Add OmniGCP

[AlCutter]

This PR adds a GCP-specific binary for running omniwitness, along with a Spanner-based persistence implementation, and a Secret Manager based signer.

$ go run ./cmd/gcp/omniwitness/ --signer_private_key_secret_name=projects/1234/secrets/privy/versions/1 --spanner=projects/myproject/instances/spanner/databases/db
I0820 13:48:27.709821  677822 main.go:83] Prometheus configured to listen on ":8081"
I0820 13:48:27.827359  677822 omniwitness.go:113] Added log "go.sum database tree": a32d071739c062f4973f1db8cc1069f517428d77105962b285bbf918c4062591
I0820 13:48:27.827394  677822 omniwitness.go:113] Added log "Armory Drive Prod 2": 48d31bf4bc3c95c7daddf7f8d33bb9ef1bff7500a40566eb56c97ff30eb6d44b
I0820 13:48:27.827418  677822 omniwitness.go:113] Added log "rekor.sigstore.dev - 3904496407287907110": c43a5887c927e0594e0a5feb87c2311ec86c3367613001b40dec552473aaa5dc
I0820 13:48:27.827437  677822 omniwitness.go:113] Added log "rekor.sigstore.dev - 2605736670972794746": 254283943e39c2a88e4d9185d4d7aa9f21afe369749872358204e8c25a00a80a
I0820 13:48:27.827451  677822 omniwitness.go:113] Added log "rekor.sigstore.dev - 1193050959916656506": 83650d970a8ad7c072dabb8d0d26d5a358b682fd43b432d39ccfbb7a200a6dba
I0820 13:48:27.827468  677822 omniwitness.go:113] Added log "developers.google.com/android/binary_transparency/0": 2371c7aa76ca0d588c7f21317b789071bb63593bd2c3d7b02ca5842f03680fda
I0820 13:48:27.827484  677822 omniwitness.go:113] Added log "developers.google.com/android/binary_transparency/google1p/0": f149a2505f9807fa39641c568f6161b2d496a4e43833350399330791f97501b9
I0820 13:48:27.827497  677822 omniwitness.go:113] Added log "lvfs": fabf738c02d466c9aef96e226f02bcc193f7093fd41995db036349ff38715e54
I0820 13:48:27.827511  677822 omniwitness.go:113] Added log "transparency.dev/armored-witness/firmware_transparency/prod/1": d4be095420ee6b18b699b2958a609f754f4784c81eda1e6d8f726b97a86e076d
I0820 13:48:27.827524  677822 omniwitness.go:113] Added log "transparency.dev/armored-witness/firmware_transparency/ci/2": 6df87b390820f503021ae2bef14dc582f23af18f158713982f243b6e414252d6
I0820 13:48:27.827537  677822 omniwitness.go:113] Added log "transparency.dev/armored-witness/firmware_transparency/ci/3": 0b963db2162e516836b4afbf8ff75aca120af717d3b93a332464cd5af4146e99
I0820 13:48:27.827551  677822 omniwitness.go:113] Added log "sigsum.org/v1/tree/44ad38f8226ff9bd27629a41e55df727308d0a1cd8a2c31d3170048ac1dd22a1": e5a19e2a99bc3fe4968b64bedaf64e43a9888e485320746cc46ade52ea33a328
I0820 13:48:27.827564  677822 omniwitness.go:113] Added log "tlog.andxor.it": a827ae6361d25a3349faef47a9a5ed64a3886b68e5b14284d3ee7ee79c0cc26e
I0820 13:48:30.994505  677822 omniwitness.go:198] HTTP server-shutdown goroutine started
I0820 13:48:30.994499  677822 omniwitness.go:155] Feeder "rekor.sigstore.dev - 2605736670972794746" goroutine will start after spread delay of 37.562068809s
I0820 13:48:30.994538  677822 omniwitness.go:155] Feeder "Armory Drive Prod 2" goroutine will start after spread delay of 55.700126271s
I0820 13:48:30.994529  677822 omniwitness.go:155] Feeder "go.sum database tree" goroutine will start after spread delay of 2.413955743s
I0820 13:48:30.994555  677822 omniwitness.go:155] Feeder "developers.google.com/android/binary_transparency/0" goroutine will start after spread delay of 33.304139458s
I0820 13:48:30.994549  677822 omniwitness.go:155] Feeder "lvfs" goroutine will start after spread delay of 24.085008625s
I0820 13:48:30.994572  677822 omniwitness.go:155] Feeder "transparency.dev/armored-witness/firmware_transparency/ci/3" goroutine will start after spread delay of 52.01526897s
I0820 13:48:30.994585  677822 omniwitness.go:155] Feeder "tlog.andxor.it" goroutine will start after spread delay of 47.534911705s
I0820 13:48:30.994590  677822 omniwitness.go:155] Feeder "developers.google.com/android/binary_transparency/google1p/0" goroutine will start after spread delay of 33.084219325s
I0820 13:48:30.994571  677822 omniwitness.go:155] Feeder "transparency.dev/armored-witness/firmware_transparency/prod/1" goroutine will start after spread delay of 4.12085867s
I0820 13:48:30.994609  677822 omniwitness.go:192] HTTP server goroutine started
I0820 13:48:30.994614  677822 omniwitness.go:155] Feeder "rekor.sigstore.dev - 3904496407287907110" goroutine will start after spread delay of 20.955473027s
I0820 13:48:30.994594  677822 omniwitness.go:155] Feeder "rekor.sigstore.dev - 1193050959916656506" goroutine will start after spread delay of 56.116787319s
I0820 13:48:30.994643  677822 omniwitness.go:155] Feeder "transparency.dev/armored-witness/firmware_transparency/ci/2" goroutine will start after spread delay of 22.113599597s
I0820 13:48:33.409563  677822 omniwitness.go:159] Feeder "go.sum database tree" running
I0820 13:48:35.115521  677822 omniwitness.go:159] Feeder "transparency.dev/armored-witness/firmware_transparency/prod/1" running
I0820 13:48:51.950149  677822 omniwitness.go:159] Feeder "rekor.sigstore.dev - 3904496407287907110" running
I0820 13:48:53.109303  677822 omniwitness.go:159] Feeder "transparency.dev/armored-witness/firmware_transparency/ci/2" running
I0820 13:48:55.079638  677822 omniwitness.go:159] Feeder "lvfs" running
I0820 13:49:04.079074  677822 omniwitness.go:159] Feeder "developers.google.com/android/binary_transparency/google1p/0" running
I0820 13:49:04.299170  677822 omniwitness.go:159] Feeder "developers.google.com/android/binary_transparency/0" running

Towards #386

[codecov-commenter]

Codecov Report

❌ Patch coverage is 27.21893% with 123 lines in your changes missing coverage. Please review.
✅ Project coverage is 19.57%. Comparing base (3c58af4) to head (d914c94).
⚠️ Report is 199 commits behind head on main.

Files with missing lines	Patch %	Lines
cmd/gcp/omniwitness/main.go	0.00%	56 Missing ⚠️
cmd/gcp/omniwitness/persistence.go	55.42%	25 Missing and 12 partials ⚠️
cmd/gcp/omniwitness/secret_manager.go	0.00%	30 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (3c58af4) and HEAD (d914c94). Click for more details.

HEAD has 2 uploads less than BASE

Flag	BASE (3c58af4)	HEAD (d914c94)
	4	2

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #385       +/-   ##
===========================================
- Coverage   51.05%   19.57%   -31.48%     
===========================================
  Files          11       28       +17     
  Lines         903     1977     +1074     
===========================================
- Hits          461      387       -74     
- Misses        374     1526     +1152     
+ Partials       68       64        -4     

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