feat: add convert config command

[pront]

Motivation

This part of #18323.

I will use this command to help me with the above work and also, it can be used by customers who are interested in switching to YAML configs.

Summary

The main goal is to provide a starting point for config migration. The conversion is best effort. Notably:

• Comments from the original config are not preserved.
• Some default values are skipped and others are part of the output.
  • This is determined by each individual source/sink config.
  • If a field has the skip_serializing_if_default attribute defined then the converted output will not have entries with null values.
  • If the above attribute is defined and the value is equal to the default, then it won't be part of the output even if it was specified in the original config.

So the user of the command might want to:

1. add comments
2. remove entries with null values
3. (optional) add back default values

Example

Input TOML config:

# Commets are dropped.
#[api]
#enabled = true
#address = "127.0.0.1:8686"

data_dir = "/var/lib/vector/"

[sources.source0]
count = 9223372036854775807
format = "json"
interval = 1.0
type = "demo_logs"

[sources.source0.decoding]
codec = "bytes"

[sources.source0.framing]
method = "bytes"

[transforms.transform0]
inputs = ["source0"]
drop_on_abort = false
drop_on_error = false
metric_tag_values = "single"
reroute_dropped = false
runtime = "ast"
type = "remap"

[sinks.sink0]
inputs = ["transform0"]
target = "stdout"
type = "console"

[sinks.sink0.encoding]
codec = "json"

[sinks.sink0.healthcheck]
enabled = true

[sinks.sink0.buffer]
type = "memory"
max_events = 500
when_full = "block"

Command:

/Users/pavlos.rontidis/CLionProjects/vector/target/debug/vector convert-config  /Users/pavlos.rontidis/CLionProjects/vector/tests/data/cmd/config/config_2.toml   ~/CLionProjects/vector/pront_tests/config_2.toml

Output YAML config:

api:
  enabled: false
  address: 127.0.0.1:8686
  playground: true
schema:
  enabled: false
  validation: false
  log_namespace: null
hash: 113c7036a481ef48fa356baa5ad2cf205f90106515b0adca8cde1c7914d2ffc2
enterprise: null
global:
  data_dir: /var/lib/vector/
healthchecks:
  enabled: true
  require_healthy: false
sources:
  source0:
    type: demo_logs
    interval: 1.0
    count: 9223372036854775807
    format: json
    framing:
      method: bytes
    decoding:
      codec: bytes
    log_namespace: null
sinks:
  sink0:
    inputs:
    - component: transform0
      port: null
    healthcheck_uri: null
    healthcheck:
      enabled: true
      uri: null
    type: console
    target: stdout
    framing: null
    encoding:
      codec: json
transforms:
  transform0:
    inputs:
    - component: source0
      port: null
    type: remap
    source: null
    file: null
    metric_tag_values: single
    timezone: null
    drop_on_error: false
    drop_on_abort: false
    reroute_dropped: false
    runtime: ast
enrichment_tables: {}
tests: []
secret: {}
graceful_shutdown_duration: null

Followup

• Add the skip_serializing_if_default trait to various configs.

[netlify]

✅ Deploy Preview for vrl-playground canceled.

Name	Link
🔨 Latest commit	6c1e243
🔍 Latest deploy log	https://app.netlify.com/sites/vrl-playground/deploys/64f8bbe401ab3f00085f7703

[netlify]

✅ Deploy Preview for vector-project canceled.

Name	Link
🔨 Latest commit	6c1e243
🔍 Latest deploy log	https://app.netlify.com/sites/vector-project/deploys/64f8bbe465d87d0008bc432e

[datadog-vectordotdev]

Datadog Report

Branch report: pront/convert-config-command
Commit report: d8173cc

✅ vector: 0 Failed, 0 New Flaky, 1958 Passed, 0 Skipped, 1m 21.76s Wall Time

[bruceg]

A couple of smallish comments, but otherwise looks good.

[fuchsnj]

very cool!

[github-actions]

Regression Detector Results

Run ID: 2f674156-5846-4d0b-b6ff-5ca0f1000a9b
Baseline: 567de50
Comparison: 9cb0ca3
Total vector CPUs: 7

Explanation

A regression test is an integrated performance test for vector in a repeatable rig, with varying configuration for vector. What follows is a statistical summary of a brief vector run for each configuration across SHAs given above. The goal of these tests are to determine quickly if vector performance is changed and to what degree by a pull request.

Because a target's optimization goal performance in each experiment will vary somewhat each time it is run, we can only estimate mean differences in optimization goal relative to the baseline target. We express these differences as a percentage change relative to the baseline target, denoted "Δ mean %". These estimates are made to a precision that balances accuracy and cost control. We represent this precision as a 90.00% confidence interval denoted "Δ mean % CI": there is a 90.00% chance that the true value of "Δ mean %" is in that interval.

We decide whether a change in performance is a "regression" -- a change worth investigating further -- if both of the following two criteria are true:

1. The estimated |Δ mean %| ≥ 5.00%. This criterion intends to answer the question "Does the estimated change in mean optimization goal performance have a meaningful impact on your customers?". We assume that when |Δ mean %| < 5.00%, the impact on your customers is not meaningful. We also assume that a performance change in optimization goal is worth investigating whether it is an increase or decrease, so long as the magnitude of the change is sufficiently large.

2. Zero is not in the 90.00% confidence interval "Δ mean % CI" about "Δ mean %". This statement is equivalent to saying that there is at least a 90.00% chance that the mean difference in optimization goal is not zero. This criterion intends to answer the question, "Is there a statistically significant difference in mean optimization goal performance?". It also means there is no more than a 10.00% chance this criterion reports a statistically significant difference when the true difference in mean optimization goal is zero -- a "false positive". We assume you are willing to accept a 10.00% chance of inaccurately detecting a change in performance when no true difference exists.

The table below, if present, lists those experiments that have experienced a statistically significant change in mean optimization goal performance between baseline and comparison SHAs with 90.00% confidence OR have been detected as newly erratic. Negative values of "Δ mean %" mean that baseline is faster, whereas positive values of "Δ mean %" mean that comparison is faster. Results that do not exhibit more than a ±5.00% change in their mean optimization goal are discarded. An experiment is erratic if its coefficient of variation is greater than 0.1. The abbreviated table will be omitted if no interesting change is observed.

No interesting changes in experiment optimization goals with confidence ≥ 90.00% and |Δ mean %| ≥ 5.00%.

Fine details of change detection per experiment.

experiment	goal	Δ mean %	Δ mean % CI	confidence
http_to_http_acks	ingress throughput	+3.09	[+2.89, +3.30]	100.00%
syslog_regex_logs2metric_ddmetrics	ingress throughput	+2.57	[+2.22, +2.92]	100.00%
http_to_http_noack	ingress throughput	+1.91	[+1.74, +2.07]	100.00%
syslog_log2metric_splunk_hec_metrics	ingress throughput	+0.82	[+0.66, +0.99]	100.00%
http_to_s3	ingress throughput	+0.45	[+0.20, +0.70]	99.68%
splunk_hec_route_s3	ingress throughput	+0.41	[-0.14, +0.96]	78.31%
http_text_to_http_json	ingress throughput	+0.29	[+0.18, +0.41]	100.00%
syslog_loki	ingress throughput	+0.23	[+0.12, +0.34]	99.91%
datadog_agent_remap_datadog_logs_acks	ingress throughput	+0.20	[+0.07, +0.33]	99.05%
datadog_agent_remap_blackhole_acks	ingress throughput	+0.13	[+0.01, +0.25]	91.90%
file_to_blackhole	egress throughput	+0.05	[-1.11, +1.20]	5.24%
splunk_hec_indexer_ack_blackhole	ingress throughput	+0.01	[-0.15, +0.17]	7.47%
splunk_hec_to_splunk_hec_logs_noack	ingress throughput	-0.00	[-0.14, +0.13]	3.43%
http_to_http_json	ingress throughput	-0.00	[-0.06, +0.05]	9.50%
datadog_agent_remap_blackhole	ingress throughput	-0.14	[-0.25, -0.04]	97.51%
splunk_hec_to_splunk_hec_logs_acks	ingress throughput	-0.36	[-0.51, -0.21]	99.99%
otlp_grpc_to_blackhole	ingress throughput	-0.49	[-0.60, -0.39]	100.00%
syslog_humio_logs	ingress throughput	-0.74	[-0.87, -0.61]	100.00%
syslog_splunk_hec_logs	ingress throughput	-0.89	[-0.97, -0.81]	100.00%
fluent_elasticsearch	ingress throughput	-1.12	[-1.43, -0.81]	100.00%
datadog_agent_remap_datadog_logs	ingress throughput	-1.22	[-1.37, -1.07]	100.00%
enterprise_http_to_http	ingress throughput	-1.38	[-1.53, -1.22]	100.00%
socket_to_socket_blackhole	ingress throughput	-1.41	[-1.47, -1.35]	100.00%
otlp_http_to_blackhole	ingress throughput	-2.39	[-2.56, -2.22]	100.00%
syslog_log2metric_humio_metrics	ingress throughput	-2.51	[-2.63, -2.38]	100.00%