This change adds a new flag to `opa run` to allow
users to specify a list of enabled TLS 1.0–1.2 cipher
suites. This allows users to control the cipher suites
the OPA server supports during a TLS handshake.
Signed-off-by: Ashutosh Narkar <anarkar4387@gmail.com>
Regularly clean up of cache entries that have expired for a more efficient use of memory.
Introduce two new parameters to tune clean up frequency and threshold for forced FIFO eviction.
Fixes#5320
Signed-off-by: Rudrakh Panigrahi <rudrakh97@gmail.com>
This was missed in https://github.com/open-policy-agent/opa/pull/6415https://github.com/open-policy-agent/opa/actions/runs/7194437460/job/19595009978?pr=6476
We have a warning of this data race here:
```
==================
WARNING: DATA RACE
Write at 0x00c009b562e8 by goroutine 1815:
github.com/open-policy-agent/opa/server.(*Server).reloadTLSConfig()
/src/server/certs.go:65 +0x608
github.com/open-policy-agent/opa/server.(*Server).getListener.(*Server).certLoopNotify.func2()
/src/server/certs.go:174 +0x434
github.com/open-policy-agent/opa/server.TestCertPoolReloading.func1()
/src/server/server_test.go:5105 +0x4f
github.com/open-policy-agent/opa/server.TestCertPoolReloading.func2()
/src/server/server_test.go:5108 +0x41
Previous read at 0x00c009b562e8 by goroutine 1824:
github.com/open-policy-agent/opa/server.(*Server).getListenerForHTTPSServer.func1()
/src/server/server.go:649 +0x145
crypto/tls.(*Conn).readClientHello()
/usr/local/go/src/crypto/tls/handshake_server.go:149 +0x97d
crypto/tls.(*Conn).serverHandshake()
/usr/local/go/src/crypto/tls/handshake_server.go:42 +0x64
crypto/tls.(*Conn).serverHandshake-fm()
<autogenerated>:1 +0x47
crypto/tls.(*Conn).handshakeContext()
/usr/local/go/src/crypto/tls/conn.go:1552 +0x615
crypto/tls.(*Conn).HandshakeContext()
/usr/local/go/src/crypto/tls/conn.go:1492 +0x16b8
net/http.(*conn).serve()
/usr/local/go/src/net/http/server.go:1891 +0x16c0
net/http.(*Server).Serve.func3()
/usr/local/go/src/net/http/server.go:3086 +0x4f
```
Signed-off-by: Charlie Egan <charlie@styra.com>
The partial query parameter has been marked as deprecated since
v0.23.0. It's also removed from the docs since that time.
Fixes: #2266
Signed-off-by: Ashutosh Narkar <anarkar4387@gmail.com>
http_request_duration has fixed, hardcoded number of buckets with no possibility to tweak them
For cases when the most of the latencies are above 1ms, with only 4 available buckets there's no good insight on OPA's performance.
This implementation:
- adds the possibility for the buckets to be configurable in ```server.metrics.prom.http_request_duration_seconds.buckets``` key
- it's not a breaking change, if the buckets are not present in the configuration, the metric is configured with the existing values as a fallback
Signed-off-by: aarnautu <aarnautu@adobe.com>
This test case exercises the scenario when a bundle is being written
to the store (ie. active write transaction) and the OPA server handling
a policy eval request at the same time. The former should not block
the later.
Fixes: #4792
Signed-off-by: Ashutosh Narkar <anarkar4387@gmail.com>
Currently we parse store modules irrespective of whether
there are modules on the Rego object. This will result in
the compilation of those modules which triggers the bundle
activation flow. Now as part of the module compilation
we interact with the compiler's modules and run compilation
on the input modules. If let's say there are concurrent health
check requests (ie. /v1/health), this could result in a race
during the compilation process while working with the compiler's
modules.
This change avoids this situation by skipping parsing of the store
modules when none are set on the Rego object. The assumption this
change makes is that while using the rego package the compiler and
store are kept in-sync.
Fixes: #5868
Signed-off-by: Ashutosh Narkar <anarkar4387@gmail.com>
This came up in the discussion of the previous cleanup PR, but I hadn't
gotten around to include it back then.
Signed-off-by: Stephan Renatus <stephan@styra.com>
Currently if OPA listens on a Unix socket, the socket
file is created with 755 permissions. So if OPA is deployed
on k8s for example and the socket path is shared
via a volume between pods, due to the default permissions,
the socket will not be reachable for the caller. One way around
this is to match the user id for the OPA and caller containers
but that is not always possible.
This change adds a new flag to the OPA runtime that allows
to configure the permission of the socket file. In the
k8s scenario, if the file permission is updated to 777
for instance, the caller will be able to connect to OPA via
the socket.
Signed-off-by: Ashutosh Narkar <anarkar4387@gmail.com>
Currently OPA's decision logs do not include the trace
and span identifier associated with a given request
handled by the server. This information if available
can be helpful to correlate logs and trace data.
This change updates the decision log format to now
include the trace and span identifier if present.
Fixes: #5230
Signed-off-by: Ashutosh Narkar <anarkar4387@gmail.com>
Currently when OPA's HTTP server rejects requests per
the authz policy, this is not accounted for via the management APIs.
This change adds that count in the metric registry that is
part of the Status API for more visibility.
Fixes: #3378
Signed-off-by: Ashutosh Narkar <anarkar4387@gmail.com>
When using OPA TLS authorization, authz policy authors will now have
access to the client certificates presented as part of the TLS
connection. This new data will be available under the key `client_certificates`.
The existing functionality where `identity` is set to the Subject RDN Sequence
is left unchanged.
When using x.509 SVIDs the SPIFFEID is presented as in the SANs of the
certificate. So this change makes that data available should users
require it. It also makes other information about the client cert
available to authz policy too.
Signed-off-by: Charlie Egan <charlie@styra.com>
It is available for the following REST API endpoints:
- GET & POST HTTP methods on /v0/data & /v1/data endpoints
- POST HTTP method on /v1/compile endpoint
HTTP clients can optionally:
- send 'Accept-Encoding: gzip' header and expect a gzip compressed body and a Content-Encoding: gzip response header. The server will send the content encoded as gzip only after a threshold defined by server.encoding.gzip.min_length (default value is 1024). If the size is below the threshold, the body is not compressed
- send 'Content-Encoding: gzip' header and a gzip compressed body and expect the server to correctly interpret the request
Fixes#5310
Signed-off-by: aarnautu <aarnautu@adobe.com>
Similar to how https://github.com/open-policy-agent/opa/pull/5596
allowed streaming JSON in the response, do the same for the request.
This has potentially bigger benefits, as the incoming request is
commonly larger than the response (admission control, terraform, etc).
Signed-off-by: Anders Eknert <anders@styra.com>
Just s small cleanup in the server handler code. Ctx is for
request-scoped data, so let's put the decision ID there, too.
Our Eval and Log helper methods have way too many arguments already.
Signed-off-by: Stephan Renatus <stephan@styra.com>
When sending JSON back to the client — and we do a lot of that, use
the streaming implementation of json.Encode rather than marshalling
the data into an intermediate byte array.
One curious detail here is that the streaming implementation
uses newlines to mark the end of the stream, so a few unit tests had
to be updated to expect this. Previously we would only emit a trailing
newline if "pretty" was configured.
Signed-off-by: Anders Eknert <anders@styra.com>
* [rego] Check store modules before skipping parsing
Fixes https://github.com/open-policy-agent/opa/issues/5511
This change will cause the operation to be timed if the store
modules have already all been compiled and there are no
rawModules. This might be undesirable.
Signed-off-by: Charlie Egan <charlie@styra.com>
Since "document missing or undefined" caused confusion, we can be
more helpful and report whether the default decision document is
missing, or whether it's there but undefined. I would probably have
preferred for undefined to just result in an empty/undefined result,
but that'd be quite a breaking change at this point in time, so
hopefully this can at least make things a little less convoluted.
Fixes#5344
Signed-off-by: Anders Eknert <anders@eknert.com>
This is the OPA side of #4290. It will allow the envoy plugin to wire
the TraceProvider into the gRPC handlers.
Signed-off-by: vinhph0906 <vinhph0906@gmail.com>
Today it is not possible to correlate the decision log with
other types of logs (server, print, etc.) when the server log
level is >= INFO. The log correlation could be helpful in
troubleshooting.
A solution is to add a common attribute in all logs to make
the log correlation possible, so adding the req_id attribute
on decision logs, when server log level is >= INFO, will make it
possible.
Fixes: #5006
* Add documentation about decision log req_id attribute
The documentation purpose is to explain the relation with
others logs, how it could be used, and when it is included
on decision logs.
Signed-off-by: Humberto Corrêa da Silva <humbertoc_silva@hotmail.com>
This change allows rules to have string prefixes in their heads -- we've
come to call them "ref heads".
String prefixes means that where before, you had
package a.b.c
allow = true
you can now have
package a
b.c.allow = true
This allows for more concise policies, and different ways to structure
larger rule corpuses.
Backwards-compatibility:
- There are code paths that accept ast.Module structs that don't necessarily
come from the parser -- so we're backfilling the rule's Head.Reference
field from the Name when it's not present.
This is exposed through (Head).Ref() which always returns a Ref.
This also affects the `opa parse` "pretty" output:
With x.rego as
package x
import future.keywords
a.b.c.d if true
e[x] if true
we get
$ opa parse x rego
module
package
ref
data
"x"
import
ref
future
"keywords"
rule
head
ref
a
"b"
"c"
"d"
true
body
expr index=0
true
rule
head
ref
e
x
true
body
expr index=0
true
Note that
Name: e
Key: x
becomes
Reference: e[x]
in the output above (since that's how we're parsing it, back-compat edge cases aside)
- One special case for backcompat is `p[x] { ... }`:
rule | ref | key | value | name
------------------------+-------+-----+-------+-----
p[x] { ... } | p | x | nil | "p"
p contains x if { ... } | p | x | nil | "p"
p[x] if { ... } | p[x] | nil | true | ""
For interpreting a rule, we now have the following procedure:
1. if it has a Key, it's a multi-value rule; and its Ref defines the set:
Head{Key: x, Ref: p} ~> p is a set
^-- we'd get this from `p contains x if true`
or `p[x] { true }` (back compat)
2. if it has a Value, it's a single-value rule; its Ref may contain vars:
Head{Ref: p.q.r[s], Value: 12} ~> body determines s, `p.q.r.[s]` is 12
^-- we'd get this from `p.q.r[s] = 12 { s := "whatever" }`
Head{Key: x, Ref: p[x], Value: 3} ~> `p[x]` has value 3, `x` is determined
by the rule body
^-- we'd get this from `p[x] = 3 if x := 2`
or `p[x] = 3 { x := 2 }` (back compat)
Here, the Key isn't used, it's present for backwards compatibility: for ref-
less rule heads, `p[x] = 3` used to be a partial object: key x, value 3,
name "p"
- The destinction between complete rules and partial object rules disappears.
They're both single-value rules now.
- We're now outputting the refs of the rules completely in error messages, as
it's hard to make sense of "rule r" when there's rule r in package a.b.c and
rule b.c.r in package a.
Restrictions/next steps:
- Support for ref head rules in the REPL is pretty poor so far. Anything that
works does so rather accidentally. You should be able to work with policies
that contain ref heads, but you cannot interactively define them.
This is because before, we'd looked at REPL input like
p.foo.bar = true
and noticed that it cannot be a rule, so it's got to be a query. This is no
longer the case with ref heads.
- Currently vars in Refs are only allowed in the last position. This is expected
to change in the future.
- Also, for multi-value rules, we can not have a var at all -- so the following
isn't supported yet:
p.q.r[s] contains t if { ... }
-----
Most of the work happens when the RuleTree is derived from the ModuleTree -- in
the RuleTree, it doesn't matter if a rule was `p` in `package a.b.c` or `b.c.p`
in `package a`.
As such, the planner and wasm compiler hasn't seen that many adaptations:
- We're putting rules into the ruletree _including_ the var parts, so
p.q.a = 1
p.q.[x] = 2 { x := "b" }
end up in two different leaves:
p
`-> q
`-> a = 1
`-> [x] = 2`
- When planing a ref, we're checking if a rule tree node's children have
var keys, and plan "one level higher" accordingly:
Both sets of rules, p.q.a and p.q[x] will be planned into one function
(same as before); and accordingly return an object {"a": 1, "b": 2}
- When we don't have vars in the last ref part, we'll end up planning
the rules separately. This will have an effect on the IR.
p.q = 1
p.r = 2
Before, these would have been one function; now, it's two. As a result,
in Wasm, some "object insertion" conflicts can become "var assignment
conflicts", but that's in line with the now-new view of "multi-value"
and "single-value" rules, not partial {set/obj} vs complete.
* planner: only check ref.GroundPrefix() for optimizations
In a previous commit, we've only mapped
p.q.r[7]
as p.q.r; and as such, also need to lookup the ref
p.q.r[__local0__]
via p.q.r
(I think. Full disclosure: there might be edge cases here that are unaccounted
for, but right now, I'm aiming for making the existing tests green...)
New compiler stage:
In the compiler, we're having a new early rewriting step to ensure that the
RuleTree's keys are comparible. They're ast.Value, but some of them cause us
grief:
- ast.Object cannot be compared structurally; so
_, ok := map[ast.Value]bool{ast.NewObject([2]*ast.Term{ast.StringTerm("foo"), ast.StringTerm("bar")}): true}[ast.NewObject([2]*ast.Term{ast.StringTerm("foo"), ast.StringTerm("bar")})]
`ok` will never be true here.
- ast.Ref is a slice type, not hashable, so adding that to the RuleTree would
cause a runtime panic:
p[y.z] { y := input }
is now rewritten to
p[__local0__] { y := input; __local0__ := y.z }
This required moving the InitLocalVarGen stage up the chain, but as it's still
below ResolveRefs, we should be OK.
As a consequence, we've had to adapt `oracle` to cope with that rewriting:
1. The compiler rewrites rule head refs early because the rule tree expects
only simple vars, no refs, in rule head refs. So `p[x.y]` becomes
`p[local] { local = x.y }`
2. The oracle circles in on the node it's finding the definition for based
on source location, and the logic for doing that depends on unaltered
modules.
So here, (2.) is relaxed: the logic for building the lookup node stack can
now cope with generated statements that have been appended to the rule bodies.
There is a peculiarity about ref rules and extents:
See the added tests: having a ref rule implies that we get an empty object
in the full extent:
package p
foo.bar if false
makes the extent of data.p: {"foo": {}}
This is somewhat odd, but also follows from the behaviour we have right now
with empty modules:
package p.foo
bar if false
this also gives data.p the extent {"foo": {}}.
This could be worked around by recording, in the rule tree, when a node was
added because it's an intermediary with no values, but only children.
Signed-off-by: Stephan Renatus <stephan.renatus@gmail.com>
This would be useful for us for two immediate use cases:
1. Show how and why rules failed in more detail in verbose tooling,
we can show the unification happening step by step.
2. We can trace which parts of the input document were used, if we
add `Location` info those terms.
However, I think it's generally useful for debugging tools.
This increases verbosity in the explain logs, so we decided to add a new explain
mode `debug` in addition to the existing `full`, `notes`, `fails`, `off` modes.
This can be set using the `--explain=debug` flag on the CLI, or by using `trace
debug` in the REPL.
Signed-off-by: Jasper Van der Jeugt <m@jaspervdj.be>
This commit integrates the non-deterministic builtins caching system
into decision logging, both in the server and sdk packages. Some
reworking of the NDBCache's serialization format were required to
accommodate this. The feature is disabled by default, and must be
opted into by user configuration.
The feature can be enabled via a top-level config key:
nd_builtin_cache=true
The NDBCache is exposed to the masking system under the
`/nd_builtin_cache` path, which allows masking or dropping sensitive
values from decision logs selectively.
Note: If a decision log event exceeds the `upload_size_limit_bytes`
value for the OPA instance, OPA will reattempt uploading it, after
dropping the NDBCache from the event. This behavior will trigger a log
error, and will increment the `decision_logs_nd_builtin_cache_dropped`
metrics counter.
Fixes: #1514
Signed-off-by: Philip Conrad <philipaconrad@gmail.com>
Before, we'd only check if the NEW policy path was owned by a bundle. Now,
we'll also check if the to-be-updated policy is owned by a bundle. If so,
return an error.
Fixes#4846
Signed-off-by: Stephan Renatus <stephan.renatus@gmail.com>
Before, the option InterQueryCache(...) passed to the authorizer's config
had set it to `nil` -- it wasn't set up yet.
Now, the ordering allows for caching in the system authz policies.
Fixes#4829.
Signed-off-by: Stephan Renatus <stephan.renatus@gmail.com>
Currently bundles are loaded into memory entirely
even when disk storage is used. Then the parsed content
is written to the store. Deserializing data into Go structs
is memory consuming and even if user has configured disk
storage, OPA is still bound by the amount of memory
assigned to it. This change adds a new lazy loading mode
wherein the entire data is not deserialized while bundle
reading and hence if the bundle contains large data files
and the user has enabled disk storage, OPA should be
able to handle this scenario w/o running OOM.
Fixes: #4539
Signed-off-by: Ashutosh Narkar <anarkar4387@gmail.com>
This commit adds a new flag to the opa bench command which
allows users to run benchmarks against a running OPA server.
This mode can be used to evaluate the additional overhead the
server is going to introduce.
Co-authored-by: Anders Eknert anders@eknert.com
Signed-off-by: Ashutosh Narkar <anarkar4387@gmail.com>
Currently a write transaction on the store is opened
inside the query API handler (ie. v1DataPost). What this
means is if the user wants to evaluate a policy while
OPA is activating a bundle, the api request would block
trying to open a write txn on the store till the bundle
was activated. If OPA is activating a large bundle,
the write lock is held longer and hence the client would
notice the latency in OPA's API response. This change updates
the query handler to open a read txn on the store which was
the case pre-v0.39.0.
Signed-off-by: Ashutosh Narkar <anarkar4387@gmail.com>
This package is deprecated, archived, and in maintenance mode, since Go
errors support wrapping natively.
For #2152.
Signed-off-by: Jason Hall <jason@chainguard.dev>
A bunch of smaller follow-up tasks to #4381.
* storage/disk_test: check invalid patches with wildcard partition, too
* docs/disk: add caveat re: bundles loaded into memory
* storage/disk: auto-manage /system partitions
If these are found in the user-provided partitions, we'll error out.
* storage/disk: pretty-print partitions with "*" instead of %2A
* storage/disk: respect wildcard-replacement in partition validation
It is now allowed to replace a partition like
/foo/bar
by
/foo/*
also if multiple wildcards are used.
Caveats:
You cannot add a wildcard partition like /*/*, since it would overlap
the managed "/system/*" partition.
When attempting to go back from /foo/* to /foo/bar, an error is
raised _unconditionally_ -- we could check the existing data, but
currently don't.
* storage/disk: check prefix when adding wildcard partitions
The previously done check would have falsely returned that there is no problem
when adding a wildcard partition: lookup of "/foo/*" with '*' not interpreted
as a wildcard, but as a string, would yield a not-found, even if there was any
data under /foo/.
Now, we'll check the prefix-until-wildcard. It's more cautious than
theoretically necessary, but safe.
Signed-off-by: Stephan Renatus <stephan.renatus@gmail.com>
With this change, the disk backend (badger) becomes available for
use with the OPA runtime properly:
It can be configured using the `storage.disk` key in OPA's config
(see included documentation).
When enabled,
- any data or policies stored with OPA will persist over restarts
- per-query metrics related to disk usage are reported
- Prometheus metrics per storage operation are exported
The main intention behind this feature is to optimize memory usage:
OPA can now operate on more data than fits into the allotted memory
resources. It is NOT meant to be used as a primary source of truth:
there are no backup/restore or desaster recovery procedures -- you
MUST secure the means to restore the data stored with OPA's disk
storage by yourself.
See also #4014. Future improvements around bundle loading are
planned.
Some notes on details:
storage/disk: impose same locking regime used with inmem
With this setup, we'll ensure:
- there is only one open write txn at a time
- there are any number of open read txns at a time
- writes are blocked when reads are inflight
- during a commit (and triggers being run), no read txns can be created
This is to ensure the same atomic policy update semantics when using
'disk" as we have with "inmem". We're basically opting out of badger's
currency control and transactionality guarantees. This is because we
cannot piggy back on that to ensure the atomic update we want.
There might be other ways -- using subscribers, and blocking in some
other place -- but this one seems preferrable since it mirrors inmem.
Part of the problem is ErrTxnTooLarge, and committing and renewing
txns when it occurs: that, which is the prescribed solution to txns
growing too big, also means that reads can see half of the "logical"
transaction having been committed, while the rest is still getting
processed.
Another approach would have been using `WriteBatch`, but that won't
let us read from the batch, only apply Set and Delete operations.
We currently need to read (via an iterator) to figure out if we
need to delete keys to replace something in the store. There is
no DropPrefix operation on the badger txn, or the WriteBatch API.
storage/disk: remove commit-and-renew-txn code for txn-too-big errors
This would break transactional guarantees we care about: while there
can be only one write transaction at a time, read transactions may
happen while a write txn is underway -- with this commit-and-reset
logic, those would read partial data.
Now, the error will be returned to the caller. The maximum txn size
depends on the size of memtables, and could be tweaked manually.
In general, the caller should try to push multiple smaller increments
of the data.
storage/disk: implement noop MakeDir
The MakeDir operation as implemented in the backend-agnostic storage
code has become an issue with the disk store: to write /foo/bar/baz,
we'd have to read /foo (among other subdirs), and that can be _much_
work for the disk backend. With inmem, it's cheap, so this wasn't
problematic before.
Some of the storage/disk/txn.go logic had to be adjusted to properly
do the MakeDir steps implicitly.
The index argument addition to patch() in storage/disk/txn.go was
necessary to keep the error messages conforming to the previous
code path: previously, conflicts (arrays indexed as objects) would
be surfaced in the MakeDir step, now it's entangled with the patch
calculation.
storage/disk: check ctx.Err() in List/Get operations
This won't abort reading a single key, but it will abort iterations.
storage/disk: support patterns in partitions
There is a potential clash here: "*", the path wildcard, is
a valid path section. However, it only affects the case when
a user would want to have a partition at
/foo/*/bar
and would really mean "*", and not the wildcard.
Storing data at /foo/*/bar with a literal "*" won't be treated
differently than storing something at /fo/xyz/bar.
storage/disk: keep per-txn-type histograms of stats
This is done by reading off the metrics on commit, and shovelling
their numbers into the prometheus collector.
NOTE: if you were to share a metrics object among multiple transactions,
the results would be skewed, as it's not reset. However, our server
handlers don't do that.
storage/disk: opt out of badger's conflict detection
With only one write transaction in flight at any time, the situation
that badger guards against cannot happen:
A transaction has written to a key after the current, to-be-committed
transaction has last read that key from the store.
Since it can't happen, we can ignore the bookkeeping involved. This
improves the time it takes to overwrite existing keys.
Signed-off-by: Stephan Renatus <stephan.renatus@gmail.com>
This change adds an api_usage_warning when input attribute is missing in POST requests to /v1/data
Fixes: #4386
Signed-off-by: Alam <afaaqalam@gmail.com>
Adding the ability to partially evaluate when using the the SDK as a go library.
This allows for utilizing the existing OPA configuration (e.g. bundle, decisions,
etc) when partially evaluating.
Signed-off-by: Kurt Roekle <kroekle@gmail.com>
This change enables consumers of Compile API to specify packages
those should not be inlined in partial evaluation response.
Fixes: #4357
Signed-off-by: skosunda <skosunda@adobe.com>
... so applications can perform more informed error handling, e.g. refresh credentials on 403.
Fixes#4259.
Signed-off-by: Jakob Schmid <jakob.schmid@sap.com>
Earlier a snapshot bundle would describe the full state of OPA's
policy/data and any update would require first erasing the state from
the existing bundle and then activating the new bundle.
This commit introduces a new bundle type called "delta".
Delta bundles contain patches to data instead of snapshots.
They allow users to efficiently make updates to OPA's data
cache.
Signed-off-by: Ashutosh Narkar <anarkar4387@gmail.com>
1. I think an extra section on OT is warranted, even if it's brief.
2. The config now expects "type" to be set to "grpc" to enable the current
feature set. More options may follow in the future.
This is meant to future-proof the config. Future values might include
"http", where the address, TLS and sampling related settings would be
reused; and "global", where the setup would use whatever global trace
provider was configured with otel. The latter use case would be for
embedding OPA via the SDK.
3. Decision ID attributes are only added to spans if decision logging is enabled.
Fixes#4128.
Signed-off-by: Stephan Renatus <stephan.renatus@gmail.com>
This deals with the first two bullets of #4128:
1. tracing for remaining handlers
2. decisions IDs are added to the server spans
I'm not sure if that's the convention, but I've put the decision ID into the server
spans: the client spans we get from http.send usage in policies will not carry
them, but they do refer to their parents, and they'll have the `opa.decision_id`
attribute.
Also includes some general cleanup:
* server/writer: use switch for ErrorAuto()
* server: replace http statuses with their constants
Signed-off-by: Stephan Renatus <stephan.renatus@gmail.com>
Ashutosh Narkar