fix(backend): don't raise false-positive alerts for alertmanagers wit…

[prymitive]

…h no cluster name

[prymitive]

Go benchmark diff

name                               old time/op        new time/op        delta
pkg:github.com/prymitive/karma/cmd/karma goos:linux goarch:amd64
Compress/Run-2                           5.31ms ± 1%        5.33ms ± 1%  +0.46%  (p=0.043 n=10+10)
Decompress/Run-2                         3.65ms ± 2%        3.65ms ± 1%    ~     (p=0.684 n=10+10)
CompressionAndDecompression/Run-2        9.25ms ± 1%        9.32ms ± 1%  +0.78%  (p=0.003 n=10+9)
PullAlerts/0.19.0-2                      6.13ms ± 2%        6.31ms ± 1%  +2.83%  (p=0.000 n=10+10)
AlertsAPIMisses/0.19.0-2                 1.49ms ± 3%        1.53ms ± 2%  +2.68%  (p=0.003 n=10+10)
AlertsAPIHits/0.19.0-2                    966µs ± 2%         966µs ± 2%    ~     (p=0.661 n=9+10)
pkg:github.com/prymitive/karma/internal/alertmanager goos:linux goarch:amd64
DedupAlerts/Run-2                         129µs ± 1%         130µs ± 2%    ~     (p=0.247 n=10+10)
DedupAutocomplete/Run-2                  59.0µs ± 1%        59.5µs ± 1%  +0.75%  (p=0.015 n=10+10)
DedupColors/Run-2                        16.6µs ± 3%        16.5µs ± 1%    ~     (p=0.529 n=10+10)

name                               old %/compression  new %/compression  delta
pkg:github.com/prymitive/karma/cmd/karma goos:linux goarch:amd64
Compress/Run-2                             0.04 ± 0%          0.04 ± 0%    ~     (all equal)

name                               old B/alloc        new B/alloc        delta
pkg:github.com/prymitive/karma/cmd/karma goos:linux goarch:amd64
Compress/Run-2                            4.99M ± 0%         4.99M ± 0%  -0.08%  (p=0.000 n=9+9)
Decompress/Run-2                          3.10M ± 0%         3.09M ± 0%  -0.24%  (p=0.000 n=10+8)
CompressionAndDecompression/Run-2         5.00M ± 0%         4.99M ± 0%  -0.13%  (p=0.000 n=9+10)
PullAlerts/0.19.0-2                       3.06M ± 0%         3.06M ± 0%  -0.08%  (p=0.000 n=9+9)
AlertsAPIMisses/0.19.0-2                  3.46M ± 0%         3.45M ± 0%  -0.07%  (p=0.000 n=9+9)
AlertsAPIHits/0.19.0-2                    3.42M ± 0%         3.41M ± 0%  -0.07%  (p=0.000 n=9+9)

name                               old alloc/op       new alloc/op       delta
pkg:github.com/prymitive/karma/cmd/karma goos:linux goarch:amd64
Compress/Run-2                           1.13MB ± 0%        1.13MB ± 0%    ~     (all equal)
Decompress/Run-2                         4.24MB ± 0%        4.24MB ± 0%    ~     (p=0.656 n=10+10)
CompressionAndDecompression/Run-2        5.38MB ± 0%        5.38MB ± 0%    ~     (all equal)
PullAlerts/0.19.0-2                      1.27MB ± 0%        1.27MB ± 0%  -0.01%  (p=0.043 n=10+10)
AlertsAPIMisses/0.19.0-2                 1.29MB ± 0%        1.29MB ± 0%    ~     (p=0.796 n=10+10)
AlertsAPIHits/0.19.0-2                    317kB ± 1%         318kB ± 0%    ~     (p=0.447 n=10+9)
pkg:github.com/prymitive/karma/internal/alertmanager goos:linux goarch:amd64
DedupAlerts/Run-2                        73.7kB ± 0%        73.7kB ± 0%    ~     (p=0.312 n=10+10)
DedupAutocomplete/Run-2                  27.2kB ± 0%        27.2kB ± 0%    ~     (p=0.127 n=10+10)
DedupColors/Run-2                        7.36kB ± 0%        7.36kB ± 0%    ~     (p=0.108 n=10+9)

name                               old allocs/op      new allocs/op      delta
pkg:github.com/prymitive/karma/cmd/karma goos:linux goarch:amd64
Compress/Run-2                             31.0 ± 0%          31.0 ± 0%    ~     (all equal)
Decompress/Run-2                           80.0 ± 0%          80.0 ± 0%    ~     (all equal)
CompressionAndDecompression/Run-2           111 ± 0%           111 ± 0%    ~     (all equal)
PullAlerts/0.19.0-2                       22.5k ± 0%         22.5k ± 0%    ~     (all equal)
AlertsAPIMisses/0.19.0-2                  6.08k ± 0%         6.08k ± 0%    ~     (p=1.000 n=10+10)
AlertsAPIHits/0.19.0-2                    2.36k ± 0%         2.36k ± 0%    ~     (p=0.650 n=10+10)
pkg:github.com/prymitive/karma/internal/alertmanager goos:linux goarch:amd64
DedupAlerts/Run-2                           415 ± 0%           415 ± 0%    ~     (all equal)
DedupAutocomplete/Run-2                     114 ± 0%           114 ± 0%    ~     (all equal)
DedupColors/Run-2                          35.0 ± 0%          35.0 ± 0%    ~     (all equal)