build: investigate shrinking WASM blob size using tiny-go

[Roasbeef]

Was brought up in this twitter thread: https://twitter.com/roasbeef/status/1486422025816064000

TinyGo is an alternate Go compiler that is intended for embedded systems, and support compiling to a WASM target: https://tinygo.org/docs/reference/usage/subcommands/#build.

Their overview page demonstrators shrinking a binary size by 99% just by instead compiling using the Tiny Go compiler. Certain Go language features aren't fully supported, so we may need to add some additional build tag layers to make it possible. So far, someone has identified that we'll need to build tag out the pprof import at the very least.

[kaloudis]

runtime/trace package is incompatible. This breaks all the OpenTelemetry stuff
tinygo-org/tinygo#1997

[kaloudis]

stdlib compatibility list here: https://tinygo.org/docs/reference/lang-support/stdlib/

I've assessed all the dependencies in LNC directly, and pulled in through vendor

issues with imports:

archive/tar
crypto/ed25519
crypto/tls
crypto/x509
encoding/xml
expvar
net/http
net/http/httptest
net/http/httptrace
net/http/httputil
net/http/pprof
os/user

issues with tests:

bufio
bytes
compress/gzip
context
crypto
crypto/aes
crypto/cipher
crypto/ecdsa
crypto/elliptic
crypto/hmac
crypto/rsa
crypto/subtle
database/sql
database/sql/driver
encoding/asn1
encoding/base64
encoding/binary
encoding/json
encoding/pem
errors
flag
fmt
go/token
hash/crc32
html/template
image/color
io
io/ioutil
log
log/syslog
math/big
math/bits
math/rand
mime
net/textproto
net/url
os/exec
os/signal
path/filepath
regexp
sort
strconv
strings
sync/atomic
syscall
text/tabwriter

[Roasbeef]

Re OpenTelemetry, looks like it's just a dep brought in thru aperture:

⛰   go mod why go.opentelemetry.io/contrib
# go.opentelemetry.io/contrib
github.com/lightninglabs/lightning-node-connect/itest
github.com/lightninglabs/aperture
github.com/lightninglabs/aperture.test
go.etcd.io/etcd/server/v3/embed
go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc
go.opentelemetry.io/contrib

In this case, it's only really required atm for the itests, so there might just need to add a build tag workaround.

[Roasbeef]

Not being able to import net/http seems like a pretty fundamental barrier.

However, I wonder if it's possible for us to take a multi-pronged approach here. With this hypothetical path, we'd actually have multiple wasm files, with us trying to pack as much into the tinygo compiled file as possible. I'm not sure if this is actually possible based on the way the project is architected however.

[Roasbeef]

In terms of shrinking things after the fact, looks like we might be able to use this wasm-opt tool to strip things down a bit more (namely the debug information): https://github.com/WebAssembly/binaryen#binaryen-optimizations.

Here's a blog post that shows an example near the end: https://www.fermyon.com/blog/optimizing-tinygo-wasm#Reducing%20More%20with%20Wasm-opt

[Roasbeef]

I tried gzip'ing locally, and got a pretty nice size reduction:

-rwxr-xr-x  1 roasbeef  staff    42M Jul 14 15:32 wasm-client.wasm
-rwxr-xr-x  1 roasbeef  staff   8.9M Jul 14 15:32 wasm-client.wasm.gz

[secondl1ght]

Are there any updates on this? I think it would be great to make more optimizations for file size, the current WASM file is sitting at 57.1mb. I was able to get it down to 49.6mb using wasm-opt which is an improvement but still not great.