pkgimporters

pkgimporters

A command-line tool to fetch the number of known importers for Go packages from pkg.go.dev.

Description

pkgimporters queries pkg.go.dev to retrieve importer counts for Go packages. It supports multiple ways to specify packages:

• Query specific packages via positional arguments
• Query packages using the -pkgs flag with comma-separated values (e.g., -pkgs fmt,bufio)
• Fetch all standard library packages with -pkgs std

Results can be sorted by package name (default) or by importer count in descending order.

Installation

go install github.com/alexandear/pkgimporters@latest

Usage

pkgimporters [-pkgs pkg1,pkg2,...|std] [-workers N] [-sort name|count] [package ...]

Options

• -pkgs - Comma-separated list of packages to fetch (e.g., -pkgs fmt,bufio) or 'std' for all standard library packages
• -workers N - Number of concurrent requests (default: 5)
• -sort - Sort results by 'name' (default) or 'count' (descending importer count)

Note: Flags must be specified before positional arguments.

Examples

Fetch importers for a single package:

❯ pkgimporters os
os                   2,397,740

Fetch importers for multiple packages:

❯ pkgimporters fmt bufio net/http golang.org/x/tools/go/analysis
bufio                          515,194
fmt                            5,485,422
golang.org/x/tools/go/analysis 6,136
net/http                       1,705,800

Use comma-separated list of packages:

❯ pkgimporters -pkgs io,math/rand/v2
io                   1,533,321
math/rand/v2         4,986

Fetch importers for all standard library packages (takes a while):

❯ pkgimporters std
archive/tar            27,061
archive/zip            22,244
bufio                  515,194
bytes                  1,204,809
cmp                    7,792
compress/bzip2         3,458
compress/flate         8,076
compress/gzip          77,599
compress/lzw           918
compress/zlib          12,336
container/heap         30,970
container/list         46,274
container/ring         4,077
context                1,967,772
crypto                 48,051
crypto/aes             43,798
crypto/cipher          49,170
crypto/des             6,441
crypto/dsa             5,046
crypto/ecdh            894
crypto/ecdsa           63,177
crypto/ed25519         8,319
crypto/elliptic        32,487
crypto/fips140         33
crypto/hkdf            47
crypto/hmac            54,631
crypto/hpke            0
crypto/md5             89,187
crypto/mlkem           57
crypto/mlkem/mlkemtest 0
crypto/pbkdf2          53
crypto/rand            199,629
crypto/rc4             4,819
crypto/rsa             55,943
crypto/sha1            78,079
crypto/sha256          133,589
crypto/sha3            122
crypto/sha512          31,041
crypto/subtle          23,649
crypto/tls             177,174
crypto/x509            115,983
crypto/x509/pkix       22,880
database/sql           192,619
database/sql/driver    33,356
debug/buildinfo        201
debug/dwarf            1,494
debug/elf              2,415
debug/gosym            417
debug/macho            903
debug/pe               951
debug/plan9obj         73
embed                  73,798
encoding               17,173
encoding/ascii85       537
encoding/asn1          17,469
encoding/base32        9,307
encoding/base64        231,634
encoding/binary        263,373
encoding/csv           43,453
encoding/gob           39,873
encoding/hex           236,380
encoding/json          1,456,575
encoding/pem           58,775
encoding/xml           75,937
errors                 1,580,116
expvar                 16,372
flag                   528,784
fmt                    5,485,422
go/ast                 39,682
go/build               19,289
go/build/constraint    163
go/constant            3,934
go/doc                 3,578
go/doc/comment         125
go/format              17,463
go/importer            2,172
go/parser              29,395
go/printer             7,151
go/scanner             4,376
go/token               41,812
go/types               15,525
go/version             77
hash                   67,614
hash/adler32           2,506
hash/crc32             21,411
hash/crc64             1,863
hash/fnv               21,297
hash/maphash           876
html                   15,318
html/template          116,219
image                  56,067
image/color            41,142
image/color/palette    1,083
image/draw             11,722
image/gif              9,201
image/jpeg             18,148
image/png              27,935
index/suffixarray      374
io                     1,533,321
io/fs                  41,598
io/ioutil              861,634
iter                   5,674
log                    1,359,920
log/slog               59,515
log/syslog             9,544
maps                   12,437
math                   589,822
math/big               221,940
math/bits              47,605
math/cmplx             3,712
math/rand              353,345
math/rand/v2           4,986
mime                   31,412
mime/multipart         45,161
mime/quotedprintable   1,289
net                    630,659
net/http               1,705,800
net/http/cgi           704
net/http/cookiejar     10,127
net/http/fcgi          1,107
net/http/httptest      17,540
net/http/httptrace     3,038
net/http/httputil      36,104
net/http/pprof         33,598
net/mail               25,070
net/netip              9,298
net/rpc                17,986
net/rpc/jsonrpc        2,254
net/smtp               12,041
net/textproto          17,188
net/url                557,415
os                     2,397,740
os/exec                256,170
os/signal              203,107
os/user                40,920
path                   296,255
path/filepath          663,112
plugin                 5,493
reflect                795,504
regexp                 487,451
regexp/syntax          1,410
runtime                405,611
runtime/cgo            1,004
runtime/coverage       27
runtime/debug          54,726
runtime/metrics        382
runtime/pprof          23,383
runtime/race           4
runtime/trace          3,493
slices                 59,822
sort                   551,464
strconv                1,435,979
strings                2,555,764
structs                123
sync                   1,296,984
sync/atomic            227,792
syscall                296,640
testing                107,228
testing/cryptotest     0
testing/fstest         193
testing/iotest         109
testing/quick          365
testing/slogtest       13
testing/synctest       3
text/scanner           4,090
text/tabwriter         31,186
text/template          110,065
text/template/parse    1,198
time                   2,721,686
time/tzdata            863
unicode                125,884
unicode/utf16          10,615
unicode/utf8           127,102
unique                 136
unsafe                 173,618
weak                   75

Sort by importer count (descending):

❯ time pkgimporters -pkgs std -sort count
fmt                    5,485,422
time                   2,721,686
strings                2,555,764
os                     2,397,740
context                1,967,772
net/http               1,705,800
errors                 1,580,116
io                     1,533,321
encoding/json          1,456,575
strconv                1,435,979
log                    1,359,920
sync                   1,296,984
bytes                  1,204,809
io/ioutil              861,634
reflect                795,504
path/filepath          663,112
net                    630,659
math                   589,822
net/url                557,415
sort                   551,464
flag                   528,784
bufio                  515,194
regexp                 487,451
runtime                405,611
math/rand              353,345
syscall                296,640
path                   296,255
encoding/binary        263,373
os/exec                256,170
encoding/hex           236,380
encoding/base64        231,634
sync/atomic            227,792
math/big               221,940
os/signal              203,107
crypto/rand            199,629
database/sql           192,619
crypto/tls             177,174
unsafe                 173,618
crypto/sha256          133,589
unicode/utf8           127,102
unicode                125,884
html/template          116,219
crypto/x509            115,983
text/template          110,065
testing                107,228
crypto/md5             89,187
crypto/sha1            78,079
compress/gzip          77,599
encoding/xml           75,937
embed                  73,798
hash                   67,614
crypto/ecdsa           63,177
slices                 59,822
log/slog               59,515
encoding/pem           58,775
image                  56,067
crypto/rsa             55,943
runtime/debug          54,726
crypto/hmac            54,631
crypto/cipher          49,170
crypto                 48,051
math/bits              47,605
container/list         46,274
mime/multipart         45,161
crypto/aes             43,798
encoding/csv           43,453
go/token               41,812
io/fs                  41,598
image/color            41,142
os/user                40,920
encoding/gob           39,873
go/ast                 39,682
net/http/httputil      36,104
net/http/pprof         33,598
database/sql/driver    33,356
crypto/elliptic        32,487
mime                   31,412
text/tabwriter         31,186
crypto/sha512          31,041
container/heap         30,970
go/parser              29,395
image/png              27,935
archive/tar            27,061
net/mail               25,070
crypto/subtle          23,649
runtime/pprof          23,383
crypto/x509/pkix       22,880
archive/zip            22,244
hash/crc32             21,411
hash/fnv               21,297
go/build               19,289
image/jpeg             18,148
net/rpc                17,986
net/http/httptest      17,540
encoding/asn1          17,469
go/format              17,463
net/textproto          17,188
encoding               17,173
expvar                 16,372
go/types               15,525
html                   15,318
maps                   12,437
compress/zlib          12,336
net/smtp               12,041
image/draw             11,722
unicode/utf16          10,615
net/http/cookiejar     10,127
log/syslog             9,544
encoding/base32        9,307
net/netip              9,298
image/gif              9,201
crypto/ed25519         8,319
compress/flate         8,076
cmp                    7,792
go/printer             7,151
crypto/des             6,441
iter                   5,674
plugin                 5,493
crypto/dsa             5,046
math/rand/v2           4,986
crypto/rc4             4,819
go/scanner             4,376
text/scanner           4,090
container/ring         4,077
go/constant            3,934
math/cmplx             3,712
go/doc                 3,578
runtime/trace          3,493
compress/bzip2         3,458
net/http/httptrace     3,038
hash/adler32           2,506
debug/elf              2,415
net/rpc/jsonrpc        2,254
go/importer            2,172
hash/crc64             1,863
debug/dwarf            1,494
regexp/syntax          1,410
mime/quotedprintable   1,289
text/template/parse    1,198
net/http/fcgi          1,107
image/color/palette    1,083
runtime/cgo            1,004
debug/pe               951
compress/lzw           918
debug/macho            903
crypto/ecdh            894
hash/maphash           876
time/tzdata            863
net/http/cgi           704
encoding/ascii85       537
debug/gosym            417
runtime/metrics        382
index/suffixarray      374
testing/quick          365
debug/buildinfo        201
testing/fstest         193
go/build/constraint    163
unique                 136
go/doc/comment         125
structs                123
crypto/sha3            122
testing/iotest         109
go/version             77
weak                   75
debug/plan9obj         73
crypto/mlkem           57
crypto/pbkdf2          53
crypto/hkdf            47
crypto/fips140         33
runtime/coverage       27
testing/slogtest       13
runtime/race           4
testing/synctest       3
crypto/hpke            0
crypto/mlkem/mlkemtest 0
testing/cryptotest     0
pkgimporters -pkgs std -sort count  0.74s user 1.44s system 1% cpu 2:53.79 total

Sort multiple packages by importer count:

❯ pkgimporters -sort count bufio fmt
fmt                  5,485,422
bufio                515,194

Use 20 concurrent requests:

pkgimporters -workers 20 -pkgs std