| // Copyright 2023 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Package counter implements a simple counter system for collecting |
| // totally public telemetry data. |
| // |
| // There are two kinds of counters, simple counters and stack counters. |
| // Simple counters are created by New(<counter-name>). |
| // Stack counters are created by NewStack(<counter-name>, depth). |
| // Both are incremented by calling Inc(). |
| // |
| // Counter files are stored in LocalDir(). Their content can be accessed |
| // by Parse(). |
| // |
| // Simple counters are very cheap. Stack counters are more |
| // expensive, as they require parsing the stack. |
| // (Stack counters are implemented as a set of regular counters whose names |
| // are the concatenation of the name and the stack trace. There is an upper |
| // limit on the size of this name, about 4K bytes. If the name is too long |
| // the stack will be truncated and "truncated" appended.) |
| // |
| // When counter files expire they are turned into reports by the upload package. |
| // The first time any counter file is created for a user, a random |
| // day of the week is selected on which counter files will expire. |
| // For the first week, that day is more than 7 days (but not more than |
| // two weeks) in the future. |
| // After that the counter files expire weekly on the same day of |
| // the week. |
| package counter |
