Support upload from named pipes (#748)

Named pipes report file size as 0, which leads to reading the whole
content into memory (0 is less than 64K). This adds additional check to
make sure that the passed in path is not a named pipe, and in that case
opts for the create-temp-file-to-gzip code path.

When running on GitHub Actions infrastructure on `windows` node, named
pipes can be created using `mkfifo` from MSYS2. In that case `fs.Stats`s
`isFIFO()` returns `false`, and not `true` as expected. This case is
detected by `process.platform` being `win32` and the passed file having
length of 0.

As a side note, when MSYS2's `mkfifo` is run, a pipe file is created:

```
prw-rw-rw- 1 User None  0 Mar 31 12:58 pipe
```

If `fs.stat` is invoked at this point `ENOENT` error will be thrown. As
soon as the pipe is written to, this pipe file is replaced by two same-
named files:

```
-rw-r--r-- 1 User None  0 Mar 31 13:00 pipe
-rw-r--r-- 1 User None  0 Mar 31 13:00 pipe
```

And at this point `fs.stat` `isFIFO()` returns `false`. Even though the
file acts as a named pipe.

packages/artifact/__tests__/upload.test.ts

@@ -2,6 +2,10 @@ import * as http from 'http'
 import * as io from '../../io/src/io'
 import * as net from 'net'
 import * as path from 'path'
+import {mocked} from 'ts-jest/utils'
+import {exec, execSync} from 'child_process'
+import {createGunzip} from 'zlib'
+import {promisify} from 'util'
 import {UploadHttpClient} from '../src/internal/upload-http-client'
 import * as core from '@actions/core'
 import {promises as fs} from 'fs'
@@ -174,6 +178,56 @@ describe('Upload Tests', () => {
     expect(uploadResult.uploadSize).toEqual(expectedTotalSize)
   })
 
+  function hasMkfifo(): boolean {
+    try {
+      // make sure we drain the stdout
+      return execSync('which mkfifo').toString().length > 0
+    } catch (e) {
+      return false
+    }
+  }
+  const withMkfifoIt = hasMkfifo() ? it : it.skip
+  withMkfifoIt(
+    'Upload Artifact with content from named pipe - Success',
+    async () => {
+      // create a named pipe 'pipe' with content 'hello pipe'
+      const content = Buffer.from('hello pipe')
+      const pipeFilePath = path.join(root, 'pipe')
+      await promisify(exec)('mkfifo pipe', {cwd: root})
+      // don't want to await here as that would block until read
+      fs.writeFile(pipeFilePath, content)
+
+      const artifactName = 'successful-artifact'
+      const uploadSpecification: UploadSpecification[] = [
+        {
+          absoluteFilePath: pipeFilePath,
+          uploadFilePath: `${artifactName}/pipe`
+        }
+      ]
+
+      const uploadUrl = `${getRuntimeUrl()}_apis/resources/Containers/13`
+      const uploadHttpClient = new UploadHttpClient()
+      const uploadResult = await uploadHttpClient.uploadArtifactToFileContainer(
+        uploadUrl,
+        uploadSpecification
+      )
+
+      // accesses the ReadableStream that was passed into sendStream
+      // eslint-disable-next-line @typescript-eslint/unbound-method
+      const stream = mocked(HttpClient.prototype.sendStream).mock.calls[0][2]
+      expect(stream).not.toBeNull()
+      // decompresses the passed stream
+      const data: Buffer[] = []
+      for await (const chunk of stream.pipe(createGunzip())) {
+        data.push(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk as string))
+      }
+      const uploaded = Buffer.concat(data)
+
+      expect(uploadResult.failedItems.length).toEqual(0)
+      expect(uploaded).toEqual(content)
+    }
+  )
+
   it('Upload Artifact - Failed Single File Upload', async () => {
     const uploadSpecification: UploadSpecification[] = [
       {