Add machinery to do client-side RDP license caching #47634
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Expose a Cgo interface for writing licenses to the agent's process storage.
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| case len(license) > 0: | ||
| log.InfoContext(context.Background(), "found existing RDP license") |
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what should happen in case of err == nil && len(license) == 0?
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That's not something I've commonly seen in Go code. It's generally safe to assume that a nil error means we're returning valid data.
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So why use additional case here? can we skip it and simply log after switch?
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I'm not sure I follow?
I want to be able to tell from the logs if:
- We know there wasn't an existing license.
- We know there was an existing license.
- We don't know if there was a license or not because we encountered an error.
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Right now the switch is not exhaustive, case where err == nil and len(license) == 0 will log nothing.
So, we either don't care about the length (we assume it's >0 when err==nil) and we can skip the length check (by either returning early in case of errors above and logging happy path outside of switch or changing last case to default) or we do care and should log something different in that case
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Fair enough, we can change the last case to a default case instead.
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We could error upon trying to write an empty license (if that's ever plausible) and treat an empty license as a not found error, too.
For what it's worth we seem to always avoid writing items with a blank value in the backend - nothing bad should happen, but...
| @@ -233,6 +235,31 @@ func (p *ProcessStorage) WriteTeleportVersion(ctx context.Context, version *semv | |||
| return nil | |||
| } | |||
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| func (p *ProcessStorage) rdpLicenseKey(majorVersion, minorVersion uint16, issuer, company, productID string) backend.Key { | |||
| return backend.NewKey("rdplicense", issuer, strconv.Itoa(int(majorVersion)), strconv.Itoa(int(minorVersion)), company, productID) | |||
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Are we ever going to list the licenses? If so, are we more likely to want to list them by issuer major minor company productid, or some other order?
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Order of the keys don't really matter as we don't ever need to list them. The only operation we need to support is "does a license exist for these specific values?"
| *data_out = nil | ||
| *len_out = 0 | ||
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| client, err := toClient(handle) | ||
| if err != nil { | ||
| return C.ErrCodeFailure | ||
| } | ||
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| issuer := C.GoString(req.issuer) | ||
| company := C.GoString(req.company) | ||
| productID := C.GoString(req.product_id) |
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We are currently recovering against panics in toClient; while that's pretty gross, should we be consistent and also check that req and the out pointers are not nil?
| case len(license) > 0: | ||
| log.InfoContext(context.Background(), "found existing RDP license") |
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We could error upon trying to write an empty license (if that's ever plausible) and treat an empty license as a not found error, too.
For what it's worth we seem to always avoid writing items with a blank value in the backend - nothing bad should happen, but...
Expose a Cgo interface for writing licenses to the agent's process storage.