go2nix is best suited for Go apps written before dep or modules were introduced.
- If you see a
Gopkgs.lock
file in the source try dep2nix instead. - If you see a
go.mod
file in the source try vgo2nix or gomod2nix instead.
go2nix
provides an autmatic way to create Nix derivations for Go applications.
- Start with app sources that can be built on your machine with
go build
. It means that you need to get all dependencies into currentGOPATH
. - Run
go2nix save
in application source dir wheremain
package lives. This will create 2 filesdefault.nix
anddeps.nix
that can be moved into its own directory undernixpkgs
.
If you are not sure how to organize your directory structure, read this official guide first.
Our project will be called influxdb-demo
and this demo will be using the influxdb client library.
-
But first, prepare the project directory:
mkdir example cd example mkdir bin pkg src
-
Change into a
shell
environment which contains GO and GIT:nix-shell -p go git go2nix
Note: Make sure
go2nix
is at least version 1.1.1 -
Then set the
GOPATH
:export GOPATH=`pwd` mkdir -p src/github.com/qknight/influxdb-demo
-
Prepare
src/github.com/qknight/influxdb-demo/influxdb-client.go
:package main import ( "log" "time" "github.com/influxdata/influxdb/client/v2" ) const ( MyDB = "square_holes" username = "bubba" password = "bumblebeetuna" ) func main() { // Make client c, err := client.NewHTTPClient(client.HTTPConfig{ Addr: "http://localhost:8086", Username: username, Password: password, }) if err != nil { log.Fatalln("Error: ", err) } // Create a new point batch bp, err := client.NewBatchPoints(client.BatchPointsConfig{ Database: MyDB, Precision: "s", }) if err != nil { log.Fatalln("Error: ", err) } // Create a point and add to batch tags := map[string]string{"cpu": "cpu-total"} fields := map[string]interface{}{ "idle": 10.1, "system": 53.3, "user": 46.6, } pt, err := client.NewPoint("cpu_usage", tags, fields, time.Now()) if err != nil { log.Fatalln("Error: ", err) } bp.AddPoint(pt) // Write the batch c.Write(bp) }
Note: We use go influxdb client as an external library example.
-
Create a
GIT
repositorycd src/github.com/qknight/influxdb-demo git init git add influxdb-client.go git commit -m 'initial commit'
Also create the repository on github.com, in this example it would be
github.com/qknight/influxdb-demo
git remote add origin [email protected]:qknight/influxdb-demo.git git push -u origin master
Note:
go2nix
requires aGIT repository
to retrieve thecommit hash
and theremote
so it can generate the values asname
,version
,rev
andgoPackagePath
in thedefault.nix
file. -
Download the dependency the go-way
go get
Note:
go get
will populatesrc/github.com/influxdata/influxdb
for you. -
Building the project
go build
-
Generate
default.nix
/deps.nix
If
go
was able to build the binary, usego2nix
to derive thedefault.nix
anddeps.nix
:go2nix save
Note: This gives you a
default.nix
and adeps.nix
which can be put intonixpkgs
but, if you want to use it withnix-shell
, you need some tiny adaptions. -
The
default.nix
file we generated# This file was generated by go2nix. { stdenv, buildGoPackage, fetchgit, fetchhg, fetchbzr, fetchsvn }: buildGoPackage rec { name = "influxdb-demo-${version}"; version = "20161030-${stdenv.lib.strings.substring 0 7 rev}"; rev = "718c85cd733bca964abf03f5371c939d19845f72"; goPackagePath = "github.com/qknight/influxdb-demo"; src = fetchgit { inherit rev; url = "[email protected]:qknight/influxdb-demo.git"; sha256 = "0csbqcnncklimysgcbxlj190bynx1ppvyxvl5viz40fvbcj4l8xb"; }; goDeps = ./deps.nix; # TODO: add metadata https://nixos.org/nixpkgs/manual/#sec-standard-meta-attributes meta = { }; }
Note: Update the
fetchgit url
to usehttps
instead ofssh
ornix-build
won't be able to fetch the software later.Note: If you want to use this
default.nix
innixpkgs
you should extend the meta section and correct thegoPackagePath
. -
The
deps.nix
we generated# This file was generated by go2nix. [ { goPackagePath = "github.com/influxdata/influxdb"; fetch = { type = "git"; url = "https://github.com/influxdata/influxdb"; rev = "bcb48a8ff2e9c118d5cfa04f03a62134b9c414c7"; sha256 = "1f4jp7p2xxlsxhqbvglcl95y7fhab0w6zsvyqmqglmi0g1c5v21z"; }; } ]
-
Building the project using
nix-build
nix-build -E 'with import <nixpkgs> { }; callPackage ./default.nix {}'
This will print something like this:
these derivations will be built: /nix/store/8naxqswyhsmhqhjzskz5q0nf33nvyzsf-influxdb-demo-718c85c.drv /nix/store/p9bgjqn683xkmns36fpw2ipz5k57srl3-influxdb-bcb48a8.drv /nix/store/k0q9k2wfq0ccdsy04pyg4l01iqh5j1aa-go1.7-influxdb-demo-20161030-718c85c.drv building path(s) ‘/nix/store/45jjx5jakvlgwzq358pivr5x8xpgdsck-influxdb-bcb48a8’ building path(s) ‘/nix/store/pqlqq2wjgixvf5j6qmrv5qyjh1bc6i8q-influxdb-demo-718c85c’ exporting https://github.com/influxdata/influxdb (rev bcb48a8ff2e9c118d5cfa04f03a62134b9c414c7) into /nix/store/45jjx5jakvlgwzq358pivr5x8xpgdsck-influxdb-bcb48a8 exporting https://github.com/qknight/influxdb-demo.git (rev 718c85cd733bca964abf03f5371c939d19845f72) into /nix/store/pqlqq2wjgixvf5j6qmrv5qyjh1bc6i8q-influxdb-demo-718c85c Initialized empty Git repository in /nix/store/45jjx5jakvlgwzq358pivr5x8xpgdsck-influxdb-bcb48a8/.git/ Initialized empty Git repository in /nix/store/pqlqq2wjgixvf5j6qmrv5qyjh1bc6i8q-influxdb-demo-718c85c/.git/ remote: Counting objects: 3, done. remote: Compressing objects: 100% (2/2), done. remote: Total 3 (delta 0), reused 3 (delta 0), pack-reused 0 From https://github.com/qknight/influxdb-demo * branch HEAD -> FETCH_HEAD Switched to a new branch 'fetchgit' removing `.git'... remote: Counting objects: 540, done. remote: Compressing objects: 100% (506/506), done. remote: Total 540 (delta 34), reused 179 (delta 6), pack-reused 0 Receiving objects: 100% (540/540), 1.44 MiB | 0 bytes/s, done. Resolving deltas: 100% (34/34), done. From https://github.com/influxdata/influxdb * branch HEAD -> FETCH_HEAD Switched to a new branch 'fetchgit' removing `.git'... building path(s) ‘/nix/store/9k4v7rhs5606fyia8mb341k71m3yrcbq-go1.7-influxdb-demo-20161030-718c85c-bin’, ‘/nix/store/av17zlfgnppl704wwxnh5pjpkcxac9k3-go1.7-influxdb-demo-20161030-718c85c’ unpacking sources unpacking source archive /nix/store/pqlqq2wjgixvf5j6qmrv5qyjh1bc6i8q-influxdb-demo-718c85c source root is influxdb-demo-718c85c patching sources configuring grep: Invalid range end unpacking source archive /nix/store/45jjx5jakvlgwzq358pivr5x8xpgdsck-influxdb-bcb48a8 building github.com/influxdata/influxdb/pkg/escape github.com/influxdata/influxdb/models github.com/influxdata/influxdb/client/v2 github.com/qknight/influxdb-demo installing /tmp/nix-build-go1.7-influxdb-demo-20161030-718c85c.drv-0/go /tmp/nix-build-go1.7-influxdb-demo-20161030-718c85c.drv-0 /tmp/nix-build-go1.7-influxdb-demo-20161030-718c85c.drv-0 post-installation fixup shrinking RPATHs of ELF executables and libraries in /nix/store/9k4v7rhs5606fyia8mb341k71m3yrcbq-go1.7-influxdb-demo-20161030-718c85c-bin shrinking /nix/store/9k4v7rhs5606fyia8mb341k71m3yrcbq-go1.7-influxdb-demo-20161030-718c85c-bin/bin/influxdb-demo stripping (with flags -S) in /nix/store/9k4v7rhs5606fyia8mb341k71m3yrcbq-go1.7-influxdb-demo-20161030-718c85c-bin/bin patching script interpreter paths in /nix/store/9k4v7rhs5606fyia8mb341k71m3yrcbq-go1.7-influxdb-demo-20161030-718c85c-bin shrinking RPATHs of ELF executables and libraries in /nix/store/av17zlfgnppl704wwxnh5pjpkcxac9k3-go1.7-influxdb-demo-20161030-718c85c patching script interpreter paths in /nix/store/av17zlfgnppl704wwxnh5pjpkcxac9k3-go1.7-influxdb-demo-20161030-718c85c /nix/store/9k4v7rhs5606fyia8mb341k71m3yrcbq-go1.7-influxdb-demo-20161030-718c85c-bin
Note: The resulting binary will be in
/nix/store/9k4v7rhs5606fyia8mb341k71m3yrcbq-go1.7-influxdb-demo-20161030-718c85c-bin
. -
Enabling
nix-shell
In order to use
nix-shell
you need to create ashell.nix
file:let pkgs = import <nixpkgs> {}; in pkgs.callPackage ./default.nix {}
That will pass the derivations for
stdenv, buildGoPackage, fetchgit, fetchhg, fetchbzr, fetchsvn
into your package derivation. It will usenixpkgs
(your current channel).After you updated the
default.nix
you can now usenix-shell
:nix-shell these paths will be fetched (47.89 MiB download, 248.86 MiB unpacked): /nix/store/28wl3f34vfjpw0y5809bgr6382wqdscf-bash-4.3-p48 /nix/store/7bdn99q835l042d8kcrn7yk61zkcqw6y-go1.7-govers-20150109-3b5f175 /nix/store/aql31436x2fgr3rdj4fwbrgkvzw2kqf4-iana-etc-2.30 /nix/store/bb2njjq32bh1wl2nl1zss0i8w1w2jgrz-tzdata-2016f /nix/store/dp2nf60lqzy1kbhd78ndf5nm3fb3qicd-gcc-wrapper-5.4.0 /nix/store/drfmgb3kd3clxzi919mjrq5cnkw575w0-stdenv /nix/store/fkzyjrmrxv1zgswdq327h11ifbxdfpf9-go1.7-govers-20150109-3b5f175-bin /nix/store/g1pacy3pmx9r846z87xysfs29jz2b42q-parallel-20160722 /nix/store/g4f1bms36hgg5abfd8xc4bj6sfzsy61d-bash-4.3-p48-info /nix/store/i76bwv541a7zj576hkdia62169r2nl0z-bash-4.3-p48-doc /nix/store/jqa9bh404crcxnyxa2lkffag7kw3yxw3-go-1.7.1 /nix/store/jx5fyfd6mkpib1dmgy5rjirxff5vaczm-procps-3.3.11 /nix/store/kx62kzlxcmzxgnxz1c95x7gln72iqd90-ncurses-6.0 /nix/store/njn6il2fwaycjkd0jxbfj22gb25nd5df-perl-5.22.2 fetching path ‘/nix/store/i76bwv541a7zj576hkdia62169r2nl0z-bash-4.3-p48-doc’... fetching path ‘/nix/store/g4f1bms36hgg5abfd8xc4bj6sfzsy61d-bash-4.3-p48-info’... fetching path ‘/nix/store/aql31436x2fgr3rdj4fwbrgkvzw2kqf4-iana-etc-2.30’... fetching path ‘/nix/store/bb2njjq32bh1wl2nl1zss0i8w1w2jgrz-tzdata-2016f’... ...
After the dependencies were built you can now use:
go build
to build your software as usual!Note: You can also arrange a
default.nix
so that it can be used bynixpkgs
andnix-shell
but this is not covered here.
Some projects are built using go get github.com/jeffail/leaps/cmd/...
and for these you need to identify the src
directory to run go2nix save
from. So here is another example:
nix-shell -p go2nix git go
cd $(mktemp -d)
export GOPATH=$(pwd)
go get github.com/jeffail/leaps/cmd/...
cd src/github.com/jeffail/leaps/cmd/leaps
go2nix save
Note: The resulting default.nix
and deps.nix
are created in the directory you are currently in.
The preferred way of installing go2nix
is to use nix
like nix-env -iA go2nix
or using it declaratively.
But you can also use go get github.com/kamilchm/go2nix
.