GCI, a tool that controls Go package import order and makes it always deterministic.
The desired output format is highly configurable and allows for more custom formatting than goimport does.
GCI considers a import block based on AST as below:
Doc
Name Path Comment
All comments will keep as they were, except the isolated comment blocks.
The isolated comment blocks like below:
import (
"fmt"
// this line is isolated comment
// those lines belong to one
// isolated comment blocks
"github.com/daixiang0/gci"
)
GCI splits all import blocks into different sections, now support six section type:
- standard: Go official imports, like "fmt"
- custom: Custom section, use full and the longest match (match full string first, if multiple matches, use the longest one)
- default: All rest import blocks
- blank: Put blank imports together in a separate group
- dot: Put dot imports together in a separate group
- alias: Put alias imports together in a separate group
- localmodule: Put imports from local packages in a separate group
The priority is standard > default > custom > blank > dot > alias > localmodule, all sections sort alphabetically inside. By default, blank, dot, and alias sections are not used, and the corresponding lines end up in the other groups.
All import blocks use one TAB(\t) as Indent.
Since v0.9.0, GCI always puts C import block as the first.
Note:
nolint is hard to handle at section level, GCI will consider it as a single comment.
Local module detection is done via reading the module name from the go.mod
file in the directory where gci is invoked. This means:
- This mode works when
gciis invoked from a module root (i.e. directory containinggo.mod) - This mode doesn't work with a multi-module setup, i.e. when
gciis invoked from a directory containinggo.work(though it would work if invoked from within one of the modules in the workspace)
To download and install the highest available release version -
go install github.com/daixiang0/gci@latestYou may also specify a specific version, for example:
go install github.com/daixiang0/[email protected]Now GCI provides two command line methods, mainly for backward compatibility.
GCI supports three modes of operation
Note
Since v0.10.0, the
-sand--sectionflag can only be used multiple times to specify multiple sections. For example, you could use-s standard,defaultbefore, but now you must use-s standard -s default. This breaking change makes it possible for the project to support specifying multiple custom prefixes. (Please see below.)
$ gci print -h
Print outputs the formatted file. If you want to apply the changes to a file use write instead!
Usage:
gci print path... [flags]
Aliases:
print, output
Flags:
--custom-order Enable custom order of sections
-d, --debug Enables debug output from the formatter
-h, --help help for print
-s, --section stringArray Sections define how inputs will be processed. Section names are case-insensitive and may contain parameters in (). The section order is standard > default > custom > blank > dot > alias > localmodule. The default value is [standard,default].
standard - standard section that Go provides officially, like "fmt"
Prefix(github.com/daixiang0) - custom section, groups all imports with the specified Prefix. Imports will be matched to the longest Prefix. Multiple custom prefixes may be provided, they will be rendered as distinct sections separated by newline. You can regroup multiple prefixes by separating them with comma: Prefix(github.com/daixiang0,gitlab.com/daixiang0,daixiang0)
default - default section, contains all rest imports
blank - blank section, contains all blank imports.
dot - dot section, contains all dot imports. (default [standard,default])
alias - alias section, contains all alias imports.
localmodule: localmodule section, contains all imports from local packages
--skip-generated Skip generated files
--skip-vendor Skip files inside vendor directory$ gci write -h
Write modifies the specified files in-place
Usage:
gci write path... [flags]
Aliases:
write, overwrite
Flags:
--custom-order Enable custom order of sections
-d, --debug Enables debug output from the formatter
-h, --help help for write
-s, --section stringArray Sections define how inputs will be processed. Section names are case-insensitive and may contain parameters in (). The section order is standard > default > custom > blank > dot > alias > localmodule. The default value is [standard,default].
standard - standard section that Go provides officially, like "fmt"
Prefix(github.com/daixiang0) - custom section, groups all imports with the specified Prefix. Imports will be matched to the longest Prefix. Multiple custom prefixes may be provided, they will be rendered as distinct sections separated by newline. You can regroup multiple prefixes by separating them with comma: Prefix(github.com/daixiang0,gitlab.com/daixiang0,daixiang0)
default - default section, contains all rest imports
blank - blank section, contains all blank imports.
dot - dot section, contains all dot imports. (default [standard,default])
alias - alias section, contains all alias imports.
localmodule: localmodule section, contains all imports from local packages
--skip-generated Skip generated files
--skip-vendor Skip files inside vendor directory$ gci list -h
Prints the filenames that need to be formatted. If you want to show the diff use diff instead, and if you want to apply the changes use write instead
Usage:
gci list path... [flags]
Flags:
--custom-order Enable custom order of sections
-d, --debug Enables debug output from the formatter
-h, --help help for list
-s, --section stringArray Sections define how inputs will be processed. Section names are case-insensitive and may contain parameters in (). The section order is standard > default > custom > blank > dot > alias > localmodule. The default value is [standard,default].
standard - standard section that Go provides officially, like "fmt"
Prefix(github.com/daixiang0) - custom section, groups all imports with the specified Prefix. Imports will be matched to the longest Prefix. Multiple custom prefixes may be provided, they will be rendered as distinct sections separated by newline. You can regroup multiple prefixes by separating them with comma: Prefix(github.com/daixiang0,gitlab.com/daixiang0,daixiang0)
default - default section, contains all rest imports
blank - blank section, contains all blank imports.
dot - dot section, contains all dot imports. (default [standard,default])
alias - alias section, contains all alias imports.
localmodule: localmodule section, contains all imports from local packages
--skip-generated Skip generated files
--skip-vendor Skip files inside vendor directory$ gci diff -h
Diff prints a patch in the style of the diff tool that contains the required changes to the file to make it adhere to the specified formatting.
Usage:
gci diff path... [flags]
Flags:
--custom-order Enable custom order of sections
-d, --debug Enables debug output from the formatter
-h, --help help for diff
-s, --section stringArray Sections define how inputs will be processed. Section names are case-insensitive and may contain parameters in (). The section order is standard > default > custom > blank > dot > alias > localmodule. The default value is [standard,default].
standard - standard section that Go provides officially, like "fmt"
Prefix(github.com/daixiang0) - custom section, groups all imports with the specified Prefix. Imports will be matched to the longest Prefix. Multiple custom prefixes may be provided, they will be rendered as distinct sections separated by newline. You can regroup multiple prefixes by separating them with comma: Prefix(github.com/daixiang0,gitlab.com/daixiang0,daixiang0)
default - default section, contains all rest imports
blank - blank section, contains all blank imports.
dot - dot section, contains all dot imports. (default [standard,default])
alias - alias section, contains all alias imports.
localmodule: localmodule section, contains all imports from local packages
--skip-generated Skip generated files
--skip-vendor Skip files inside vendor directoryGci enables automatic formatting of imports in a deterministic manner
If you want to integrate this as part of your CI take a look at golangci-lint.
Usage:
gci [-diff | -write] [--local localPackageURLs] path... [flags]
gci [command]
Available Commands:
completion Generate the autocompletion script for the specified shell
diff Prints a git style diff to STDOUT
help Help about any command
list Prints filenames that need to be formatted to STDOUT
print Outputs the formatted file to STDOUT
write Formats the specified files in-place
Flags:
-d, --diff display diffs instead of rewriting files
-h, --help help for gci
-l, --local strings put imports beginning with this string after 3rd-party packages, separate imports by comma
-v, --version version for gci
-w, --write write result to (source) file instead of stdout
Use "gci [command] --help" for more information about a command.Note::
The old style is only for local tests, will be deprecated, please uses new style, golangci-lint uses new style as well.
Run gci write -s standard -s default -s "prefix(github.com/daixiang0/gci)" main.go and you will handle following cases:
package main
import (
"golang.org/x/tools"
"fmt"
"github.com/daixiang0/gci"
)to
package main
import (
"fmt"
"golang.org/x/tools"
"github.com/daixiang0/gci"
)package main
import (
"fmt"
go "github.com/golang"
"github.com/daixiang0/gci"
)to
package main
import (
"fmt"
go "github.com/golang"
"github.com/daixiang0/gci"
)package main
import (
"fmt"
go "github.com/golang"
_ "github.com/golang/blank"
. "github.com/golang/dot"
"github.com/daixiang0/gci"
_ "github.com/daixiang0/gci/blank"
. "github.com/daixiang0/gci/dot"
)to
package main
import (
"fmt"
go "github.com/golang"
"github.com/daixiang0/gci"
_ "github.com/daixiang0/gci/blank"
_ "github.com/golang/blank"
. "github.com/daixiang0/gci/dot"
. "github.com/golang/dot"
)package main
import (
testing "github.com/daixiang0/test"
"fmt"
g "github.com/golang"
"github.com/daixiang0/gci"
"github.com/daixiang0/gci/subtest"
)to
package main
import (
"fmt"
"github.com/daixiang0/gci"
"github.com/daixiang0/gci/subtest"
testing "github.com/daixiang0/test"
g "github.com/golang"
)Assuming this is run on the root of this repo (i.e. where
github.com/daixiang0/gci is a local module)
package main
import (
"os"
"github.com/daixiang0/gci/cmd/gci"
)to
package main
import (
"os"
"github.com/daixiang0/gci/cmd/gci"
)- Ensure only one blank between
NameandPathin an import block - Ensure only one blank between
PathandCommentin an import block - Format comments
- Add more testcases
- Support imports completion (please use
goimportsfirst then use GCI) - Optimize comments
- Remove Analyzer layer and fully use analyzer syntax