌭 No Er r o r Checking 🌭
f u n c ( ) ( v a l u e s . V a l u e , e r r o r ) {
goRand : = rand.New(rand.NewSource(...))
r e t u r n values. NewUInt( goRand. I n t n ( 100) ) , n i l
}

NewFunction:Function(MaxParams)
f unc (args values . Objec t ) (values . V al ue , e r r o r ) {
max, ok : = args.Get("max")
i f ! o k {
r e t u r n n i l , errors.New("m issing argument max")
}
i f m ax.Type().Nature() == s e m a n t i c . I n t {
goRand : = rand.New(rand.NewSource(time.Now().UnixNano()))
r e t u r n values . NewUInt(goRand .Int n(max. Int())), n i l
}
r e t u r n n i l , f m t . E r r o r f (
"cannot convert argument o f type %vt o u i n t " ,
v . T y p e ( ) . N a t u r e ( )
)
}

???
)
NewFunction:FunctionName,Signature,&Function
" r a n d " ,
semantic.NewFunctionPolyType( … )
f unc( args values. Object) ( values. Value, e r r o r) { … } ,

NewFunction:SideEﬀect
Flux will optimise code that “appears” pointless
Using true for this parameter will ensure Flux runs such code
“Classical” side-eﬀects apply: network, disk, etc

NewFunction:🌟 Completed🌟
" r a n d " ,
semantic.NewFunctionPolyType( … )
f unc( args values. Object) ( values. Value, e r r o r) { … } ,
f a l s e
)

Compilation!==UnitTest

expected = 100
Test

Test
f l u x F n = v a lu e s . Ne wF u n c t i o n ( . . . )
f l u x A r g : = values.NewObjectWithValues(
m a p [ s t r in g ] v a lu e s . Va lu e {
"max": values.NewInt(expected)
}
)
r e s u l t , e r r : = f l u x F n . C a l l ( f l u x A r g )

What’sComingNext
Deﬁnitely Maybe

Extending Flux Shouldn’t Need Go
FluxinFlux

HTTP
Files
ENV
More
Flux
Our standard library should allow for you to write
Flux extensions without dropping down to Go:

e lse
o t h e r _ s t u f f
More
Flux
i f 1==1 then
s t u f f

More
Flux
{ r wit h _value : "Awesome", name:
"David McKay"}

You shouldn’t need to get your functionality
merged into inﬂuxdata/ﬂux
PackageManagement

This will be OSS
You’ll be able to run and secure your own
Flux
Public
Repo
We’ll provide a public repository for all Flux
packages

We’ve also seen Cargo and Mix
We’ll get this right
Flux
Public
Repo
Don’t worry, we’ve all seen what’s happened in
Go land

Documentation
You shouldn’t need to pause this video, browse
the standard library, or provide oﬀerings to a
deity to know how to do allthis

Docs 1. I want to add a source
2. I want to add a sink
3. I want to add a transformation
Scenario driven documentation:

Docs They’ve already done it*
*They’re on it
Our docs team areawesome

Developing Your Own Flux Packages by David McKay | Head of Developer Relations | InfluxData

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