# Varnish Input Plugin

This plugin gathers stats from [Varnish HTTP Cache](https://varnish-cache.org/)

### Configuration:

```toml
[[inputs.varnish]]
  ## If running as a restricted user you can prepend sudo for additional access:
  #use_sudo = false

  ## The default location of the varnishstat binary can be overridden with:
  binary = "/usr/bin/varnishstat"

  ## By default, telegraf gather stats for 3 metric points.
  ## Setting stats will override the defaults shown below.
  ## Glob matching can be used, ie, stats = ["MAIN.*"]
  ## stats may also be set to ["*"], which will collect all stats
  stats = ["MAIN.cache_hit", "MAIN.cache_miss", "MAIN.uptime"]

  ## Optional name for the varnish instance (or working directory) to query
  ## Usually appened after -n in varnish cli
  # instance_name = instanceName

  ## Timeout for varnishstat command
  # timeout = "1s"
```

### Measurements & Fields:

This is the full list of stats provided by varnish. Stats will be grouped by their capitalized prefix (eg MAIN, 
MEMPOOL, etc). In the output, the prefix will be used as a tag, and removed from field names.

- varnish
    - MAIN.uptime                                    (uint64, count,  Child process uptime)
    - MAIN.sess_conn                                 (uint64, count,  Sessions accepted)
    - MAIN.sess_drop                                 (uint64, count,  Sessions dropped)
    - MAIN.sess_fail                                 (uint64, count,  Session accept failures)
    - MAIN.sess_pipe_overflow                        (uint64, count,  Session pipe overflow)
    - MAIN.client_req_400                            (uint64, count,  Client requests received,)
    - MAIN.client_req_411                            (uint64, count,  Client requests received,)
    - MAIN.client_req_413                            (uint64, count,  Client requests received,)
    - MAIN.client_req_417                            (uint64, count,  Client requests received,)
    - MAIN.client_req                                (uint64, count,  Good client requests)
    - MAIN.cache_hit                                 (uint64, count,  Cache hits)
    - MAIN.cache_hitpass                             (uint64, count,  Cache hits for)
    - MAIN.cache_miss                                (uint64, count,  Cache misses)
    - MAIN.backend_conn                              (uint64, count,  Backend conn. success)
    - MAIN.backend_unhealthy                         (uint64, count,  Backend conn. not)
    - MAIN.backend_busy                              (uint64, count,  Backend conn. too)
    - MAIN.backend_fail                              (uint64, count,  Backend conn. failures)
    - MAIN.backend_reuse                             (uint64, count,  Backend conn. reuses)
    - MAIN.backend_toolate                           (uint64, count,  Backend conn. was)
    - MAIN.backend_recycle                           (uint64, count,  Backend conn. recycles)
    - MAIN.backend_retry                             (uint64, count,  Backend conn. retry)
    - MAIN.fetch_head                                (uint64, count,  Fetch no body)
    - MAIN.fetch_length                              (uint64, count,  Fetch with Length)
    - MAIN.fetch_chunked                             (uint64, count,  Fetch chunked)
    - MAIN.fetch_eof                                 (uint64, count,  Fetch EOF)
    - MAIN.fetch_bad                                 (uint64, count,  Fetch bad T- E)
    - MAIN.fetch_close                               (uint64, count,  Fetch wanted close)
    - MAIN.fetch_oldhttp                             (uint64, count,  Fetch pre HTTP/1.1)
    - MAIN.fetch_zero                                (uint64, count,  Fetch zero len)
    - MAIN.fetch_1xx                                 (uint64, count,  Fetch no body)
    - MAIN.fetch_204                                 (uint64, count,  Fetch no body)
    - MAIN.fetch_304                                 (uint64, count,  Fetch no body)
    - MAIN.fetch_failed                              (uint64, count,  Fetch failed (all)
    - MAIN.fetch_no_thread                           (uint64, count,  Fetch failed (no)
    - MAIN.pools                                     (uint64, count,  Number of thread)
    - MAIN.threads                                   (uint64, count,  Total number of)
    - MAIN.threads_limited                           (uint64, count,  Threads hit max)
    - MAIN.threads_created                           (uint64, count,  Threads created)
    - MAIN.threads_destroyed                         (uint64, count,  Threads destroyed)
    - MAIN.threads_failed                            (uint64, count,  Thread creation failed)
    - MAIN.thread_queue_len                          (uint64, count,  Length of session)
    - MAIN.busy_sleep                                (uint64, count,  Number of requests)
    - MAIN.busy_wakeup                               (uint64, count,  Number of requests)
    - MAIN.sess_queued                               (uint64, count,  Sessions queued for)
    - MAIN.sess_dropped                              (uint64, count,  Sessions dropped for)
    - MAIN.n_object                                  (uint64, count,  object structs made)
    - MAIN.n_vampireobject                           (uint64, count,  unresurrected objects)
    - MAIN.n_objectcore                              (uint64, count,  objectcore structs made)
    - MAIN.n_objecthead                              (uint64, count,  objecthead structs made)
    - MAIN.n_waitinglist                             (uint64, count,  waitinglist structs made)
    - MAIN.n_backend                                 (uint64, count,  Number of backends)
    - MAIN.n_expired                                 (uint64, count,  Number of expired)
    - MAIN.n_lru_nuked                               (uint64, count,  Number of LRU)
    - MAIN.n_lru_moved                               (uint64, count,  Number of LRU)
    - MAIN.losthdr                                   (uint64, count,  HTTP header overflows)
    - MAIN.s_sess                                    (uint64, count,  Total sessions seen)
    - MAIN.s_req                                     (uint64, count,  Total requests seen)
    - MAIN.s_pipe                                    (uint64, count,  Total pipe sessions)
    - MAIN.s_pass                                    (uint64, count,  Total pass- ed requests)
    - MAIN.s_fetch                                   (uint64, count,  Total backend fetches)
    - MAIN.s_synth                                   (uint64, count,  Total synthethic responses)
    - MAIN.s_req_hdrbytes                            (uint64, count,  Request header bytes)
    - MAIN.s_req_bodybytes                           (uint64, count,  Request body bytes)
    - MAIN.s_resp_hdrbytes                           (uint64, count,  Response header bytes)
    - MAIN.s_resp_bodybytes                          (uint64, count,  Response body bytes)
    - MAIN.s_pipe_hdrbytes                           (uint64, count,  Pipe request header)
    - MAIN.s_pipe_in                                 (uint64, count,  Piped bytes from)
    - MAIN.s_pipe_out                                (uint64, count,  Piped bytes to)
    - MAIN.sess_closed                               (uint64, count,  Session Closed)
    - MAIN.sess_pipeline                             (uint64, count,  Session Pipeline)
    - MAIN.sess_readahead                            (uint64, count,  Session Read Ahead)
    - MAIN.sess_herd                                 (uint64, count,  Session herd)
    - MAIN.shm_records                               (uint64, count,  SHM records)
    - MAIN.shm_writes                                (uint64, count,  SHM writes)
    - MAIN.shm_flushes                               (uint64, count,  SHM flushes due)
    - MAIN.shm_cont                                  (uint64, count,  SHM MTX contention)
    - MAIN.shm_cycles                                (uint64, count,  SHM cycles through)
    - MAIN.sms_nreq                                  (uint64, count,  SMS allocator requests)
    - MAIN.sms_nobj                                  (uint64, count,  SMS outstanding allocations)
    - MAIN.sms_nbytes                                (uint64, count,  SMS outstanding bytes)
    - MAIN.sms_balloc                                (uint64, count,  SMS bytes allocated)
    - MAIN.sms_bfree                                 (uint64, count,  SMS bytes freed)
    - MAIN.backend_req                               (uint64, count,  Backend requests made)
    - MAIN.n_vcl                                     (uint64, count,  Number of loaded)
    - MAIN.n_vcl_avail                               (uint64, count,  Number of VCLs)
    - MAIN.n_vcl_discard                             (uint64, count,  Number of discarded)
    - MAIN.bans                                      (uint64, count,  Count of bans)
    - MAIN.bans_completed                            (uint64, count,  Number of bans)
    - MAIN.bans_obj                                  (uint64, count,  Number of bans)
    - MAIN.bans_req                                  (uint64, count,  Number of bans)
    - MAIN.bans_added                                (uint64, count,  Bans added)
    - MAIN.bans_deleted                              (uint64, count,  Bans deleted)
    - MAIN.bans_tested                               (uint64, count,  Bans tested against)
    - MAIN.bans_obj_killed                           (uint64, count,  Objects killed by)
    - MAIN.bans_lurker_tested                        (uint64, count,  Bans tested against)
    - MAIN.bans_tests_tested                         (uint64, count,  Ban tests tested)
    - MAIN.bans_lurker_tests_tested                  (uint64, count,  Ban tests tested)
    - MAIN.bans_lurker_obj_killed                    (uint64, count,  Objects killed by)
    - MAIN.bans_dups                                 (uint64, count,  Bans superseded by)
    - MAIN.bans_lurker_contention                    (uint64, count,  Lurker gave way)
    - MAIN.bans_persisted_bytes                      (uint64, count,  Bytes used by)
    - MAIN.bans_persisted_fragmentation              (uint64, count,  Extra bytes in)
    - MAIN.n_purges                                  (uint64, count,  Number of purge)
    - MAIN.n_obj_purged                              (uint64, count,  Number of purged)
    - MAIN.exp_mailed                                (uint64, count,  Number of objects)
    - MAIN.exp_received                              (uint64, count,  Number of objects)
    - MAIN.hcb_nolock                                (uint64, count,  HCB Lookups without)
    - MAIN.hcb_lock                                  (uint64, count,  HCB Lookups with)
    - MAIN.hcb_insert                                (uint64, count,  HCB Inserts)
    - MAIN.esi_errors                                (uint64, count,  ESI parse errors)
    - MAIN.esi_warnings                              (uint64, count,  ESI parse warnings)
    - MAIN.vmods                                     (uint64, count,  Loaded VMODs)
    - MAIN.n_gzip                                    (uint64, count,  Gzip operations)
    - MAIN.n_gunzip                                  (uint64, count,  Gunzip operations)
    - MAIN.vsm_free                                  (uint64, count,  Free VSM space)
    - MAIN.vsm_used                                  (uint64, count,  Used VSM space)
    - MAIN.vsm_cooling                               (uint64, count,  Cooling VSM space)
    - MAIN.vsm_overflow                              (uint64, count,  Overflow VSM space)
    - MAIN.vsm_overflowed                            (uint64, count,  Overflowed VSM space)
    - MGT.uptime                                     (uint64, count,  Management process uptime)
    - MGT.child_start                                (uint64, count,  Child process started)
    - MGT.child_exit                                 (uint64, count,  Child process normal)
    - MGT.child_stop                                 (uint64, count,  Child process unexpected)
    - MGT.child_died                                 (uint64, count,  Child process died)
    - MGT.child_dump                                 (uint64, count,  Child process core)
    - MGT.child_panic                                (uint64, count,  Child process panic)
    - MEMPOOL.vbc.live                               (uint64, count,  In use)
    - MEMPOOL.vbc.pool                               (uint64, count,  In Pool)
    - MEMPOOL.vbc.sz_wanted                          (uint64, count,  Size requested)
    - MEMPOOL.vbc.sz_needed                          (uint64, count,  Size allocated)
    - MEMPOOL.vbc.allocs                             (uint64, count,  Allocations )
    - MEMPOOL.vbc.frees                              (uint64, count,  Frees )
    - MEMPOOL.vbc.recycle                            (uint64, count,  Recycled from pool)
    - MEMPOOL.vbc.timeout                            (uint64, count,  Timed out from)
    - MEMPOOL.vbc.toosmall                           (uint64, count,  Too small to)
    - MEMPOOL.vbc.surplus                            (uint64, count,  Too many for)
    - MEMPOOL.vbc.randry                             (uint64, count,  Pool ran dry)
    - MEMPOOL.busyobj.live                           (uint64, count,  In use)
    - MEMPOOL.busyobj.pool                           (uint64, count,  In Pool)
    - MEMPOOL.busyobj.sz_wanted                      (uint64, count,  Size requested)
    - MEMPOOL.busyobj.sz_needed                      (uint64, count,  Size allocated)
    - MEMPOOL.busyobj.allocs                         (uint64, count,  Allocations )
    - MEMPOOL.busyobj.frees                          (uint64, count,  Frees )
    - MEMPOOL.busyobj.recycle                        (uint64, count,  Recycled from pool)
    - MEMPOOL.busyobj.timeout                        (uint64, count,  Timed out from)
    - MEMPOOL.busyobj.toosmall                       (uint64, count,  Too small to)
    - MEMPOOL.busyobj.surplus                        (uint64, count,  Too many for)
    - MEMPOOL.busyobj.randry                         (uint64, count,  Pool ran dry)
    - MEMPOOL.req0.live                              (uint64, count,  In use)
    - MEMPOOL.req0.pool                              (uint64, count,  In Pool)
    - MEMPOOL.req0.sz_wanted                         (uint64, count,  Size requested)
    - MEMPOOL.req0.sz_needed                         (uint64, count,  Size allocated)
    - MEMPOOL.req0.allocs                            (uint64, count,  Allocations )
    - MEMPOOL.req0.frees                             (uint64, count,  Frees )
    - MEMPOOL.req0.recycle                           (uint64, count,  Recycled from pool)
    - MEMPOOL.req0.timeout                           (uint64, count,  Timed out from)
    - MEMPOOL.req0.toosmall                          (uint64, count,  Too small to)
    - MEMPOOL.req0.surplus                           (uint64, count,  Too many for)
    - MEMPOOL.req0.randry                            (uint64, count,  Pool ran dry)
    - MEMPOOL.sess0.live                             (uint64, count,  In use)
    - MEMPOOL.sess0.pool                             (uint64, count,  In Pool)
    - MEMPOOL.sess0.sz_wanted                        (uint64, count,  Size requested)
    - MEMPOOL.sess0.sz_needed                        (uint64, count,  Size allocated)
    - MEMPOOL.sess0.allocs                           (uint64, count,  Allocations )
    - MEMPOOL.sess0.frees                            (uint64, count,  Frees )
    - MEMPOOL.sess0.recycle                          (uint64, count,  Recycled from pool)
    - MEMPOOL.sess0.timeout                          (uint64, count,  Timed out from)
    - MEMPOOL.sess0.toosmall                         (uint64, count,  Too small to)
    - MEMPOOL.sess0.surplus                          (uint64, count,  Too many for)
    - MEMPOOL.sess0.randry                           (uint64, count,  Pool ran dry)
    - MEMPOOL.req1.live                              (uint64, count,  In use)
    - MEMPOOL.req1.pool                              (uint64, count,  In Pool)
    - MEMPOOL.req1.sz_wanted                         (uint64, count,  Size requested)
    - MEMPOOL.req1.sz_needed                         (uint64, count,  Size allocated)
    - MEMPOOL.req1.allocs                            (uint64, count,  Allocations )
    - MEMPOOL.req1.frees                             (uint64, count,  Frees )
    - MEMPOOL.req1.recycle                           (uint64, count,  Recycled from pool)
    - MEMPOOL.req1.timeout                           (uint64, count,  Timed out from)
    - MEMPOOL.req1.toosmall                          (uint64, count,  Too small to)
    - MEMPOOL.req1.surplus                           (uint64, count,  Too many for)
    - MEMPOOL.req1.randry                            (uint64, count,  Pool ran dry)
    - MEMPOOL.sess1.live                             (uint64, count,  In use)
    - MEMPOOL.sess1.pool                             (uint64, count,  In Pool)
    - MEMPOOL.sess1.sz_wanted                        (uint64, count,  Size requested)
    - MEMPOOL.sess1.sz_needed                        (uint64, count,  Size allocated)
    - MEMPOOL.sess1.allocs                           (uint64, count,  Allocations )
    - MEMPOOL.sess1.frees                            (uint64, count,  Frees )
    - MEMPOOL.sess1.recycle                          (uint64, count,  Recycled from pool)
    - MEMPOOL.sess1.timeout                          (uint64, count,  Timed out from)
    - MEMPOOL.sess1.toosmall                         (uint64, count,  Too small to)
    - MEMPOOL.sess1.surplus                          (uint64, count,  Too many for)
    - MEMPOOL.sess1.randry                           (uint64, count,  Pool ran dry)
    - SMA.s0.c_req                                   (uint64, count,  Allocator requests)
    - SMA.s0.c_fail                                  (uint64, count,  Allocator failures)
    - SMA.s0.c_bytes                                 (uint64, count,  Bytes allocated)
    - SMA.s0.c_freed                                 (uint64, count,  Bytes freed)
    - SMA.s0.g_alloc                                 (uint64, count,  Allocations outstanding)
    - SMA.s0.g_bytes                                 (uint64, count,  Bytes outstanding)
    - SMA.s0.g_space                                 (uint64, count,  Bytes available)
    - SMA.Transient.c_req                            (uint64, count,  Allocator requests)
    - SMA.Transient.c_fail                           (uint64, count,  Allocator failures)
    - SMA.Transient.c_bytes                          (uint64, count,  Bytes allocated)
    - SMA.Transient.c_freed                          (uint64, count,  Bytes freed)
    - SMA.Transient.g_alloc                          (uint64, count,  Allocations outstanding)
    - SMA.Transient.g_bytes                          (uint64, count,  Bytes outstanding)
    - SMA.Transient.g_space                          (uint64, count,  Bytes available)
    - VBE.default(127.0.0.1,,8080).vcls              (uint64, count,  VCL references)
    - VBE.default(127.0.0.1,,8080).happy             (uint64, count,  Happy health probes)
    - VBE.default(127.0.0.1,,8080).bereq_hdrbytes    (uint64, count,  Request header bytes)
    - VBE.default(127.0.0.1,,8080).bereq_bodybytes   (uint64, count,  Request body bytes)
    - VBE.default(127.0.0.1,,8080).beresp_hdrbytes   (uint64, count,  Response header bytes)
    - VBE.default(127.0.0.1,,8080).beresp_bodybytes  (uint64, count,  Response body bytes)
    - VBE.default(127.0.0.1,,8080).pipe_hdrbytes     (uint64, count,  Pipe request header)
    - VBE.default(127.0.0.1,,8080).pipe_out          (uint64, count,  Piped bytes to)
    - VBE.default(127.0.0.1,,8080).pipe_in           (uint64, count,  Piped bytes from)
    - LCK.sms.creat                                  (uint64, count,  Created locks)
    - LCK.sms.destroy                                (uint64, count,  Destroyed locks)
    - LCK.sms.locks                                  (uint64, count,  Lock Operations)
    - LCK.smp.creat                                  (uint64, count,  Created locks)
    - LCK.smp.destroy                                (uint64, count,  Destroyed locks)
    - LCK.smp.locks                                  (uint64, count,  Lock Operations)
    - LCK.sma.creat                                  (uint64, count,  Created locks)
    - LCK.sma.destroy                                (uint64, count,  Destroyed locks)
    - LCK.sma.locks                                  (uint64, count,  Lock Operations)
    - LCK.smf.creat                                  (uint64, count,  Created locks)
    - LCK.smf.destroy                                (uint64, count,  Destroyed locks)
    - LCK.smf.locks                                  (uint64, count,  Lock Operations)
    - LCK.hsl.creat                                  (uint64, count,  Created locks)
    - LCK.hsl.destroy                                (uint64, count,  Destroyed locks)
    - LCK.hsl.locks                                  (uint64, count,  Lock Operations)
    - LCK.hcb.creat                                  (uint64, count,  Created locks)
    - LCK.hcb.destroy                                (uint64, count,  Destroyed locks)
    - LCK.hcb.locks                                  (uint64, count,  Lock Operations)
    - LCK.hcl.creat                                  (uint64, count,  Created locks)
    - LCK.hcl.destroy                                (uint64, count,  Destroyed locks)
    - LCK.hcl.locks                                  (uint64, count,  Lock Operations)
    - LCK.vcl.creat                                  (uint64, count,  Created locks)
    - LCK.vcl.destroy                                (uint64, count,  Destroyed locks)
    - LCK.vcl.locks                                  (uint64, count,  Lock Operations)
    - LCK.sessmem.creat                              (uint64, count,  Created locks)
    - LCK.sessmem.destroy                            (uint64, count,  Destroyed locks)
    - LCK.sessmem.locks                              (uint64, count,  Lock Operations)
    - LCK.sess.creat                                 (uint64, count,  Created locks)
    - LCK.sess.destroy                               (uint64, count,  Destroyed locks)
    - LCK.sess.locks                                 (uint64, count,  Lock Operations)
    - LCK.wstat.creat                                (uint64, count,  Created locks)
    - LCK.wstat.destroy                              (uint64, count,  Destroyed locks)
    - LCK.wstat.locks                                (uint64, count,  Lock Operations)
    - LCK.herder.creat                               (uint64, count,  Created locks)
    - LCK.herder.destroy                             (uint64, count,  Destroyed locks)
    - LCK.herder.locks                               (uint64, count,  Lock Operations)
    - LCK.wq.creat                                   (uint64, count,  Created locks)
    - LCK.wq.destroy                                 (uint64, count,  Destroyed locks)
    - LCK.wq.locks                                   (uint64, count,  Lock Operations)
    - LCK.objhdr.creat                               (uint64, count,  Created locks)
    - LCK.objhdr.destroy                             (uint64, count,  Destroyed locks)
    - LCK.objhdr.locks                               (uint64, count,  Lock Operations)
    - LCK.exp.creat                                  (uint64, count,  Created locks)
    - LCK.exp.destroy                                (uint64, count,  Destroyed locks)
    - LCK.exp.locks                                  (uint64, count,  Lock Operations)
    - LCK.lru.creat                                  (uint64, count,  Created locks)
    - LCK.lru.destroy                                (uint64, count,  Destroyed locks)
    - LCK.lru.locks                                  (uint64, count,  Lock Operations)
    - LCK.cli.creat                                  (uint64, count,  Created locks)
    - LCK.cli.destroy                                (uint64, count,  Destroyed locks)
    - LCK.cli.locks                                  (uint64, count,  Lock Operations)
    - LCK.ban.creat                                  (uint64, count,  Created locks)
    - LCK.ban.destroy                                (uint64, count,  Destroyed locks)
    - LCK.ban.locks                                  (uint64, count,  Lock Operations)
    - LCK.vbp.creat                                  (uint64, count,  Created locks)
    - LCK.vbp.destroy                                (uint64, count,  Destroyed locks)
    - LCK.vbp.locks                                  (uint64, count,  Lock Operations)
    - LCK.backend.creat                              (uint64, count,  Created locks)
    - LCK.backend.destroy                            (uint64, count,  Destroyed locks)
    - LCK.backend.locks                              (uint64, count,  Lock Operations)
    - LCK.vcapace.creat                              (uint64, count,  Created locks)
    - LCK.vcapace.destroy                            (uint64, count,  Destroyed locks)
    - LCK.vcapace.locks                              (uint64, count,  Lock Operations)
    - LCK.nbusyobj.creat                             (uint64, count,  Created locks)
    - LCK.nbusyobj.destroy                           (uint64, count,  Destroyed locks)
    - LCK.nbusyobj.locks                             (uint64, count,  Lock Operations)
    - LCK.busyobj.creat                              (uint64, count,  Created locks)
    - LCK.busyobj.destroy                            (uint64, count,  Destroyed locks)
    - LCK.busyobj.locks                              (uint64, count,  Lock Operations)
    - LCK.mempool.creat                              (uint64, count,  Created locks)
    - LCK.mempool.destroy                            (uint64, count,  Destroyed locks)
    - LCK.mempool.locks                              (uint64, count,  Lock Operations)
    - LCK.vxid.creat                                 (uint64, count,  Created locks)
    - LCK.vxid.destroy                               (uint64, count,  Destroyed locks)
    - LCK.vxid.locks                                 (uint64, count,  Lock Operations)
    - LCK.pipestat.creat                             (uint64, count,  Created locks)
    - LCK.pipestat.destroy                           (uint64, count,  Destroyed locks)
    - LCK.pipestat.locks                             (uint64, count,  Lock Operations)


### Tags:

As indicated above, the  prefix of a varnish stat will be used as it's 'section' tag. So section tag may have one of 
the following values:
- section:
  - MAIN
  - MGT
  - MEMPOOL
  - SMA
  - VBE
  - LCK
  
  

### Permissions:

It's important to note that this plugin references varnishstat, which may require additional permissions to execute successfully.
Depending on the user/group permissions of the telegraf user executing this plugin, you may need to alter the group membership, set facls, or use sudo.

**Group membership (Recommended)**:
```bash
$ groups telegraf
telegraf : telegraf

$ usermod -a -G varnish telegraf

$ groups telegraf
telegraf : telegraf varnish
```

**Extended filesystem ACL's**:
```bash
$ getfacl /var/lib/varnish/<hostname>/_.vsm
# file: var/lib/varnish/<hostname>/_.vsm
# owner: root
# group: root
user::rw-
group::r--
other::---

$ setfacl -m u:telegraf:r /var/lib/varnish/<hostname>/_.vsm

$ getfacl /var/lib/varnish/<hostname>/_.vsm
# file: var/lib/varnish/<hostname>/_.vsm
# owner: root
# group: root
user::rw-
user:telegraf:r--
group::r--
mask::r--
other::---
```

**Sudo privileges**:
If you use this method, you will need the following in your telegraf config:
```toml
[[inputs.varnish]]
  use_sudo = true
```

You will also need to update your sudoers file:
```bash
$ visudo
# Add the following line:
Cmnd_Alias VARNISHSTAT = /usr/bin/varnishstat
telegraf  ALL=(ALL) NOPASSWD: VARNISHSTAT
Defaults!VARNISHSTAT !logfile, !syslog, !pam_session
```

Please use the solution you see as most appropriate.

### Example Output:

```
 telegraf --config etc/telegraf.conf --input-filter varnish --test
* Plugin: varnish, Collection 1
> varnish,host=rpercy-VirtualBox,section=MAIN cache_hit=0i,cache_miss=0i,uptime=8416i 1462765437090957980
```
