node-linkerd-trace

``
.___ .__ .__ __ .___ __
____ ____ __| _/____ | | |__| ____ | | __ ___________ __| _/ _/ |_____________ ____ ____
/ \ / _ \ / __ |/ __ \ ______ | | | |/ \| |/ // __ \_ __ \/ __ | ______ \ __\_ __ \__ \ _/ ___\/ __ \
| | ( <_> ) /_/ \ ___/ /_____/ | |_| | | \ <\ ___/| | \/ /_/ | /_____/ | | | | \// __ \\ \__\ ___/
|___| /\____/\____ |\___ > |____/__|___| /__|_ \\___ >__| \____ | |__| |__| (____ /\___ >___ >
\/ \/ \/ \/ \/ \/ \/ \/ \/ \/
`

$3

This is a non-type script version + cli verification tool of the following code:
`
const ByteBuffer = require('bytebuffer');

public traceToLinkerdPackedHeader():string{
let flagBytes = [0, 0, 0, 0, 0, 0, 0, 6];
let serialized = ByteBuffer.concat([this.getByteArray(this.traceId.spanId),this.getByteArray(this.traceId.parentId), this.getByteArray(this.traceId.traceId), flagBytes]);

return serialized.toBase64();
}
private getByteArray(id: string ){
let array = Buffer.from(id, 'utf8');
let byteArray = [];
for (let i = 0; i < 16; i = i + 2) {
let parsed = parseInt(id.slice(i, i + 2), 16);
parsed = parsed & 255;

if (parsed > 127) {
parsed = -((parsed & 127) ^ 127) - 1;
}

byteArray.push(parsed);
}

return byteArray;
}

`

$3

Well, that is somewhat of a complicated, but at a high level, it is taking 3 input strings (presumably in utf8 encoding, or a string verson of a bytestring), and performing either a checksum, or compression algorithm using Bitwise Opperation to produce uniform base64 encoded string, spcific to linkerd.

For a raw breakdown of what the code is doing, see the BREAKDOWN.md doc.

$3

##### Install NVM, NPM, Nodejs

##### Install Node 8.X

`
nvm install 8
nvm alias default 8 # optional
`

##### Install This package (Start Here if you have npm and node installed)

`
npm install -g node-linkerd-trace

`

$3

`
node-linkerd-trace
``

###### Above should run with default values and print more usage